From ravi.reddy@REDACTED  Mon Apr  3 12:10:52 2000
From: ravi.reddy@REDACTED (Ravi kumar reddy K)
Date: Mon, 3 Apr 2000 15:40:52 +0530
Subject: Queries on SNMP over OTP...
Message-ID: <006401bf9d54$e4b760a0$4a8ea8c0@reddy.wipsys.stph.net>

We are facing problem in startiung the master SNMP agent on an erlang node.
 
The following are the messages that are outcome of the command 
application:start(snmp) at the erlang shell (ver 47.4.1) 

application: snmp
exited: "invalid return value from snmp_app:start(normal,[]) -> {'EXIT',undefined_config,{snmp,snmp_db_dir}}}"
type: temporary
{error,"invalid return value from snmp_app:start(normal,[]) -> {'EXIT',undefined_config,{snmp,snmp_db_dir}}}"}

Regards,

K. Ravi Kumar Reddy

G. Prasanna Kumar
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From Chandru.Mullaparthi@REDACTED  Mon Apr  3 12:23:03 2000
From: Chandru.Mullaparthi@REDACTED (Chandrashekhar M)
Date: Mon, 03 Apr 2000 11:23:03 +0100
Subject: Queries on SNMP over OTP...
References: <006401bf9d54$e4b760a0$4a8ea8c0@reddy.wipsys.stph.net>
Message-ID: <38E87107.7B5951C6@eei.ericsson.se>

Ravi kumar reddy K wrote:
> We are facing problem in startiung the master SNMP agent on an erlang
> node.
>  
> The following are the messages that are outcome of the command 
> application:start(snmp) at the erlang shell (ver 47.4.1) 
>  
> 
> application: snmp
> exited: "invalid return value from snmp_app:start(normal,[]) ->
> {'EXIT',undefined_config,{snmp,snmp_db_dir}}}"
> type: temporary
> {error,"invalid return value from snmp_app:start(normal,[]) ->
> {'EXIT',undefined_config,{snmp,snmp_db_dir}}}"}

You have to specify values for the snmp_db_dir and snmp_config_dir

>From the command line of the erl shell you can do it as:

erl -snmp snmp_db_dir '"Your db dir"' \
-snmp snmp_config_dir '"Your config dir"' <other erl options>

Those directories have to be created prior to starting the 
master agent.

Or you can specify values for those variables in a config file.
Check the documentation for erl.

hth
Chandru

-- 
Random Wodehouse Quote

I could see that she was looking for something to break as a relief to
her surging emotions ... and courteously drew her attention to a
terra-cotta figure of the Infant Samuel at Prayer. She thanked me
briefly and hurled it against the opposite wall.


From prasanna.galla@REDACTED  Mon Apr  3 14:17:47 2000
From: prasanna.galla@REDACTED (Prasanna Kumar Galla)
Date: Mon, 03 Apr 2000 17:47:47 +0530
Subject: starting snmp...?
Message-ID: <38E88BEB.2E0A2DA5@wipsys.stph.net>

I have the erlang package at..
c: \ programfiles \ erl47.4.1
on windows95.

now my aim is to start snmp agent in the shell
and load the existing MIB "Ex1-MIB.mib" provided in examples

just help me in this reg.

also clarify..
whether i should create 2 directories -one for snmp_db_dir ,the other
for snmp_config_dir....
or else i should set any of the existing directories...

Thanks in advance.

Regards,
prasanna.



From Chandru.Mullaparthi@REDACTED  Mon Apr  3 15:28:25 2000
From: Chandru.Mullaparthi@REDACTED (Chandrashekhar M)
Date: Mon, 03 Apr 2000 14:28:25 +0100
Subject: starting snmp...?
References: <38E88BEB.2E0A2DA5@wipsys.stph.net>
Message-ID: <38E89C79.7758BBDB@eei.ericsson.se>

Prasanna Kumar Galla wrote:
> 
> I have the erlang package at..
> c: \ programfiles \ erl47.4.1
> on windows95.
> 
> now my aim is to start snmp agent in the shell
> and load the existing MIB "Ex1-MIB.mib" provided in examples
> 
> just help me in this reg.

% erl -snmp snmp_db_dir '"./snmp"' -snmp snmp_config_dir '"./config"'

 ( assuming ./snmp is your snmp_db_dr and ./config is your 
   snmp_config_dir )
Erlang (BEAM) emulator version 4.8.2

Eshell V4.8.2  (abort with ^G)
1> application:start(snmp).

> also clarify..
> whether i should create 2 directories -one for snmp_db_dir ,the other
> for snmp_config_dir....
> or else i should set any of the existing directories...
You can specify an existing dir - and you can specify the same dir for
both. 

hth
Chandru


From luke@REDACTED  Wed Apr  5 08:27:24 2000
From: luke@REDACTED (Luke Gorrie)
Date: 05 Apr 2000 08:27:24 +0200
Subject: The Return of Wikie
Message-ID: <874s9hkqpf.fsf@cockatoo.bluetail.com>

At long last, Wikie is back to stay! The new URL is

  http://203.46.39.99:2000/

A proper hostname will be assigned soon. The vegetable.org kingdom
isn't what it once was, so bear with me :-).

Cheers,
Luke



From luke@REDACTED  Wed Apr  5 07:34:09 2000
From: luke@REDACTED (Luke Gorrie)
Date: 05 Apr 2000 07:34:09 +0200
Subject: The Return of Wikie
Message-ID: <877ledkt66.fsf@cockatoo.bluetail.com>

At long last, Wikie is back to stay! The new URL is

  http://203.46.39.99:2000/

A proper hostname will be assigned soon. The vegetable.org kingdom
isn't what it once was, so bear with me :-).

Cheers,
Luke



From sanjiva@REDACTED  Fri Apr  7 00:13:19 2000
From: sanjiva@REDACTED (Sanjiva Prasad)
Date: Fri, 7 Apr 2000 03:43:19 +0530
Subject: No subject
Message-ID: <200004062213.DAA00773@cse.iitd.ernet.in>


Subject: Second Call for Papers
FCC: ~/Mail/sent
--text follows this line--


***********************************************************************
*                                                                     *
*                            FST TCS 2000                             *
*                                                                     *
* Foundations of Software Technology and Theoretical Computer Science *
*                        December 13--15, 2000                        *
*                          New Delhi, India                           *
*                                                                     *
***********************************************************************
*                          Call for Papers                            *
***********************************************************************


IARCS, the Indian Association for Research in Computing Science,
announces the 20th Annual FST TCS Conference in New Delhi.  Two
satellite workshops are planned: on Computational Geometry and on
Advances in Programming Languages.

Authors are invited to submit papers presenting original and
unpublished research on **any** theoretical aspects of Computer
Science. Papers in applied areas with a strong foundational emphasis
are also welcome.  The proceedings of the last six years' conferences
(Springer-Verlag Lecture Notes in Computer Science volumes 880, 1026,
1180, 1346, 1530, 1738) give an idea of the kind of papers typically
presented at FST TCS.  Typical areas include (but are not restricted to):

         Automata, Languages and Computability 
         Randomized and Approximation Algorithms 
         Computational Geometry
         Computational Biology
         Combinatorial Optimization
         Graph and Network Algorithms 
         Complexity Theory 
         Parallel and Distributed Computing 
         New Models of Computation
         Concurrent, Real-time and Hybrid Systems 
         Logics of Programs and Modal Logics
         Database Theory  and Information Retrieval
         Automated Reasoning, Rewrite Systems, and Applications 
         Logic, Proof Theory, Model Theory and Applications
         Semantics of Programming Languages
         Static Analysis and  Type Systems
         Theory of Functional and Constraint-based Programming 
         Software Specification and Verification 
         Cryptography and Security Protocols


For an accepted paper to be included in the proceedings, one of 
the authors must commit to presenting the paper at the conference.

Important Dates
---------------
  Deadline for Submission                             31 May, 2000
  Notification to Authors                             15 August, 2000
  Final Version of Accepted Papers due                15 September, 2000
  Deadline for Early Registration	       		15 November, 2000 


Submission Guidelines
- ---------------------
Authors may submit drafts of full papers or extended abstracts.
Submissions are limited to 12 A4-size pages, with 1.5 inch top
margin and other margins 1 inch wide with 11 point or larger font.  
Authors who feel that more details are necessary may include a 
clearly marked appendix which will be read at the discretion of 
the Programme Committee.  Each paper should contain a short abstract.  
If available, e-mail addresses and fax numbers of the authors should 
be included.

Electronic Submissions
- ----------------------
Electronic submission is strongly encouraged.  Self-contained
uuencoded gzipped Postscript versions of the paper may be sent by
e-mail to 
		    fsttcs20@REDACTED

In addition, the following information in ASCII format should be 
sent to this address in a **separate** e-mail: Title; authors; 
communicating author's name, address, and e-mail address and 
fax number if available; abstract of paper.

Hard-Copy Submissions
- ---------------------
If electronic submission is not possible, authors may submit five 
(5) hard-copies of the paper by post to the following address:

		    FST TCS 2000
		    Department of Computer Science  and Engineering 
		    I.I.T., Delhi 
		    Hauz Khas
		    New Delhi 110 016
		    INDIA

Invited Speakers
----------------
Invited Speakers who have confirmed participation include:
 Peter Buneman (U Penn)
 Bernard Chazelle (Princeton)
 E. Allen Emerson (U Texas, Austin)
 Jose Meseguer (SRI)
 Philip Wadler (Bell Labs)


Programme Committee
-------------------

Pankaj Agarwal		(Duke)
Manindra Agrawal	      (IIT, Kanpur)		
Tetsuo Asano		(JAIST)
Vijay Chandru		(IISc, Bangalore)
Rance Cleaveland	      (Stony Brook)		
Anuj Dawar		      (Cambridge)			
Sampath Kannan		(AT&T Research)
Sanjiv Kapoor		(IIT, Delhi)		(Co-chair)
Kamal Lodaya		(IMSc, Chennai)		
Madhavan Mukund		(CMI, Chennai)		
Gopalan Nadathur	      (Loyola)			
Seffi Naor		      (Bell Labs and Technion)
Tobias Nipkow		(TU Munich)			
Luke Ong		      (Oxford)			
C. Pandu Rangan		(IIT, Chennai)
Paritosh Pandya		(TIFR)		
Benjamin Pierce		(U Penn)			
Sanjiva Prasad		(IIT, Delhi)		(Co-chair)		
Sridhar Rajagopalan     (IBM, Almaden)
Abhiram Ranade	      (IIT, Mumbai)
Dave Sands		      (Chalmers)	
A Prasad Sistla		(U Illinois, Chicago)	
Michiel Smid		(Magdeburg)
Mandayam K. Srivas	(SRI) 


Organized by
------------
Indian Institute of Technology, Delhi
Hauz Khas, New Delhi 100 016. 



Organizing Committee
-------------------
Sandeep Sen			(chair)
Naveen Garg			(treasurer)
S N Maheshwari

Conference Site
---------------
The Conference will take place at the India International Centre,
40 Lodhi Estate, Max Mueller Marg, New Delhi 110 003.

Correspondence Address
----------------------
All correspondence regarding submissions may be addressed to 

    FST TCS 2000
    Department of Computer Science  and Engineering 
    I.I.T., Delhi
    Hauz Khas, 
    New Delhi 110 016, INDIA

    Email:	  fsttcs20@REDACTED
    Fax:	  +91 11 686 8765
    Phone:	  +91 11 659 1294 / 659 1286
    URL:	  http://www.cse.iitd.ernet.in/~fsttcs20




-- 


				    Sanjiva Prasad
				 Associate Professor

Department of Computer Science and Engineering		sanjiva@REDACTED
Indian Institute of Technology, Delhi			(Off) +91 11 659 1294
Hauz Khas, New Delhi 110016					(Res) +91 11 659 1684
INDIA									(Fax) +91 11 686 8765

		    http://www.cse.iitd.ernet.in/~sanjiva



From jocke@REDACTED  Thu Apr  6 12:27:56 2000
From: jocke@REDACTED (Joakim G.)
Date: Thu, 06 Apr 2000 12:27:56 +0200
Subject: Jobs: Bluetail is hiring
Message-ID: <38EC66AC.28EA514A@bluetail.com>

Do you want to work with the original Erlang team?

Take a look at http://www.bluetail.com/company/jobs.shtml

/Jocke
--
http://www.bluetail.com


From Juergen.Bosch@REDACTED  Thu Apr  6 14:13:59 2000
From: Juergen.Bosch@REDACTED (=?iso-8859-1?Q?=22Bosch=2C_J=FCrgen=22?=)
Date: Thu, 6 Apr 2000 14:13:59 +0200 
Subject: WG: ORBER 2.x INFO
Message-ID: <896F3543BB0ED31190050000F878530F276A03@si11.technidata.de>

> Here you get my Questions in a other format:
> 
> ORB VERSION: _______________________
> How much cost the ORB ? _________________
> 
> Where can i get a free version for testing ? ________________________
> 
> ORB CORE MATRIX
> 
> 
> 	Language bindings
> Protocols		Core						
> IDL	C++	C	St	Ada	Java	COM	COBOL	IIOP	DCE
> DII	DSI	IR	IMR	BOA	POA
> 	
> 
> 
> C++ language binding 
> C language binding 
> St: Smalltalk language binding 
> Ada: language binding 
> Java: language binding (not yet standardized) 
> COM: integration with COM (not yet standardized) 
> COBOL language binding 
> IIOP: Internet Interoperability Protocol (mandatory) 
> DCE: DCE ESIOP (optional) 
> DII: dynamic invokation interface (mandatory) 
> DSI: dynamic skeleton interface (mandatory) 
> IR: interface repository (optional) 
> IMR: implementation repository
> BOA: Basic Object Adapter
> POA: Portable Object Adapter
> 
> CORBA Services
> 
> 
> NM	EV	LF	PO	TR	CC	RS	EX	QR	LI
> PR	TM	SE      OT       OC
> 	
> 
> 
> 
> NM: Naming Service
> EV: Event Service 
> LF: Life Cycle Service
> PO: Persistent Object Service
> TR: Transaction Service
> CC: Concurrency Control Service
> RS: Relationship Service
> EX: Externalization Service
> QR: Query Service
> LI: Licensing Service
> PR: Property Service
> TM: Time Service
> SE: Security Service
> OT: Object Trader Service
> OC: Object Collection Service
> 
> ADDITIONAL INFORMATIONS:
> 
> CORBA Vendor Platform Matrix
> 
> 
> src	Sol	HPUX	AIX	DEC	Linux	SGI	NT	W95/98	OS/2
> Mac	VMS	MVS
> 	
> 
> 
> thanks
> juergen bosch
> 
> Other platforms supported:
> 
> 
> -----Urspr?ngliche Nachricht-----
> Von:	Niclas Eklund [SMTP:nick@REDACTED]
> Gesendet am:	Donnerstag, 6. April 2000 13:57
> An:	juergen.bosch@REDACTED
> Betreff:	ORBER 2.x INFO
> 
> 
> Hello!
> 
> To be able to answer any of your questions I must ask you to supply your
> form in another format than .doc (don't use windows).
> 
> You can find some information at:
> 
> http://www.erlang.org/
> 
> 
> If you have any other Erlang/Orber related questions, please send them to:
> 
> erlang-questions@REDACTED
> 
> Best Regards
> 
> /Nick
> 
> 
> > Can you send me Informations about your ORB. I am working for Technidata
> > and i make a evaluation of ORBs. I want to make a publication of
> > commercials and free orbs, it is a part of my thesis.
> > Its very important for me and you have only to fill out the table in the
> > word document with yes , no or available in xxxx .
> >
> > <<ORB_info.doc>> 
> > 
> > Please fill out the word document and send it back to me.
> > EMAIL: juergen.bosch@REDACTED
> >
> > thanks
> > juergen bosch
> 
> 
> 
> 


From nick@REDACTED  Thu Apr  6 14:54:27 2000
From: nick@REDACTED (Niclas Eklund)
Date: Thu, 6 Apr 2000 14:54:27 +0200 (MET DST)
Subject: AW: ORBER 2.x INFO
In-Reply-To: <896F3543BB0ED31190050000F878530F276A02@si11.technidata.de>
Message-ID: <Pine.GSO.3.96.1000406142724.29351L-100000@shagrat>


> ORB VERSION: Released Orber-3.0.2, which supports
               most of the OMG CORBA-2.3 standard
> How much cost the ORB ? free (open source)
> 
> Where can i get a free version for testing ? http://www.erlang.org/
> 
> ORB CORE MATRIX
> 
> 
> 	Language bindings
> Protocols		Core						
> IDL	Erlang IIOP/GIOP (1.0 & 1.1)
> IR	BOA
> 	
> C++ language binding 
> C language binding 
> St: Smalltalk language binding 
> Ada: language binding 
> Java: language binding (not yet standardized) 
> COM: integration with COM (not yet standardized) 
> COBOL language binding 
> IIOP: Internet Interoperability Protocol (mandatory) 
> DCE: DCE ESIOP (optional) 
> DII: dynamic invokation interface (mandatory) 
> DSI: dynamic skeleton interface (mandatory) 
> IR: interface repository (optional) 
> IMR: implementation repository
> BOA: Basic Object Adapter
> POA: Portable Object Adapter
> 
> CORBA Services
> 
> 
> NM	EV (incl Notification soon)	TR
> TM (soon)	SE (ssl)
> 
> NM: Naming Service
> EV: Event Service 
> LF: Life Cycle Service
> PO: Persistent Object Service
> TR: Transaction Service
> CC: Concurrency Control Service
> RS: Relationship Service
> EX: Externalization Service
> QR: Query Service
> LI: Licensing Service
> PR: Property Service
> TM: Time Service
> SE: Security Service
> OT: Object Trader Service
> OC: Object Collection Service
> 
> ADDITIONAL INFORMATIONS:
> 
> CORBA Vendor Platform Matrix
> 
> 
> src	Sol	Linux	NT	W95/98   FreeBSD

Have a nice day

Nick






From scott@REDACTED  Fri Apr  7 19:15:44 2000
From: scott@REDACTED (Scott Lystig Fritchie)
Date: Fri, 07 Apr 2000 12:15:44 -0500
Subject: Socket owner changing code in inet_tcp.erl
Message-ID: <200004071715.MAA12226@snookles.snookles.com>

I've got a quick question about kernel-2.5's version of inet_tcp.erl:

	owner(Tcp, Owner, LIX, St, NewOwner) ->
	    receive
	        {commit_owner, NewOwner} ->
	            unlink(Owner),
	            link(NewOwner),
	            Owner ! {owner, NewOwner},
	            listen_loop(Tcp, NewOwner, LIX, St);
	        {abort_owner, NewOwner} ->
	            listen_loop(Tcp, Owner, LIX, St)
	    end.

Why is the unlink() done before the link()?  I would expect the link()
to be done first, to be paranoid about avoiding detached processes.

If Owner dies, it's an honest race to see if the unlink() happens
before that fact is propagated to the socket process.  If NewOwner
dies before the link(), then the link() should send an 'EXIT' signal
to the socket process.  Hm.  I suppose that's OK.

Come to think of it ... perhaps it's done this way to avoid the tiny
window of opportunity where the socket process is linked to both Owner
and NewOwner, and the death of NewOwner would also kill Owner, and
that would be a bad thing?

-Scott


From maillist@REDACTED  Sun Apr  9 20:39:13 2000
From: maillist@REDACTED (maillist)
Date: Sun, 09 Apr 2000 11:39:13 -0700
Subject: ASN.1 -  ANY, ANY DEFINED BY and EXTERNAL types?
Message-ID: <4.2.2.20000409113520.00a81370@192.168.11.1>



Hi,
from the documentation

http://www.erlang.org/documentation/lib/asn1-1.2.7/doc/html/asn1_ug.html#1.4

it states that these types are not supported in (version 1.03),

I have tried an experiment with the latest version OTP R6B and this seems 
to be
still the case.

has anybody done any work on this or is it something that somebody is
looking at for the future?


regards
Kevin




From costelv@REDACTED  Mon Apr 10 01:42:15 2000
From: costelv@REDACTED (Costel Vrinceanu)
Date: Sun, 9 Apr 2000 16:42:15 -0700 (PDT)
Subject: Subject: Erlang adventures; Erlang image and "success"
Message-ID: <20000409234215.20946.qmail@web304.mail.yahoo.com>

1: Erlang adventures
--------------------
Worked at this company last year on some server box.

After 1.5 failed attempts to get anywhere with it, and
a year of bitching from
my part about trying Erlang on some suitable project,
we finaly got the
manager off our back so 2 of us could spend 8
man-weeks to design, implement
and satisfactorly benchmark 40% of the required
functionality for a product
that was supposed to need 80 man-months.
All this using a platform on which we had epsilon
previous experience.

You think management was impressed?  Nah.  If I were
to shave my butt and
tatoo Java on one hemisphere and Corba on the other,
they would have payed
some sincere attention.

2: Erlang image and "success"
---------------------------------
"Success" in quotes because I think Erlang is very
successfull.
It's not popular though - not because that's a totaly
desirable thing.

People need symbols and images to venerate, keywords
for their resumes and
bumper-stickers and coffee mugs.

Now that VoIp and such is cool and everyone is
drooling at the idea of
replacing and supplementing the circuit-switched
infrastructure with packet-switched and
time-to-market is a major factor in the gold rush for
a slice of the pie ...
Wouldn't now be a good time to hype Erlang beyond
recognition?

It's a gap that needs to be filled.
All the keywords that Erlang supports natively are hot
right in this period
(mucho-nines, fault-tolerance, live code upgrade,
distributed systems, etc)


__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com


From jhague@REDACTED  Mon Apr 10 03:14:03 2000
From: jhague@REDACTED (James Hague)
Date: Sun, 9 Apr 00 20:14:03 -0500
Subject: Subject: Erlang adventures; Erlang image and "success"
Message-ID: <200004100112.UAA07821@node-03.advancenet.net>

>People need symbols and images to venerate, keywords
>for their resumes and
>bumper-stickers and coffee mugs.

Hmmm...I'd get a coffee mug, were one available.  Ericsson was pretty 
coffee-mug happy when I worked there.  I had two training mugs, a couple 
of AXE mugs, one mug for a project that went by the name of "P5," and one 
for an experimental TCP/IP adjunct to AXE called "Gator."  Surely there 
are already a zillion Erlang mugs out there? :)

>Wouldn't now be a good time to hype Erlang beyond
>recognition?

Does hyping a computer language really work?  Okay, it worked for Java 
but did it ever work prior to that?  If you hang out in forums for 
underdog languages--Smalltalk, Forth, Lisp, Scheme, Eiffel, Modula 3, 
Oberon, Haskell, OCaml--there are frequent cries of "Why don't more 
people realize our language is so cool?"  Seems like the best thing for 
Erlang is to just write great applications with it.

James


From Sean.Hinde@REDACTED  Mon Apr 10 10:10:04 2000
From: Sean.Hinde@REDACTED (Sean Hinde)
Date: Mon, 10 Apr 2000 09:10:04 +0100
Subject: New timer app
Message-ID: <402DD461F109D411977E0008C791C312564D60@imp02mbx.one2one.co.uk>

All,

I recently posted a little application derived from the standard timer
module in Kernel which uses an ordered_set mnesia table with a couple of
indeces to give something which is more scalable.

I have two versions of this though, one based on an mnesia table, and one
using three ets tables to do the same.

My question is really which one are people going to find more useful (if at
all ;-))? Pretty much everything I write has a big dollop of mnesia at the
core but I guess that is not the general case?

In fact I think I might have persuaded myself the ets one is better! Views?

Sean


From kenneth@REDACTED  Mon Apr 10 11:06:12 2000
From: kenneth@REDACTED (Kenneth Lundin)
Date: Mon, 10 Apr 2000 11:06:12 +0200
Subject: ASN.1 -  ANY, ANY DEFINED BY and EXTERNAL types?
References: <4.2.2.20000409113520.00a81370@192.168.11.1>
Message-ID: <38F19983.CC8D236B@erix.ericsson.se>

maillist wrote:

> Hi,
> from the documentation
>
> http://www.erlang.org/documentation/lib/asn1-1.2.7/doc/html/asn1_ug.html#1.4
>
> it states that these types are not supported in (version 1.03),
>
> I have tried an experiment with the latest version OTP R6B and this seems
> to be
> still the case.

Yes ANY, ANY DEFINED BY and EXTERNAL is still not supported. When the
development of the
compiler started I took the decision to support the 1994 standard where ANY
and ANY DEFINED BY was removed.
Since then the standards has grown and the whole area iaround ASN.1 is very big
with Information Object Classes,
Parameterization, Constraints , PER etc. and it is very hard to support
everything in those standards. It  is also difficult
to make a choice of what is most important to support next. Therefore my
current strategy is to implement new things
based on what my customers need and based upon the actual ASN.1 specifications
that they want to implement contains.

I have realised that it is necessary to support ANY and other things from the
old 1988 standard at the same time  as
the new stuff because there are quite many specifications based on that
standard that are still interesting.

Currently a preliminary list of planned enhancements and new functionality
looks like this:
- Bugfixes
- Enhanced performance in encode/decode (as always)
- Improved handling of values (necessary)
- Information Object Classes
- PER (unaligned)
- ANY, ANY DEFINED BY
- EXTERNAL ... (I have plans to define  a special module "ASN1" which specifies
EXTERNAL and other "known" types and let the
    compiler  look into that module whenever necessary.

>

If someone else can provide a solution for ANY, ANY DEFINED BY etc. I will be
happy to include it.

>
>
> has anybody done any work on this or is it something that somebody is
> looking at for the future?
>
> regards
> Kevin

regards Kenneth

--
Kenneth Lundin              Ericsson Utvecklings AB
kenneth@REDACTED     ?T2/UAB/F/P
                            BOX 1505
+46 8 727 57 25             125 25 ?lvsj?





From sam@REDACTED  Mon Apr 10 12:37:28 2000
From: sam@REDACTED (Samuel Tardieu)
Date: Mon, 10 Apr 2000 12:37:28 +0200
Subject: Subject: Erlang adventures; Erlang image and "success"
In-Reply-To: <20000409234215.20946.qmail@web304.mail.yahoo.com>; from costelv@yahoo.com on Sun, Apr 09, 2000 at 04:42:15PM -0700
References: <20000409234215.20946.qmail@web304.mail.yahoo.com>
Message-ID: <2000-04-10-12-37-28+trackit+sam@inf.enst.fr>

On  9/04, Costel Vrinceanu wrote:

| It's not popular though - not because that's a totaly
| desirable thing.

We came to the same conclusion some years ago in an Ada group: if we call the
next revision of Ada (2005?) Java++, everyone will start doing Ada... That's
scaring.

As far as Erlang, Ada or Python (my 3 favourite languages) are concerned, I
much prefer to convince people based on technical grounds rather than on
flashy things. However, I have to admit that the application monitor helps
*A LOT* to illustrate fault-tolerance capacities of Erlang. I think the
only thing Erlang and Ada lack are *graphical* killer applications.

My advice would be: people, if you build a complex system in Erlang, take
a small part of the time you have freed by using Erlang to build a graphical
monitoring of your application. It works.



From etxuwig@REDACTED  Mon Apr 10 13:09:30 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Mon, 10 Apr 2000 13:09:30 +0200 (MET DST)
Subject: Subject: Erlang adventures; Erlang image and "success"
In-Reply-To: <2000-04-10-12-37-28+trackit+sam@inf.enst.fr>
Message-ID: <Pine.GSO.4.10.10004101251140.9715-100000@avc303>

On Mon, 10 Apr 2000, Samuel Tardieu wrote:

sam>My advice would be: people, if you build a complex system in
sam>Erlang, take a small part of the time you have freed by using
sam>Erlang to build a graphical monitoring of your application. It
sam>works.

Yes, this reminds me of Martin Wikborg telling me of the thesis
project to write an army troop movement simulator in Erlang.
They spent 6-7 weeks (I think) writing the actual simulator, and then
quickly pasted together a GUI for the purposes of the demo. Almost all
the audience's attention during the demo was focused at the GUI...

I've had similar painful experiences -- the most flagrant being one
where I demo:ed a decision support system in Dubai. It had a decent
enough GUI, but the guy in the booth next to me (Admiral Systems,
Inc.) had a simulation tool with a *suberb* GUI. My explanation that
"this is live, that is Memorex" didn't seem to cut mustard. All
the customers saw was the GUI.

So, yes, it's all too easy to think that the customer will realise
the magic that goes on behind the scenes -- very few of them will.
You have to make it visible.

/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44



From sam@REDACTED  Mon Apr 10 17:16:59 2000
From: sam@REDACTED (Samuel Tardieu)
Date: 10 Apr 2000 17:16:59 +0200
Subject: New timer app
In-Reply-To: Sean Hinde's message of "Mon, 10 Apr 2000 09:10:04 +0100"
References: <402DD461F109D411977E0008C791C312564D60@imp02mbx.one2one.co.uk>
Message-ID: <2000-04-10-17-16-59+trackit+sam@inf.enst.fr>

>>>>> "Sean" == Sean Hinde <Sean.Hinde@REDACTED> writes:

Sean> I have two versions of this though, one based on an mnesia
Sean> table, and one using three ets tables to do the same.

If I remember well (I've seen something like this in the release
notes), ordered sets in Mnesia have to be kept in RAM, right? If this
is still the case, I think the ets version may be more lightweight.

  Sam
-- 
Samuel Tardieu -- sam@REDACTED



From vances@REDACTED  Mon Apr 10 20:23:59 2000
From: vances@REDACTED (Vance Shipley)
Date: Mon, 10 Apr 2000 14:23:59 -0400
Subject: Subject: Erlang adventures; Erlang image and "success"
In-Reply-To: <200004100112.UAA07821@node-03.advancenet.net>
Message-ID: <NBBBIOHCCJPPDNIBBIKCCENOCCAA.vances@motivity.ca>

}  Hmmm...I'd get a coffee mug, were one available.  ...
}  Surely there are already a zillion Erlang mugs out there? :)

I have one.  :)
 
	-Vance


From kurt.wilkin@REDACTED  Thu Apr 13 02:05:56 2000
From: kurt.wilkin@REDACTED (Kurt)
Date: Thu, 13 Apr 2000 12:05:56 +1200
Subject: newbie q.
References: <Pine.GSO.4.10.10001280943280.27234-100000@avc303>
Message-ID: <38F50F64.B8E85337@actfs.co.nz>

Greetings all.
Given this:
 
adder = fun(X) -> fun(Y) -> X + Y end end.

I can do this : 
Adder3 = adder(3).
and Adder3(10) returns 13.

However I can also do this: 
AdderX = adder(Adder3).

So, how can I call AdderX ? Is it possible? 
When I do AdderX(5), is this trying to do: Adder3 + 5
which is an error, but is syntactically correct?
Or have I got so used to pedantic type checking that I
don't even realise when I'm being lazy anymore?

Also, if `->' is `returns' (is it?), 
what does the '=' in the declaration mean?


Thanks.


From thomas@REDACTED  Thu Apr 13 08:40:03 2000
From: thomas@REDACTED (Thomas Arts)
Date: Thu, 13 Apr 2000 08:40:03 +0200
Subject: newbie q.
References: <Pine.GSO.4.10.10001280943280.27234-100000@avc303> <38F50F64.B8E85337@actfs.co.nz>
Message-ID: <38F56BC3.AEAC2D63@cslab.ericsson.se>

Kurt wrote:
> 
> Greetings all.
> Given this:
> 
> adder = fun(X) -> fun(Y) -> X + Y end end.

I guess you mean
Adder =  fun(X) -> fun(Y) -> X + Y end end.

Since "adder" without a capital is an atom and in that sense
you try to match an atom with a function, which fails.
In case of "Adder" with a capital, Adder is a variable and 
you try to match the variable with the function. If Adder has
not yet been asigned a value, this match is an assignment for
Adder to become placeholder for the function definition.

> I can do this :
> Adder3 = adder(3).
> and Adder3(10) returns 13.

This match is equivalent to
Adder3 = fun(Y) -> 3 + Y end.

> However I can also do this:
> AdderX = adder(Adder3).

which is equivalent to
AdderX = fun(Y) -> (fun(Z) -> 3+Z end) + Y end.

> So, how can I call AdderX ? Is it possible?

sure you can call this AdderX and it will give exactly the
right result:
Error: badarith

AdderX(5) results in an attempt to add 5 to a function.
This is not possible, hence the error message.

> When I do AdderX(5), is this trying to do: Adder3 + 5
> which is an error, but is syntactically correct?

Sure, the syntax permits more than what is computational
possible. As in most languages. The syntax for example allows
to write 2/0, but most languages give up on this.

It's not really the nicest type error you could hope for, but you
are at least warned for doing something strange instead of
having a runtime system that assumes the value to be 0 and continues
computation ;0).

/Thomas


From etxuwig@REDACTED  Thu Apr 13 15:33:43 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Thu, 13 Apr 2000 15:33:43 +0200 (MET DST)
Subject: New timer app
In-Reply-To: <402DD461F109D411977E0008C791C312564D60@imp02mbx.one2one.co.uk>
Message-ID: <Pine.GSO.4.10.10004131524140.7451-200000@avc303>

On Mon, 10 Apr 2000, Sean Hinde wrote:

Sean>All,
Sean>
Sean>I recently posted a little application derived from the
Sean>standard timer module in Kernel which uses an ordered_set
Sean>mnesia table with a couple of indeces to give something
Sean>which is more scalable.
Sean>
Sean>I have two versions of this though, one based on an mnesia
Sean>table, and one using three ets tables to do the same.
Sean>
Sean>My question is really which one are people going to find
Sean>more useful (if at all ;-))? Pretty much everything I write
Sean>has a big dollop of mnesia at the core but I guess that is
Sean>not the general case?
Sean>
Sean>In fact I think I might have persuaded myself the ets one is
Sean>better! Views?

I must have dozed off for a while -- I didn't realize what you'd 
done until now.

At AXD 301, we have forbidden use of the timer module, and recommend
using our own module, sysTimer. The reason is that timer.erl is
very inefficiently implemented. We discovered that it was much
(rougly 10x) cheaper to use the classic schoolbook example:

send_after(Time, Msg) ->
  spawn_link(?MODULE, do_send_after, [self(), Time, Msg]).

do_send_after(Pid, Time, Msg) ->
   receive
   after Time ->
      Pid ! {timeout, self(), Msg}
   end.

Since then, OTP has implemented support for timers as BIFs, and
our sysTimer module now uses the BIFs instead.

I've attached our sysTimer module for your perusal.
Note that it contains some other functions, like
send_after_specified(DateTime). It is not API-compatible with
timer.erl, and uses a special mnesia table for "logical timers".
If you want to use it, you can rewrite parts to make it run outside of
AXD 301.

/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44
-------------- next part --------------
%%% #--------------------------------------------------------------------------
%%% #0.    BASIC INFORMATION
%%% #--------------------------------------------------------------------------
%%% %CCaseFile:	sysTimer.erl %
%%% Description: Handles system timers. See MID sysTimer_MID.fm
%%%              for information.
%%%              However, note that all functions in sysTimer uses
%%%              utc (universal time). This means that all specified
%%%              times must be specified in utc when calling sysTimer.
%%%              Currently, there is no support for converting
%%%              local time to universal time (day-live saving ..)
%%%              in sysTimer or in OTP.
%%%
%%% Modules used:  mnesia, calendar, erlang, sysTimezone
%%% ----------------------------------------------------------

-module(sysTimer).
%-behaviour(timer).
-id('19/190 55-CNA 121 70').
-vsn('/main/Inc3/Inc4/Inc5/R2A/R3B/R4A/R6A/3').
-date('99-10-05').
-author('etxtopi').


%%% ----------------------------------------------------------
%%% Template Id: ETX/B 00201 - 19055/1 Rev C
%%%
%%% #Copyright (C) 1996
%%% by ERICSSON TELECOM AB
%%% S - 125 26  STOCKHOLM
%%% SWEDEN, tel int + 46 8 719 0000
%%% 
%%% The program may be used and/or copied only with the written permission from
%%% ERICSSON TELECOM AB, or in accordance with the terms and conditions
%%% stipulated in the agreement/contract under which the program has been
%%% supplied.
%%%   
%%% All rights reserved.
%%% 
%%%
%%% #--------------------------------------------------------------------------
%%% #1.    REVISION LOG
%%% #--------------------------------------------------------------------------
%%% Rev      Date       Name        What
%%% -----    -------    --------    --------------------------
%%% PA1      960814     epkolso     Created.
%%% PA2      960815     etxberb     Correction.
%%% PA3      960816     etxberb     System messages added.
%%% PA4      960819     etxberb     An mnesia-read operation added to function
%%%                                 start_server/1.
%%% PA5      960822     etxberb     The return value from function start_server
%%%                                 changed to {ok,Pid}.
%%% PA6      960829     etxberb     SYS_DEBUG added.
%%% PA7      960916     epkolso     Changed module name to sysTimer.
%%%                                 Added start_interval.
%%%                                 Took out all ugly mnesia reads and
%%%                                 system dependent stuff to make it more
%%%                                 general, useful, and beautiful.
%%% PA8      961016     epkulwi     Added sleep, apply_after, etc.
%%%                                 Changed names and certain behavior.
%%% PA9      970304     epkulwi     Changed behaviour of xxx_interval,
%%%                                 Added sysTimeout().
%%% Inc4/1   970617     etxuwig     Changed apply_interval to be exact.
%%% Inc4/4   970901     etxtryd     Added apply_timer_specified
%%% Inc4/6   970910     etxtryd     Test before spwn in apply_timer_specified
%%% Inc4/7   970911     etxtryd     export wait_a_day
%%% Inc4/8   970914     etxtryd     Updates comments by etxuwig
%%% Inc4/9   971111     etxtryd     Added send_after_specified
%%% Inc4/10  971203     etxtryd     Uses utc instead of local time.
%%% Inc5/1   980130     etxtopi     Added convert_2utc
%%% Inc5/2   980505     etxtopi     convert_2utc calls erlang
%%% R2A/1    980507     etxuwig     changed dirty_read() to ets:lookup()
%%% R3B/2    981007     etxtopi     convert_2utc has to entries now.
%%% R3B/4    981103     etxuwig     added put() statements for debugging
%%% R3B/5    981106     etxuwig     timer BIFs, code_change in interval timers
%%% R6A/1    990614     etxtryd     changed to dirty_read() from ets:lookup() 
%%% R6A/2    990705     etxtryd     ets:lookup() back again
%%% R6A/3    991004     etxtopi     New convert_2utc
%%% #--------------------------------------------------------------------------
%%% #2.    EXPORT LISTS
%%% #--------------------------------------------------------------------------
%%% #2.1   EXPORTED INTERFACE FUNCTIONS
%%% #--------------------------------------------------------------------------

-export([send_after/2,
	 send_after_specified/2,
         send_interval/2,
         apply_after/4,
         apply_after_specified/4,
         apply_interval/4,
	 convert_2utc/2,
	 convert_2utc/1,
	 cancel/1,
         sleep/1,
         set_value/2,    
         get_value/1,
         system_time/0]).

-export([sysTimeout/0]).

%%% #--------------------------------------------------------------------------
%%% #2.2   EXPORTED INTERNAL FUNCTIONS
%%% #--------------------------------------------------------------------------
-export([do_send_after/3,
	 do_send_interval/3,
         do_apply_after/5,
	 do_apply_after_specified/5,
         do_apply_interval/6,
	 wait_a_day/3,
	 wait_a_day/5]).

%%% #--------------------------------------------------------------------------
%%% #2.3   DEFINITION OF CONSTANTS
%%% #--------------------------------------------------------------------------

-include("sysDefines.hrl").


-record(sysTimer, {key, value}).

%%% #--------------------------------------------------------------------------
%%% #2.4   DEFINITION OF CONSTANTS AS MACROS
%%% #--------------------------------------------------------------------------

%%% #--------------------------------------------------------------------------
%%% #3.    CODE
%%% #--------------------------------------------------------------------------
%%% #3.1   CODE FOR EXPORTED INTERFACE FUNCTIONS
%%% #--------------------------------------------------------------------------

%%%----------------------------------------------------------------------
%%% -type sysTimeout()->
%%%     integer().
%%% Input: -
%%% Output: Value
%%% Exceptions: 
%%% Description: Reads the value stored as sysTimeout in Mnesia,
%%%              or returns a hardcoded default.
%%%----------------------------------------------------------------------
sysTimeout() ->
    case catch ets:lookup(sysTimer, sysTimeout) of
	[#sysTimer{value = Time}] ->
		Time;
	 _ ->
		10000
	end.

%%%----------------------------------------------------------------------
%%% -type set_value(Name : atom(), Time : integer())->
%%%     term().
%%% Input: Name, Time
%%% Output: ok
%%% Exceptions: Exits if Mnesia isn't running.
%%% Description: Sets named timer Name to timeout value Time.
%%%              Specifically, it stores the relation in the Mnesia
%%%              table sysTimer (which it creates if it isn't there.)
%%%----------------------------------------------------------------------
set_value(Name, Time) when atom(Name), integer(Time), Time >= 0 ->
    ok = verify_table(),
    mnesia:dirty_write(#sysTimer{key = Name, value = Time}).


get_value(Name) ->
    case ets:lookup(sysTimer, Name) of
	[#sysTimer{value = Time}] ->
	    Time;
	_ ->
	    exit(undef)
    end.

%%%----------------------------------------------------------------------
%%% -type send_after(TimerSpec : term(), Msg : term())->
%%%     term().
%%% Input: TimerSpec, Msg
%%% Output: Key
%%% Exceptions: Exit if named timer hasn't been defined.
%%% Description: TimerSpec specifies the timeout value, either
%%%              indirectly by name or directly in milliseconds.
%%%              Send a message after timeout given by TimerSpec.
%%%              The format of the message is {timeout, Key, Msg}.
%%%----------------------------------------------------------------------
%send_after(Time, Msg) when integer(Time) ->
%    spawn_link(sysTimer,do_send_after,[Time, self(), Msg]);
%send_after(Name, Msg) ->
%    spawn_link(sysTimer, do_send_after, [get_value(Name), self(), Msg]).

send_after(Time, Msg) when integer(Time) ->
    erlang:start_timer(Time, self(), Msg);
send_after(Name, Msg) ->
    erlang:start_timer(get_value(Name), self(), Msg).

%%%----------------------------------------------------------------------
%%% -type send_after_specified(TimerSpec : {{year, month, day},
%%%                            {hour, minute, second}}, Msg : term()) ->
%%%     term().
%%% Input: TimerSpec (all values are integers), Msg
%%% Output: Key | invalid_timer_specified
%%% Exceptions: -
%%% Description: Send a message after timeout given by TimerSpec.
%%%              The format of the message is {timeout, Key, Msg}.
%%%              TimerSpec is specified in calender:universal_time()
%%%              format.
%%%----------------------------------------------------------------------
send_after_specified({{SYear,SMonth,SDay}, {SHour, SMin, SSec}}, Msg) ->
    case calendar:time_difference(calendar:universal_time(),
				  {{SYear,SMonth,SDay},
				   {SHour, SMin, SSec}}) of
	{DDate, {DHour, DMin, DSec}} ->
	    if
		DDate < 0 -> % Faulty timer specified
		    invalid_timer_specified;
		DDate == 0 -> % Same day
		    Time = ((DHour*3600) + (DMin*60) + DSec) * 1000,
		    send_after(Time, Msg);
%		    spawn_link(sysTimer,
%			       do_send_after, [Time, self(), Msg]);
		DDate > 0 -> % Start by waiting a day
		    spawn_link(sysTimer, wait_a_day,
			       [{{SYear,SMonth,SDay}, {SHour, SMin, SSec}},
				Msg, self()])
	    end
    end;
send_after_specified(FaultyTimeSpecified, Msg) ->
    invalid_timer_specified.


%%%----------------------------------------------------------------------
%%% -type send_interval(TimerSpec : term(), Msg : term())->
%%%     term().
%%% Input: TimerSpec, Msg
%%% Output: Key
%%% Exceptions: Exit if named timer hasn't been started.
%%% Description: TimerSpec specifies the timeout value, either
%%%              indirectly by name or directly in milliseconds.
%%%              Send a message at intervals given by TimerSpec.
%%%              The message sent is {timeout, Key, Msg}.
%%%              If Time is a logical Timer name, the timer thread
%%%              will re-read the actual timer value at each interval.
%%%              Thus, a call to sysTimer:set_value(Name, Value) will
%%%              be reflected in each running interval thread which
%%%              uses that logical timer.
%%%----------------------------------------------------------------------
%send_interval(Time, Msg) when integer(Time) ->
%    spawn_link(sysTimer,do_send_interval,[Time, self(), Msg]);
send_interval(NameOrTime, Msg) ->
    spawn_link(sysTimer, do_send_interval, [NameOrTime, self(), Msg]).

%%%----------------------------------------------------------------------
%%% -type cancel(Key : term())->
%%%     term().
%%% Input: Key
%%% Output: ok
%%% Exceptions: 
%%% Description: Cancels timer request identified by Key.
%%%              If the timeout message has already been sent, it is
%%%              removed from the message queue.
%%%----------------------------------------------------------------------
cancel(Pid) when pid(Pid) ->
    unlink(Pid),
    exit(Pid, kill),
    receive
	{timeout, Pid, _} ->
	    ok
    after 0 ->
	    ok
    end;
cancel(TimerRef) ->
    case erlang:cancel_timer(TimerRef) of
	false ->
	    receive
		{timeout, TimerRef, _} ->
		    ok
	    after 0 ->
		    ok
	    end;
	_ ->
	    ok
    end.

%%%----------------------------------------------------------------------
%%% -type apply_after(TimerSpec : term(), 
%%%                   M : atom(), F : atom(), A : list())->
%%%     term().
%%% Input: TimerSpec, Module, Function, Args
%%% Output: Key
%%% Exceptions: 
%%% Description: Apply function {Module, Function, Args} after Time.
%%%              This call is made from within a separate process.
%%%----------------------------------------------------------------------
apply_after(Time, M, F, A) when integer(Time) ->
    spawn_link(sysTimer, do_apply_after, [Time, M, F, A, self()]);
apply_after(Name, M, F, A) ->
    spawn_link(sysTimer, do_apply_after, [get_value(Name), M, F, A, self()]).


%%%----------------------------------------------------------------------
%%% -type apply_after_specified(TimerSpec : {{year, month, day},
%%%                            {hour, minute, second}}, M : atom(),
%%%                            F : atom(), A : list())->
%%%     term().
%%% Input: TimerSpec (all values are integers), Module, Function, Args
%%% Output: Key | invalid_timer_specified | already_expired
%%% Exceptions: 
%%% Description: Apply function {Module, Function, Args} when the 
%%%              current time (calendar:universal_time() is equal to the
%%%              specified TimerSpec.
%%%              This call is made from within a separate process.
%%%----------------------------------------------------------------------
apply_after_specified({{SYear,SMonth,SDay}, {SHour, SMin, SSec}}, M, F, A) ->
    case calendar:time_difference(calendar:universal_time(),
				  {{SYear,SMonth,SDay}, 
				   {SHour, SMin, SSec}}) of
	{DDate, {DHour, DMin, DSec}} ->
	    if
		DDate < 0 -> % Faulty timer specified
		    already_expired;
		DDate == 0 -> % Same day
		    Time = ((DHour*3600) + (DMin*60) + DSec) * 1000,
%		    spawn_link(sysTimer, do_apply_after, [Time, M, F, A,
%							  self()]);
		    apply_after(Time, M, F, A);
		DDate > 0 -> % Start by waiting a day
		    spawn_link(sysTimer, wait_a_day,
			       [{{SYear,SMonth,SDay}, {SHour, SMin, SSec}},
				M, F, A, self()])
	    end
    end;
apply_after_specified(FaultyTimeSpecified, M, F, A) ->
    invalid_timer_specified.

%%%----------------------------------------------------------------------
%%% -type apply_interval(Time : integer(), 
%%%                      M : atom(), F : atom(), A : list())->
%%%     term().
%%% Input: Time, Module, Function, Args
%%% Output: Key
%%% Exceptions: 
%%% Description: Apply function {Module, Function, Args} repeatedly
%%%              after Time.
%%%              This call is made from within a separate process.
%%%              The timer makes sure that the interval stays exact
%%%              relative to the start time. If the applied function 
%%%              doesn't return until an interval has been passed, the 
%%%              timer will wait until the next interval.
%%%              If Time is a logical Timer name, the timer thread
%%%              will re-read the actual timer value at each interval.
%%%              Thus, a call to sysTimer:set_value(Name, Value) will
%%%              be reflected in each running interval thread which
%%%              uses that logical timer.
%%%----------------------------------------------------------------------
%apply_interval(Time, M, F, A) when integer(Time) ->
%    Pid = spawn_link(sysTimer, do_apply_interval, 
%		[Time, M, F, A]);
apply_interval(NameOrTime, M, F, A) ->
    Now = erlang:now(),
    Pid = spawn_link(sysTimer, do_apply_interval, 
		[NameOrTime, Now, Now, M, F, A]).


sleep(Time) ->
    receive
    after Time ->
	    ok
    end.

%%%----------------------------------------------------------------------
%%% -type convert_2utc(Date : term(), Time : term())->
%%%     term().
%%% Input: {YYYY,MM,DD},{HH,MM,SS}
%%% Output: {{NewDate}, {NewTime}}
%%% Exceptions: -
%%% Description: Converts the localtime to the corresponding UTC-time
%%% (universal_time). This method does not use local_time_to_universal_time
%%% which gives you faulty results when using non-existing times (eg.
%%% a time in the "DST/STD gap").
%%%
%%%----------------------------------------------------------------------
convert_2utc(Date, Time) ->
     convert_2utc({Date, Time}).

convert_2utc({Date, Time}) ->
    %% stolen from lole
    D1 = calendar:datetime_to_gregorian_seconds(calendar:local_time()),
    D2 = calendar:datetime_to_gregorian_seconds({Date, Time}),
    Diff = D2-D1,
    D3 = calendar:datetime_to_gregorian_seconds(calendar:universal_time()),
    D4 = D3+Diff,
    calendar:gregorian_seconds_to_datetime(D4).

%%%
%%% return the system time in
%%% milli-seconds.
%%%
system_time() ->
    {M,S,U} = erlang:now(), 
    1000000000 * M + 1000 * S + (U div 1000).

%%
%% Calculate difference between two timestamps.
%% It's important to avoid using bignums (>16#FFFFFF).
%%
diff({M,S,U}, {M,S1,U1}) ->
    ((S-S1) * 1000) + ((U-U1) div 1000);
diff({M,S,U}, {M1,S1,U1}) ->
    ((M-M1)*1000000+(S-S1))*1000 + ((U-U1) div 1000).

%%
%% add(Time, Timestamp) -> Timestamp1
%%   This function adds Time milliseconds to a 
%%   timestamp and returns a new timestamp.
%%   This is used by apply_interval to maintain
%%   constant intervals. Timestamp1 should always
%%   be of type (StartTime + N*Time).
%%
add(Time, {M,S,U}) ->
    U1 = (U + Time * 1000),
    S1 = (S + (U1 div 1000000)),
    {M + S1 div 1000000, 
     S1 rem 1000000, 
     U1 rem 1000000}.

%%
%% sleep_time(Time, Acc) -> {TimeToSleep, Acc1}
%%   Time ::= timeout in milliseconds
%%   Acc  ::= accumulated timestamp
%%   This function adds Time to Acc and calculates
%%   how many milliseconds remain to Acc1. 
%%   Assuming that Time is constant Acc1 will always
%%   be the next (StartTime + N*Time) in the future,
%%   that is, an interval may be skipped for whatever
%%   reason, and sleep_time/2 will keep up.
%%
sleep_time(Time, Acc) ->
    Acc1 = add(Time, Acc),
    case diff(Acc1,erlang:now()) of
	N when N > 0 ->
	    {normal, N, Acc1};
	Less ->
	    Time1 = Time * ((-Less div Time)+1),
	    {skip, Time1 + Less, add(Time1+Time, Acc)}
    end.

%%% #--------------------------------------------------------------------------
%%% #3.2   CODE FOR EXPORTED INTERNAL FUNCTIONS
%%% #--------------------------------------------------------------------------

do_send_after(Time, Pid, Msg) ->
    put(arguments, [Time, Pid, Msg]),
    receive
    after Time ->
	    Pid ! {timeout, self(), Msg},
	    unlink(Pid)
    end.

do_send_interval(Time, Pid, Msg) when integer(Time) ->
    put(arguments, [Time, Pid, Msg]),
    receive
    after Time ->
	    Pid ! {timeout, self(), Msg},
	    ?MODULE:do_send_interval(Time, Pid, Msg)
    end;
do_send_interval(Name, Pid, Msg) ->
    put(arguments, [Name, Pid, Msg]),
    Time = get_value(Name),
    receive
    after Time ->
	    Pid ! {timeout, self(), Msg},
	    ?MODULE:do_send_interval(Name, Pid, Msg)
    end.

do_apply_after(Time, M, F, A, LinkedPid) ->
    put(arguments, [Time, M, F, A, LinkedPid]),
    receive
    after Time ->
            apply(M, F, A),
	    unlink(LinkedPid)
    end.


wait_a_day(SpecifiedTime, M, F, A, LinkedPid) ->
    put(arguments, [SpecifiedTime, M, F, A, LinkedPid]),
    receive
    after (24*3600*1000) ->  % One day in milliseconds
	    do_apply_after_specified(SpecifiedTime, M, F, A, LinkedPid)
    end.

wait_a_day(SpecifiedTime, Msg, UserPid) ->
    put(arguments, [SpecifiedTime, Msg, UserPid]),
    receive
    after (24*3600*1000) ->  % One day in milliseconds
	    do_send_after_specified(SpecifiedTime, Msg, UserPid)
    end.

do_apply_after_specified(SpecifiedTime, M, F, A, LinkedPid) ->
    put(arguments, [SpecifiedTime, M, F, A, LinkedPid]),
    case calendar:time_difference(calendar:universal_time(), SpecifiedTime) of
	{Date, {Hour, Min, Sec}} ->
	    if
		Date == 0 -> % Same day
		    Time = ((Hour*3600) + (Min*60) + Sec) * 1000,
		    do_apply_after(Time, M, F, A, LinkedPid);
		Date > 0 -> % Day in the future
		    wait_a_day(SpecifiedTime, M, F, A, LinkedPid);
		Date < 0 ->
		    % This clause can occur if the SpecifiedTime is
		    % day(s) + 1 (or some) second and the load is
		    % very high.
		    do_apply_after(1, M, F, A, LinkedPid)
	    end
    end.

do_send_after_specified(SpecifiedTime, Msg, UserPid) ->
    put(arguments, [SpecifiedTime, Msg, UserPid]),
    case calendar:time_difference(calendar:universal_time(), SpecifiedTime) of
	{Date, {Hour, Min, Sec}} ->
	    if
		Date == 0 -> % Same day
		    Time = ((Hour*3600) + (Min*60) + Sec) * 1000,
		    do_send_after(Time, UserPid, Msg);
		Date > 0 -> % Day in the future
		    wait_a_day(SpecifiedTime, Msg, UserPid);
		Date < 0 ->
		    % This clause can occur if the SpecifiedTime is 
		    % day(s) + 1 (or some) second and the load is
		    % very high.
		    do_send_after(1, Msg, UserPid)
	    end
    end.


do_apply_interval(Time, Start, Acc, M, F, A) when integer(Time) ->
    put(arguments, [Time, Start, Acc, M, F, A]),
    {Mode, Sleep, Acc1} = sleep_time(Time, Acc),
    receive
    after Sleep ->
            apply(M, F, A),
	    ?MODULE:do_apply_interval(Time, Start, Acc1, M, F, A)
    end;
do_apply_interval(Name, Start, Acc, M, F, A) ->
    put(arguments, [Name, Start, Acc, M, F, A]),
    Time = get_value(Name),
    {Mode, Sleep, Acc1} = sleep_time(Time, Acc),
    receive
    after Sleep ->
            apply(M, F, A),
            ?MODULE:do_apply_interval(Name, Start, Acc1, M, F, A)
    end.

%%% #--------------------------------------------------------------------------
%%% #3.3   CODE FOR INTERNAL FUNCTIONS
%%% #--------------------------------------------------------------------------
verify_table() ->
    case catch mnesia:table_info(sysTimer, name) of
	{'EXIT', _} ->
	    case catch mnesia:system_info(db_nodes) of
		{'EXIT', _} ->
		    exit({error, mnesia_not_running});
		Nodes ->
		    {atomic, ok} = 
			mnesia:create_table([{name, sysTimer},
					     {disc_copies, Nodes},
					     {attributes, [key, value]}]),
		    ok
	    end;
	_ ->
	    ok
    end.



%%% #--------------------------------------------------------------------------
%%% #4     CODE FOR TEMPORARY CORRECTIONS
%%% #--------------------------------------------------------------------------


%%% ----------------------------------------
%%% end of sysTimer.erl

From Sean.Hinde@REDACTED  Thu Apr 13 20:55:21 2000
From: Sean.Hinde@REDACTED (Sean Hinde)
Date: Thu, 13 Apr 2000 19:55:21 +0100
Subject: ClearCase and such like
Message-ID: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk>

All,

I'm thinking of buying a clever build management tools such as Rational
ClearCase.

Does anyone have much experience of using these tools in an Erlang
development environment. i.e. nice integration with emacs, and integration
with the OTP directory structure, but also with some powerful features like
parallel builds and checkpoint builds etc?

Particularly I'd like to hear if anyone has had to do large customisations
of these tools to make them fit.

Thanks very much,

Sean


From Sean.Hinde@REDACTED  Thu Apr 13 21:00:20 2000
From: Sean.Hinde@REDACTED (Sean Hinde)
Date: Thu, 13 Apr 2000 20:00:20 +0100
Subject: New timer app
Message-ID: <402DD461F109D411977E0008C791C312564D7A@imp02mbx.one2one.co.uk>

Uffe,

Thanks very much for the sysTimer module example. Just goes to show how one
persons optimisation is anothers example..

> If you want to use it, you can rewrite parts to make it run outside of
> AXD 301.

I notice that there are dire Ericsson copyright warnings all over the header
of the sysTimer file. This raises the question of what should we be putting
as the header on erlang code we publish to protect all from misuse, allow
freedom to change etc etc.

The guys from erlang.org suggested the EPL, which seems good. Most of the
files in the contributions have little or no header or ownership info
though.

Views?

Sean



From sam@REDACTED  Thu Apr 13 21:44:31 2000
From: sam@REDACTED (Samuel Tardieu)
Date: Thu, 13 Apr 2000 21:44:31 +0200
Subject: New timer app
In-Reply-To: <402DD461F109D411977E0008C791C312564D7A@imp02mbx.one2one.co.uk>; from Sean.Hinde@one2one.co.uk on Thu, Apr 13, 2000 at 08:00:20PM +0100
References: <402DD461F109D411977E0008C791C312564D7A@imp02mbx.one2one.co.uk>
Message-ID: <2000-04-13-21-44-31+trackit+sam@inf.enst.fr>

On 13/04, Sean Hinde wrote:

| The guys from erlang.org suggested the EPL, which seems good. Most of the
| files in the contributions have little or no header or ownership info
| though.

Every license has its pros and its cons. As far as I am concerned, I
choose the GPL whenever I want to make sure that my code will never
be part of a closed-source application and the BSD license when I don't care
if people use it in their application even if they do not want to release
the source, for whatever reason (one may be that this is just impractical).

  Sam



From hal@REDACTED  Fri Apr 14 06:08:53 2000
From: hal@REDACTED (Hal Snyder)
Date: 13 Apr 2000 23:08:53 -0500
Subject: ClearCase and such like
In-Reply-To: Sean Hinde's message of "Thu, 13 Apr 2000 19:55:21 +0100"
References: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk>
Message-ID: <87itxlwch6.fsf@ghidra.vail>

Sean Hinde <Sean.Hinde@REDACTED> writes:

> I'm thinking of buying a clever build management tools such as
> Rational ClearCase.
> 
> Does anyone have much experience of using these tools in an Erlang
> development environment. i.e. nice integration with emacs, and
> integration with the OTP directory structure, but also with some
> powerful features like parallel builds and checkpoint builds etc?
> 
> Particularly I'd like to hear if anyone has had to do large
> customisations of these tools to make them fit.
> 
> Thanks very much,
> 
> Sean

I remember reading that Ericsson uses ClearCase for in-house version
control. I have worked at installations using ClearCase and others
using DSEE (ancestor of ClearCase), CVS, etc. I'd rather flip burgers
than deal with ClearCase on a daily basis again; to me it seemed a
slow, bloated, overpriced resource hog and an administrative
sinkhole.

YMMV, I know there are competent professionals who actually like
ClearCase.

At one point at a site where they used ClearCase we had two
contractors on site full time from Rational and got involved over
several days in lengthy and increasingly existential discussions about
the feasibility of distributed repositories over WAN connections.
Something the free software guys do every day on a shoestring without
even thinking about it.

Sorry for the rant. I think the growth of the Erlang as an open
platform is a wonderful thing. Coolness factors: Erlang, +10;
ClearCase, 0.


From klacke@REDACTED  Fri Apr 14 09:28:00 2000
From: klacke@REDACTED (Klacke)
Date: Fri, 14 Apr 2000 09:28:00 +0200
Subject: ClearCase and such like
In-Reply-To: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk>
References: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk>
Message-ID: <20000414092800.A56293@bluetail.com>

On Thu, Apr 13, 2000 at 07:55:21PM +0100, Sean Hinde wrote:
> All,
> 
> I'm thinking of buying a clever build management tools such as Rational
> ClearCase.
> 
> Does anyone have much experience of using these tools in an Erlang
> development environment. i.e. nice integration with emacs, and integration
> with the OTP directory structure, 


While at Ericsson, I (and everybody else) was running ClearCase, here
at Bluetail we're running the whole show in cvs, and I must say that
I prefer cvs. Primary reason is that I understand what's going on.

As for emacs integration, there are emacs modes both for cvs as well 
as for ClearCase which do similar stuff.


/klacke


-- 
Claes Wikstrom                          <klacke@REDACTED>
Bluetail AB                             http://www.bluetail.com




From bud@REDACTED  Thu Apr 13 00:44:41 2000
From: bud@REDACTED (Bud P. Bruegger)
Date: Thu, 13 Apr 2000 00:44:41 +0200
Subject: ClearCase and such like
In-Reply-To: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co
 .uk>
Message-ID: <3.0.6.32.20000413004441.008a9100@mail.sistema.it>

Has any of you looked at Aegis
(http://freshmeat.net/appindex/1998/07/08/899909564.html)?  

Haven't used it yet, but the reading I did on it and some discussion with
Peter Miller, the author, made it look VERY attractive.

--bud
/------------------------------------------------------------------------\
| Bud P. Bruegger, Ph.D.  |  mailto:bud@REDACTED                       |
| Sistema                 |  http://www.sistema.it                       |
| Information Systems     |  voice general: +39-0564-418667              |
| Via U. Bassi, 54        |  voice direct:  +39-0564-418667 (internal 41)|
| 58100 Grosseto          |  fax:           +39-0564-426104              |
| Italy                   |  P.Iva:         01116600535                  |
\------------------------------------------------------------------------/


From Sean.Hinde@REDACTED  Fri Apr 14 10:51:42 2000
From: Sean.Hinde@REDACTED (Sean Hinde)
Date: Fri, 14 Apr 2000 09:51:42 +0100
Subject: ClearCase and such like
Message-ID: <402DD461F109D411977E0008C791C312564D7C@imp02mbx.one2one.co.uk>

An interesting set of views! I'll see what the man from Rational has to say
today.

I'm struggling to see how cvs and ilk allow one to take an application off
in a couple of experimental directions without taking the main source tree
off the rails, and then use the best bits in a clever merge.

ClearCase claims to manage this sort of thing quite well..?

Sean


From chris.williams@REDACTED  Fri Apr 14 11:03:12 2000
From: chris.williams@REDACTED (Chris Williams)
Date: Fri, 14 Apr 2000 10:03:12 +0100
Subject: ClearCase and such like
References: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk>
Message-ID: <38F6DED0.BA2C6510@ericsson.com>

Hi 
We here at EA910 in Ireland have been using ClearCase for the last on
and a half 
year with good results from a user perspective at development and
builds.
We have the whole of our target environment and tools and code in
clearcase.
Worth noting is that having the tools in clearcase make things slow but 
it has the advantage  that all our sites can use the same tools as we
use multisite 
between the different sites.

When it comes to using emacs with clearcase we do not use this
functionality but
I have seen that at least emacs 20.3 has support for this facility.

//Chris
-- 
============================================================================
Christopher Williams            Phone:    +353 902 31365 
Ericsson Systems 		ECN:	  8301365
Expertise Limited,		Mob:	  +353 87 64 888 04
Athlone,                        Fax:      +353 902 31304
Co.Westmeath,		        http://www.eei.ericsson.se/~eeiaxm3
Ireland            		chris.williams@REDACTED
============================================================================
Sean Hinde wrote:
> 
> All,
> 
> I'm thinking of buying a clever build management tools such as Rational
> ClearCase.
> 
> Does anyone have much experience of using these tools in an Erlang
> development environment. i.e. nice integration with emacs, and integration
> with the OTP directory structure, but also with some powerful features like
> parallel builds and checkpoint builds etc?
> 
> Particularly I'd like to hear if anyone has had to do large customisations
> of these tools to make them fit.
> 
> Thanks very much,
> 
> Sean


From ppetru@REDACTED  Fri Apr 14 11:52:27 2000
From: ppetru@REDACTED (Petru Paler)
Date: Fri, 14 Apr 2000 12:52:27 +0300
Subject: ClearCase and such like
In-Reply-To: <87itxlwch6.fsf@ghidra.vail>; from hal@vailsys.com on Thu, Apr 13, 2000 at 11:08:53PM -0500
References: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk> <87itxlwch6.fsf@ghidra.vail>
Message-ID: <20000414125227.A2370@coltronix.com>

On Thu, Apr 13, 2000 at 11:08:53PM -0500, Hal Snyder wrote:
> At one point at a site where they used ClearCase we had two
> contractors on site full time from Rational and got involved over
> several days in lengthy and increasingly existential discussions about
> the feasibility of distributed repositories over WAN connections.
> Something the free software guys do every day on a shoestring without
> even thinking about it.

    BitKeeper (http://www.bitkeeper.com) is also a very good choice.

-Petru


From etxuwig@REDACTED  Fri Apr 14 17:39:08 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Fri, 14 Apr 2000 17:39:08 +0200 (MET DST)
Subject: efficient line handling
Message-ID: <Pine.GSO.4.10.10004141436260.8311-100000@avc303>


Since the traffic in this forum is not exceptionally high, I thought
I'd pitch for my latest contrib: lines-1.1.

This is one of those toy problems that I find oddly relaxing.

I've given some thought off and on to how one would represent lines of
text in Erlang, e.g. when implementing a text editor. Obviously a
simple list would be pretty inefficient...

So, I implemented a module called lines.erl, which mimics a
dynamic array, in which you can easily insert and delete lines
anywhere, and maintain a sequential ordering. Access times are close
to those of ordered set tables. The implementation is a crudely
balanced B-tree, where each node contains a list of elements
(length(List) =< 10.) 

I thought performance was quite good when I tested it with 100,000
lines (mean: 30 usec (append), 16 usec (nth)).

Conceptually, the API works like the following implementation
(using a list):

append(Line, Lines) -> 
   Lines ++ [Line].

nth(Pos, Lines) ->
   lists:nth(Pos, Lines).

count(Lines) ->
   length(Lines).

insert(1, Lines, Line) ->
    [Line|Lines];
insert(N, [H|T], Line) when N > 1 ->
    [H|insert(N-1, T, Line)].

replace(1, [H|T], X) ->
   [X|T];
replace(N, [H|T], X) when N > 0 ->
   [H|replace(N-1, T, X)].

delete(1, [H|T]) ->
   T;
delete(N, [H|T]) when N > 0 ->
   [H|delete(N-1, T)].

When comparing my implementation with the above (naiive) one,
my Btree version beats the list version on 
- nth/2 on a 20-line structure
- delete/2 on a 20-line structure
- append/2 on a 300-line structure

(which makes sense, since ++ is a BIF.)

On 1,000 lines, the Btree version is:
- 20x faster on nth/2
- 25x faster on delete/2
- 4x faster on append/2
- well... 30x slower on insert(1,...)

Obviously, lines.erl could be used for something other than lines
of text... can't think of anything right now, though -- except
perhaps that a more sophisticated word processor might handle
paragraphs and page objects rather than lines of text.

So, now, anyone who wants to write an emacs clone in Erlang, will
at least have a reasonably efficient data structure for line
handling. (:

/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44








From tobbe@REDACTED  Fri Apr 14 18:12:37 2000
From: tobbe@REDACTED (Torbjorn Tornkvist)
Date: 14 Apr 2000 18:12:37 +0200
Subject: efficient line handling
In-Reply-To: Ulf Wiger's message of "Fri, 14 Apr 2000 17:39:08 +0200 (MET DST)"
References: <Pine.GSO.4.10.10004141436260.8311-100000@avc303>
Message-ID: <lopurs3bm2.fsf@kiwi.bluetail.com>


Great fun ! 

Then perhaps you could compare the performance with:

 http://www.bluetail.com/~tobbe/edit_buf.erl
                                edit_buf.hrl
                                edit.hrl

This is the core buffer handling of an Curses
based editor I started to write once.

/Tobbe


From Matthias.Lang@REDACTED  Sat Apr 15 10:01:39 2000
From: Matthias.Lang@REDACTED (Matthias.Lang@REDACTED)
Date: Sat, 15 Apr 2000 10:01:39 +0200 (MET DST)
Subject: ClearCase and such like
In-Reply-To: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk>
References: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk>
Message-ID: <14584.8675.4782.867790@gargle.gargle.HOWL>


 > I'm thinking of buying a clever build management tools such as Rational
 > ClearCase.
 > 
 > Does anyone have much experience of using these tools in an Erlang
 > development environment. i.e. nice integration with emacs, and integration

I worked a year in an Erlang project with about a dozen developers
where we used clearcase, I've also worked in a larger C++ project
which used clearcase. The feeling I got was the clearcase really
helped with the C++ project, while for Erlang it was occasionally
neat, but not worth the overhead---someone needs to maintain it,
someone needs to teach developers how it works, it's much more complex
than CVS. The things that impressed me in the C++ project were
  
   - wink-in (clearcase figures out that you're building the same
     binary someone else has built, and therefore you don't need
     to compile it again, clearcase "winks" it in from the other
     person's part of the filesystem) actually does save you time
     and disk space.

   - multisite. As long as "someone else" takes care of babysitting
     clearcase, the developers feel little pain when a project
     gets split across multiple sites, e.g. half the developers in
     Australia and the other half in Germany.

   - you have lots of information available about the past, e.g.
     when you're trying to figure out exactly why the wrong file
     got shipped to the customer, you can easily roll back the clock
     and go see what build commands were used to make that file.
     It's also possible to generate reports your semi-insane
     quality manager demands---e.g. he turns up and wants a report
     showing all binaries affected by a change in source file X
     made in the delivery 3 weeks ago. With CVS you can get that
     information by staring at Makefiles, re-running the build and
     taking an educated guess. Clearcase stores this information 
     automatically in its database.

   - you have power. If you think, say,  Dave is an idiot, it's
     easy to get the system to warn you whenever Dave makes a 
     change to your files. If you're heading towards a release, it's
     easy to lock the database so that only a couple of people
     have the power to make changes.

In a smaller project using Erlang, these featuers aren't all that
useful. Some of them are partially taken over by Erlang (e.g. a
bit of build information is stored in the .beam file), some are
mostly irrelevant to Erlang (wink-ins aren't imporant in Erlang
because compiling is relatively fast and it's rare to have to
recompile heaps of code because someone changed a .h file somewhere,
there typically aren't a lot of dependencies). 

Hope that helps.

Matt


From davidg@REDACTED  Sun Apr 16 03:49:55 2000
From: davidg@REDACTED (David Gould)
Date: Sat, 15 Apr 2000 18:49:55 -0700
Subject: ClearCase and such like
In-Reply-To: <87itxlwch6.fsf@ghidra.vail>; from Hal Snyder on Thu, Apr 13, 2000 at 11:08:53PM -0500
References: <402DD461F109D411977E0008C791C312564D79@imp02mbx.one2one.co.uk> <87itxlwch6.fsf@ghidra.vail>
Message-ID: <20000415184955.A11054@dnai.com>

On Thu, Apr 13, 2000 at 11:08:53PM -0500, Hal Snyder wrote:
> Sean Hinde <Sean.Hinde@REDACTED> writes:
> 
> > I'm thinking of buying a clever build management tools such as
> > Rational ClearCase.
> > 
> > Does anyone have much experience of using these tools in an Erlang
> > development environment. i.e. nice integration with emacs, and
> > integration with the OTP directory structure, but also with some
> > powerful features like parallel builds and checkpoint builds etc?
> > 
> > Particularly I'd like to hear if anyone has had to do large
> > customisations of these tools to make them fit.
> > 
> > Thanks very much,
> > 
> > Sean
> 
> I remember reading that Ericsson uses ClearCase for in-house version
> control. I have worked at installations using ClearCase and others
> using DSEE (ancestor of ClearCase), CVS, etc. I'd rather flip burgers
> than deal with ClearCase on a daily basis again; to me it seemed a
> slow, bloated, overpriced resource hog and an administrative
> sinkhole.

Hear Hear!

I have used clearcase in large environments for the last several years. I
would never again take a job at a place that used clearcase. To understate
the issue completely, it sucks. Rational sell a very nice fantasy of easy
management, "just see the files you need" etc, but in real life, you end up
with fantastically complex configspec files, vob corruption, winkins that
mysteriously do or do not happen when you want, product builds that contain
phantom winkins from long dead versions, multisite replication
missynchronization.

I could live with all that, but it also means that the CM system is now also
the file server. Each file open, each block read or write, each stat involves
multiple user space processes on multiple nodes doing database queries and
as a result the performance is completely horrible. At my last job if you
changed a top level header file (in C) you were done for the day, just go
home. It would take over six hours to build again. Without clearcase, the same
product would build from the top in less than 40 minutes.

The impact is to change the development experience from brisk focused
joyful work to a leaden soggy slog, every day another day in Siberian labor
camp.

If you are interested, send me mail and I will try to go into detail
about how I really feel ;-)

(Oh yeah, have a look at Perforce (www.perforce.com). I have tried their demo
and it rocks. Looks like it might do most of what clearcase claims as far
as easy branching too).

Or learn how to use CVS, it can do this job.

-dg

-- 
David Gould                davidg@REDACTED              510.536.1443 
- If simplicity worked, the world would be overrun with insects. -



From Sean.Hinde@REDACTED  Mon Apr 17 10:30:56 2000
From: Sean.Hinde@REDACTED (Sean Hinde)
Date: Mon, 17 Apr 2000 09:30:56 +0100
Subject: ClearCase and such like
Message-ID: <402DD461F109D411977E0008C791C312564D81@imp02mbx.one2one.co.uk>

Guys,

>Rational sell a very nice fantasy of easy
>management, "just see the files you need" 
>etc, but in real life, you end up
>with fantastically complex configspec files,

I've read the manual for it and I came to the same conclusion re the view
files etc.

Thanks for all your very interesting comments. I guess this is getting a bit
off subject now though.. Anyone know a good place where all this stuff is
natively discussed?

Thanks again,

Sean



From dne@REDACTED  Tue Apr 18 01:18:33 2000
From: dne@REDACTED (Daniel Neri)
Date: Tue, 18 Apr 2000 01:18:33 +0200
Subject: ClearCase and such like
In-Reply-To: Sean Hinde's message of "Mon, 17 Apr 2000 09:30:56 +0100"
References: <402DD461F109D411977E0008C791C312564D81@imp02mbx.one2one.co.uk>
Message-ID: <87puros4dy.fsf@nowhere.mayonnaise.net>

Sean Hinde <Sean.Hinde@REDACTED> writes:

> Anyone know a good place where all this stuff is natively discussed?

news:comp.software.config-mgmt maybe?


Regards,
/Daniel

-- 
Daniel Neri
dne@REDACTED


From geoff@REDACTED  Tue Apr 18 05:46:16 2000
From: geoff@REDACTED (Geoff Wong)
Date: Tue, 18 Apr 2000 13:46:16 +1000 (EST)
Subject: inet_gethost_native.
Message-ID: <200004180346.DAA14079@gecko.serc.rmit.edu.au>


Hi,

inet_gethost_native.erl (kernel lib)  has an interesting dependency 
upon being able to resolve names. If it fails a number of times
the kernel supervisor gets shutdown and the entire node goes down.
Since we're supposed to be building robust system this
isn't really good behaviour (the failure occurs sometime
after a cable is pulled on the box with the node in question).

My question is: is this the intended behaviour?

We've have a small patch that gives "better" behaviour
(in our opinion). Basically it shuts down the process
and its restart normally next time a resolution request is made
(so you can poll name resolution if you're waiting for a paritioned
network to come up again).

Can people see any problems with this patch (system affecting ones)?
And any reasons why this behaviour is "worse" than the current
behaviour?

Any feedback appreciated :)

Geoff

------ cut here


--- inet_gethost_native.erl	Tue Apr 18 11:58:34 2000
+++ inet_gethost_native.erl.orig	Tue Apr 18 11:58:33 2000
@@ -137,7 +137,7 @@
 		    {stop, Reason, {error, Reason}, State}
 		after Timeout ->
 			catch erlang:port_close(Port),
-			{stop, normal, {error, timeout}, State}
+			{stop, shutdown, {error, timeout}, State}
 	    end
     end.
 
@@ -212,7 +212,7 @@
 ensure_started() ->
     case whereis(inet_gethost_native) of
 	undefined -> 
-	    C = {inet_gethost_native, {?MODULE, start_link, []}, temporary, 1000, 
+	    C = {inet_gethost_native, {?MODULE, start_link, []}, permanent, 1000, 
 		 worker, [?MODULE]},
 	    case whereis(kernel_safe_sup) of
 		undefined ->



From hal@REDACTED  Tue Apr 18 08:35:00 2000
From: hal@REDACTED (Hal Snyder)
Date: 18 Apr 2000 01:35:00 -0500
Subject: erlang initial experiences
Message-ID: <87k8hv3oiz.fsf@ghidra.vail>

I've posted my first two Erlang programs at
  ftp://ftp.enteract.com/users/hal/erlang/fibsrch.erl
and
  ftp://ftp.enteract.com/users/hal/erlang/odd.erl

The latter prints how many 1's there are in the binary expansion of a
positive integer; the former does Fibonacci search for maximum of a
function on a finite interval. They were done with the otp_src_R6B-0
release running on a pre-release snapshot of OpenBSD-2.7.

I'd be interested in knowing how to improve them and in following
current Erlang usage as closely as possible.

My impressions while writing them:

1. Building OTP aborted on every directory with .java files. This was
due to the Makefiles trying to make .classes one at a time when there
were complex and sometimes circular dependencies. With both kjc-1.4C
on OpenBSD and Sun's native Java compiler (when I copied files to a
SparcStation for testing), it was necessary to feed all .java files at
once in a single command line to javac. With this workaround the build
completed successfully.

2. I see there's a bsr but no logical shift right. A minor annoyance.

3. Support for parsing of command line arguments passed from the UNIX
shell seems limited. No getopt() (or did I miss it?), and numbers
are passed in as atoms so must go through the dual conversion of
atom_to_list and list_to_integer.

4. The second program has perfectly legal balanced exports of
variables from both branches of an if structure. This leads to a slew
of inappropriate warnings - and I don't see any way to turn them off
without rebuilding the compiler. There is a compiler switch to enable
warning reports, on by default, but no apparent way to turn it off.

Am I off base on any of these items? Erlang is fun, but there seem to
be some rough edges. I plan to stay with it at least long enough to
write more than toy programs.



From Pekka.Hedqvist@REDACTED  Wed Apr 19 04:25:36 2000
From: Pekka.Hedqvist@REDACTED (Pekka.Hedqvist@REDACTED)
Date: Wed, 19 Apr 2000 12:25:36 +1000 (EST)
Subject: erl 4.9.1. gen_udp, udp packages 
Message-ID: <14589.6432.898669.341619@eddieware.eddieware.org>

When you receive udp packages they look something like:
{udp,{socket,<0.41.0>,#Port<0.12>,inet_udp},
     {203,102,230,172},
     1024,
     [1,2,3,4,5,6,7]}

I suppose the "1024" means something, I asumed its the port number but
its not, its always 1024 and increasing with the number of open ports
so what does it represent?


From Pekka.Hedqvist@REDACTED  Wed Apr 19 06:30:58 2000
From: Pekka.Hedqvist@REDACTED (Pekka.Hedqvist@REDACTED)
Date: Wed, 19 Apr 2000 14:30:58 +1000 (EST)
Subject: erlang:now() in erlang 4.9.1 on Linux
Message-ID: <14589.13954.505029.822433@eddieware.eddieware.org>


When trying to measure time we get really weird values from the
'erlang:now()' when two successive calls to it are done with less than
100 microseconds between the two calls. The values are far too low; 0,
1 microseconds are reported even when maybe 60-80 has passed. If the
calls are made further apart timewise they suddenly jump up to
reasonable represent the passed time (when > ~100 micro has passed).

For example, calling gettimeofday() in Linux directly every ~7 
microseconds also returns ~7 micro each time. 

Looking at the erl_time_sup.c one sees that it builds without
gethrtime() (since its not available in plain Linux) and with the
'CORRECT_USING_TIMES' defined. 'erlang:now()' results in a call to
get_tolerant_timeofday(void) which does a number of things, some
regarding internal erlang timing etc.

I asume (hopefully) that the get_tolerant_timeofday(void) does the
right things regarding Erlangs internal view of time, but is its
side-effect on functions like erlang:now() really desirable?  
If so, how is one to measure time in a way that avoids these "jumps"?  
Write a linked in driver calling gettimeofday() directly etc..?

Ideas, oppinions?

/pekka


From jon@REDACTED  Wed Apr 19 07:05:51 2000
From: jon@REDACTED (Jon Holdsworth)
Date: Wed, 19 Apr 2000 15:05:51 +1000
Subject: erl 4.9.1. gen_udp, udp packages
References: <14589.6432.898669.341619@eddieware.eddieware.org>
Message-ID: <38FD3EAF.C0F00451@eddieware.org>

Highest Priveliged port so far ?

Jon


Pekka.Hedqvist@REDACTED wrote:

> When you receive udp packages they look something like:
> {udp,{socket,<0.41.0>,#Port<0.12>,inet_udp},
>      {203,102,230,172},
>      1024,
>      [1,2,3,4,5,6,7]}
>
> I suppose the "1024" means something, I asumed its the port number but
> its not, its always 1024 and increasing with the number of open ports
> so what does it represent?



From not.for.email@REDACTED  Wed Apr 19 09:01:08 2000
From: not.for.email@REDACTED (Gordon Beaton)
Date: 19 Apr 2000 07:01:08 GMT
Subject: erlang initial experiences
References: <87k8hv3oiz.fsf@ghidra.vail>
Message-ID: <8djljk$1q3$1@news.du.uab.ericsson.se>

On 18 Apr 2000 06:35:00 GMT, Hal Snyder wrote:
> 1. Building OTP aborted on every directory with .java files. This was
> due to the Makefiles trying to make .classes one at a time

You're completely right - the OTP way of building java really sucks.

Part of the problem, I guess, is due to the fact that javac and
clearmake aren't on particularly friendly terms. Another is that java
was introduced into OTP relatively late in the game and nobody sat
down to try to figure out the best way to integrate the java
components into the build system properly, resulting in a few
inconsistencies in that area.

For references and opinions, see the recent thread about clearcase...

/gordon

-- 
g o r d o n . b e a t o n @ e r i c s s o n . c o m


From per@REDACTED  Wed Apr 19 11:22:29 2000
From: per@REDACTED (Per Hedeland)
Date: Wed, 19 Apr 2000 11:22:29 +0200 (MET DST)
Subject: erl 4.9.1. gen_udp, udp packages
In-Reply-To: <14589.6432.898669.341619@eddieware.eddieware.org>
References: <14589.6432.898669.341619@eddieware.eddieware.org>
Message-ID: <200004190922.LAA03714@aalborg.du.uab.ericsson.se>

Pekka.Hedqvist@REDACTED wrote:
>When you receive udp packages they look something like:
>{udp,{socket,<0.41.0>,#Port<0.12>,inet_udp},
>     {203,102,230,172},
>     1024,
>     [1,2,3,4,5,6,7]}
>
>I suppose the "1024" means something, I asumed its the port number but
>its not, its always 1024 and increasing with the number of open ports
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>so what does it represent?         ^^ Huh?:-)

The man page seems clear, and not obviously contradicting what you're
seeing:

              When UDP packets arrive at  the  opened  Port  they
              will  be  delivered  as  messages of the type {udp,
              Socket, IP, InPortNo, Packet}

              IP and  InPortNo  define  the  address  from  which
              Packet  came.

I.e. the number is the *source* port of the packet - delivering the
destination port with each packet isn't obviously useful.:-) If the
sender didn't bind to a specific port (in Erlang: Passed a Port value of
0 to gen_udp:open()), the kernel / IP stack will allocate one - the
algorithm for this varies, but on many/most Unices it will be the first
"free" port above 1023.

--Per Hedeland
per@REDACTED



From etxuwig@REDACTED  Wed Apr 19 11:43:35 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Wed, 19 Apr 2000 11:43:35 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <14589.13954.505029.822433@eddieware.eddieware.org>
Message-ID: <Pine.GSO.4.10.10004190924030.12777-100000@avc303>


I don't know if this answers your questions, but it may provide some
background to erlang:now() issues.

At AXD 301, we've had some problems with the internal time
representation, as we've run some pretty abusive tests on the network
time synchronization mechanisms. We voiced the requirement that the
real-time clock must operate reliably regardless of the system time.

The specific problem is when you do stuff like "rdate" on a running
system, or someone manually alters the system clock. In previous
versions of Erlang/OTP, this was disastrous for the system, since
timeouts, and erlang:now(), were based on the system clock.
For example, if the system time was set back a couple of hours,
timeout activity in Erlang would basically stop until the system
clock "caught up" with the Erlang clock. This would throw our system
into some kind of undefined state.

In our current, patched version of OTP R5B01, we have a VM modified to
decouple the internal Erlang clock from the system clock, and then
checkpoint the two every once in a while. Should the clocks drift
apart, the internal Erlang clock will adjust itself (=< +-1%) to
slowly synchronize with the system clock.



/Uffe

On Wed, 19 Apr 2000 Pekka.Hedqvist@REDACTED wrote:

>
>When trying to measure time we get really weird values from the
>'erlang:now()' when two successive calls to it are done with less than
>100 microseconds between the two calls. The values are far too low; 0,
>1 microseconds are reported even when maybe 60-80 has passed. If the
>calls are made further apart timewise they suddenly jump up to
>reasonable represent the passed time (when > ~100 micro has passed).
>
>For example, calling gettimeofday() in Linux directly every ~7 
>microseconds also returns ~7 micro each time. 
>
>Looking at the erl_time_sup.c one sees that it builds without
>gethrtime() (since its not available in plain Linux) and with the
>'CORRECT_USING_TIMES' defined. 'erlang:now()' results in a call to
>get_tolerant_timeofday(void) which does a number of things, some
>regarding internal erlang timing etc.
>
>I asume (hopefully) that the get_tolerant_timeofday(void) does the
>right things regarding Erlangs internal view of time, but is its
>side-effect on functions like erlang:now() really desirable?  
>If so, how is one to measure time in a way that avoids these "jumps"?  
>Write a linked in driver calling gettimeofday() directly etc..?
>
>Ideas, oppinions?
>
>/pekka
>

-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44






From etxuwig@REDACTED  Wed Apr 19 11:46:09 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Wed, 19 Apr 2000 11:46:09 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <Pine.GSO.4.10.10004190924030.12777-100000@avc303>
Message-ID: <Pine.GSO.4.10.10004191144250.12777-100000@avc303>


Sorry, I meant to cancel this post, but my fingers tricked me.
I've read erl_time_sup.c and have nothing really intelligent to
contribute at the moment.

/Uffe


On Wed, 19 Apr 2000, Ulf Wiger wrote:

>
>I don't know if this answers your questions, but it may provide some
>background to erlang:now() issues.
>
>At AXD 301, we've had some problems with the internal time
>representation, as we've run some pretty abusive tests on the network
>time synchronization mechanisms. We voiced the requirement that the
>real-time clock must operate reliably regardless of the system time.
>
>The specific problem is when you do stuff like "rdate" on a running
>system, or someone manually alters the system clock. In previous
>versions of Erlang/OTP, this was disastrous for the system, since
>timeouts, and erlang:now(), were based on the system clock.
>For example, if the system time was set back a couple of hours,
>timeout activity in Erlang would basically stop until the system
>clock "caught up" with the Erlang clock. This would throw our system
>into some kind of undefined state.
>
>In our current, patched version of OTP R5B01, we have a VM modified to
>decouple the internal Erlang clock from the system clock, and then
>checkpoint the two every once in a while. Should the clocks drift
>apart, the internal Erlang clock will adjust itself (=< +-1%) to
>slowly synchronize with the system clock.
>
>
>
>/Uffe
>
>On Wed, 19 Apr 2000 Pekka.Hedqvist@REDACTED wrote:
>
>>
>>When trying to measure time we get really weird values from the
>>'erlang:now()' when two successive calls to it are done with less than
>>100 microseconds between the two calls. The values are far too low; 0,
>>1 microseconds are reported even when maybe 60-80 has passed. If the
>>calls are made further apart timewise they suddenly jump up to
>>reasonable represent the passed time (when > ~100 micro has passed).
>>
>>For example, calling gettimeofday() in Linux directly every ~7 
>>microseconds also returns ~7 micro each time. 
>>
>>Looking at the erl_time_sup.c one sees that it builds without
>>gethrtime() (since its not available in plain Linux) and with the
>>'CORRECT_USING_TIMES' defined. 'erlang:now()' results in a call to
>>get_tolerant_timeofday(void) which does a number of things, some
>>regarding internal erlang timing etc.
>>
>>I asume (hopefully) that the get_tolerant_timeofday(void) does the
>>right things regarding Erlangs internal view of time, but is its
>>side-effect on functions like erlang:now() really desirable?  
>>If so, how is one to measure time in a way that avoids these "jumps"?  
>>Write a linked in driver calling gettimeofday() directly etc..?
>>
>>Ideas, oppinions?
>>
>>/pekka
>>
>
>

-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44



From Matthias.Lang@REDACTED  Wed Apr 19 14:15:57 2000
From: Matthias.Lang@REDACTED (Matthias.Lang@REDACTED)
Date: Wed, 19 Apr 2000 14:15:57 +0200 (MET DST)
Subject: disabling compiler warnings
Message-ID: <14589.41853.114093.347788@gargle.gargle.HOWL>

Hi,

Hal Snyder writes

    Hal> 4. The second program has perfectly legal balanced exports of
    Hal> variables from both branches of an if structure. This leads
    Hal> to a slew of inappropriate warnings - and I don't see any way
    Hal> to turn them off without rebuilding the compiler. There is a
    Hal> compiler switch to enable warning reports, on by default, but
    Hal> no apparent way to turn it off.

I agree that the warnings in the fibsrch program (the first one)
are rather over-zealous of the compiler, but there are slightly more
verbose ways to code around the warnings, which save your bacon in
other cases.

In any case, disabling the warnings doesn't require a rebuild. Just
create a user_default.beam from source something like:

	-module(user_default).
	-export([c/1]).
	c(File) -> compile:file(File, []).

You can arrange for this to be loaded automatically via the .erlang file:

        code:load_abs("/home/super/mml/toys/user_default").

Read more about the .erlang and user_default file at

        http://www.erlang.org/documentation/doc/getting_started/getting_started.html#1.7

Matt


From gunilla@REDACTED  Wed Apr 19 14:34:22 2000
From: gunilla@REDACTED (Gunilla Hugosson)
Date: Wed, 19 Apr 2000 14:34:22 +0200
Subject: disabling compiler warnings
References: <14589.41853.114093.347788@gargle.gargle.HOWL>
Message-ID: <38FDA7CE.ECB92282@erix.ericsson.se>

Based on my experiences from teaching Erlang courses,
the warnings really are useful. A more experienced
programmer can turn off the warnings like Mattias indicated.

In my mind, an even better solution to the problem is to
rewrite the if.  Instead of:

 if
   Bertil>3 ->
     Arne = true;
   true ->
     Arne = false
 end

Write:
  Arne = if
           Bertil>3 ->
             true;
           true ->
             false
         end

/ Gunilla

Matthias.Lang@REDACTED wrote:
> 
> Hi,
> 
> Hal Snyder writes
> 
>     Hal> 4. The second program has perfectly legal balanced exports of
>     Hal> variables from both branches of an if structure. This leads
>     Hal> to a slew of inappropriate warnings - and I don't see any way
>     Hal> to turn them off without rebuilding the compiler. There is a
>     Hal> compiler switch to enable warning reports, on by default, but
>     Hal> no apparent way to turn it off.
> 
> I agree that the warnings in the fibsrch program (the first one)
> are rather over-zealous of the compiler, but there are slightly more
> verbose ways to code around the warnings, which save your bacon in
> other cases.
> 
> In any case, disabling the warnings doesn't require a rebuild. Just
> create a user_default.beam from source something like:
> 
>         -module(user_default).
>         -export([c/1]).
>         c(File) -> compile:file(File, []).
> 
> You can arrange for this to be loaded automatically via the .erlang file:
> 
>         code:load_abs("/home/super/mml/toys/user_default").
> 
> Read more about the .erlang and user_default file at
> 
>         http://www.erlang.org/documentation/doc/getting_started/getting_started.html#1.7
> 
> Matt


From thomas@REDACTED  Wed Apr 19 15:37:40 2000
From: thomas@REDACTED (Thomas Arts)
Date: Wed, 19 Apr 2000 15:37:40 +0200
Subject: disabling compiler warnings
References: <14589.41853.114093.347788@gargle.gargle.HOWL> <38FDA7CE.ECB92282@erix.ericsson.se>
Message-ID: <38FDB6A4.FFDB8EEB@cslab.ericsson.se>

Gunilla Hugosson wrote:
> 
> Based on my experiences from teaching Erlang courses,
> the warnings really are useful. A more experienced
> programmer can turn off the warnings like Mattias indicated.
> 
> In my mind, an even better solution to the problem is to
> rewrite the if.  Instead of:
> 
>  if
>    Bertil>3 ->
>      Arne = true;
>    true ->
>      Arne = false
>  end
> 
> Write:
>   Arne = if
>            Bertil>3 ->
>              true;
>            true ->
>              false
>          end

Or use logic and write:

Arne = Bertil =< 3.

/Thomas

Rule of thumb: if you see a line "false -> true" you missed an opertunity to shrink
the codesize.


From thomas@REDACTED  Wed Apr 19 15:41:10 2000
From: thomas@REDACTED (Thomas Arts)
Date: Wed, 19 Apr 2000 15:41:10 +0200
Subject: disabling compiler warnings
References: <14589.41853.114093.347788@gargle.gargle.HOWL> <38FDA7CE.ECB92282@erix.ericsson.se> <38FDB6A4.FFDB8EEB@cslab.ericsson.se>
Message-ID: <38FDB776.1F814395@cslab.ericsson.se>

Thomas Arts wrote:
> 
> Gunilla Hugosson wrote:
> >
> > Based on my experiences from teaching Erlang courses,
> > the warnings really are useful. A more experienced
> > programmer can turn off the warnings like Mattias indicated.
> >
> > In my mind, an even better solution to the problem is to
> > rewrite the if.  Instead of:
> >
> >  if
> >    Bertil>3 ->
> >      Arne = true;
> >    true ->
> >      Arne = false
> >  end
> >
> > Write:
> >   Arne = if
> >            Bertil>3 ->
> >              true;
> >            true ->
> >              false
> >          end
> 
> Or use logic and write:
> 
> Arne = Bertil =< 3.

Uh, sorry, for those that read these: Arne = Bertil > 3.

/Thomas


From Sean.Hinde@REDACTED  Wed Apr 19 15:51:21 2000
From: Sean.Hinde@REDACTED (Sean Hinde)
Date: Wed, 19 Apr 2000 14:51:21 +0100
Subject: erl 4.9.1. gen_udp, udp packages
Message-ID: <402DD461F109D411977E0008C791C312564D9A@imp02mbx.one2one.co.uk>

> I.e. the number is the *source* port of the packet - delivering the
> destination port with each packet isn't obviously useful.:-) If the
> sender didn't bind to a specific port (in Erlang: Passed a 
> Port value of

And not only that, If you want to send a reply to the application which
originated the udp packet, it is this port you need to use rather than the
one you opened it with. (I hit this one with my RADIUS implementation!)

Rgds,

Sean


From crd@REDACTED  Wed Apr 19 16:09:26 2000
From: crd@REDACTED (Craig Dickson)
Date: Wed, 19 Apr 2000 07:09:26 -0700
Subject: disabling compiler warnings
References: <14589.41853.114093.347788@gargle.gargle.HOWL>
Message-ID: <001c01bfaa08$fdb633e0$6f01140a@inkpad>

Matthias Lang wrote:

> You can arrange for this to be loaded automatically via the .erlang file:

Okay, but according to the documentation you referenced, the .erlang file
can be loaded from the user's home directory. What is considered to be the
"user's home directory" on MS Windows? I have a HOME environment variable
defined (used by Emacs, among other things), but Erlang seems to ignore it.

Craig




From mskow@REDACTED  Wed Apr 19 19:46:10 2000
From: mskow@REDACTED (Michael Skowronski)
Date: Wed, 19 Apr 2000 13:46:10 -0400 (EDT)
Subject: orber
Message-ID: <Pine.LNX.4.20.0004191340540.2033-100000@poseidon.crosslink.net>

Hello,

does anyone have a simple example of how to connect a java visibroker
client to an orber service?

thanks.

Michael




From per@REDACTED  Thu Apr 20 00:27:09 2000
From: per@REDACTED (Per Hedeland)
Date: Thu, 20 Apr 2000 00:27:09 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <14589.13954.505029.822433@eddieware.eddieware.org>
References: <14589.13954.505029.822433@eddieware.eddieware.org>
Message-ID: <200004192227.e3JMR9I08267@super.du.uab.ericsson.se>

Pekka.Hedqvist@REDACTED wrote:
>When trying to measure time we get really weird values from the
>'erlang:now()' when two successive calls to it are done with less than
>100 microseconds between the two calls. The values are far too low; 0,
>1 microseconds are reported even when maybe 60-80 has passed. If the
>calls are made further apart timewise they suddenly jump up to
>reasonable represent the passed time (when > ~100 micro has passed).

Do you really ever see a difference of 0 microseconds? That would be a
serious bug, monotonically increasing values is just about the only
thing erlang:now() *really* promises to produce. I can't reproduce
*that* even by calling it several thousand times in a tight loop (on
RedHat 6.1).

I do however see jumps along the lines of what you describe,
specifically when doing the above tight-loop calls it increases by 1
microsecond on each call for several hundred calls, then makes a jump of
8000-9000 microseconds, then 40-50 "reasonable" increments, and then
back to 1 microsecond increments again.

>Looking at the erl_time_sup.c one sees that it builds without
>gethrtime() (since its not available in plain Linux) and with the
>'CORRECT_USING_TIMES' defined. 'erlang:now()' results in a call to
>get_tolerant_timeofday(void) which does a number of things, some
>regarding internal erlang timing etc.
>
>I asume (hopefully) that the get_tolerant_timeofday(void) does the
>right things regarding Erlangs internal view of time, but is its
>side-effect on functions like erlang:now() really desirable?  

Well, it has to affect erlang:now() (see Ulf's message for why these
corrections are done at all), but it shouldn't have *this* effect - in
fact unless you keep changing the system time, it shouldn't have any
effect at all. It seems clear that the reason is that the 10-ms
resolution of times() is incorrectly affecting the results, and indeed
it goes away if you recompile without CORRECT_USING_TIMES defined - so
doing that is at least a workaround for now (at least for the problem
I'm seeing). 

Incidentally, Linux is currently the only OS that CORRECT_USING_TIMES
gets defined on - I don't know how many besides Solaris that have
gethrtime().

--Per Hedeland
per@REDACTED


From luke@REDACTED  Thu Apr 20 10:35:44 2000
From: luke@REDACTED (Luke Gorrie)
Date: 20 Apr 2000 10:35:44 +0200
Subject: orber
In-Reply-To: Michael Skowronski's message of "Wed, 19 Apr 2000 13:46:10 -0400 (EDT)"
References: <Pine.LNX.4.20.0004191340540.2033-100000@poseidon.crosslink.net>
Message-ID: <874s8xqie7.fsf@cockatoo.bluetail.com>

Michael Skowronski <mskow@REDACTED> writes:

> Hello,
> 
> does anyone have a simple example of how to connect a java visibroker
> client to an orber service?

I have, though I used JacORB rather than
Visibroker. http://203.46.39.99:2000/get?node=orber+quickstart

Cheers,
Luke



From jhague@REDACTED  Thu Apr 20 03:30:37 2000
From: jhague@REDACTED (James Hague)
Date: Wed, 19 Apr 00 20:30:37 -0500
Subject: erlang initial experiences
Message-ID: <200004200129.UAA12017@node-03.advancenet.net>

>3. Support for parsing of command line arguments passed from the UNIX
>shell seems limited. No getopt() (or did I miss it?), and numbers
>are passed in as atoms so must go through the dual conversion of
>atom_to_list and list_to_integer.

Erlang hasn't been much of a Perl-like scripting language thus far, so 
I'm not suprised by this.  With the standalone application stuff getting 
better, I could see better command line parsing being more of an issue.


From scott@REDACTED  Thu Apr 20 06:10:05 2000
From: scott@REDACTED (Scott Lystig Fritchie)
Date: Wed, 19 Apr 2000 23:10:05 -0500
Subject: erlang initial experiences 
In-Reply-To: Message of "Wed, 19 Apr 2000 20:30:37 EST."
             <200004200129.UAA12017@node-03.advancenet.net> 
Message-ID: <200004200410.XAA55864@snookles.snookles.com>

>>>>> "jh" == James Hague <jhague@REDACTED> writes:

>> 3. Support for parsing of command line arguments passed from the
>> UNIX shell seems limited. No getopt() (or did I miss it?), and
>> numbers are passed in as atoms so must go through the dual
>> conversion of atom_to_list and list_to_integer.

jh> Erlang hasn't been much of a Perl-like scripting language thus
jh> far, so I'm not suprised by this.

See the documentation for the init module (in the kernel docs).
Here's a snippet to get an integer value off the command line,
returning 'false' if it isn't there:

        get_command_line_int(Atom) ->
            case init:get_argument(Atom) of
                {ok, [[Value]]} ->
                    list_to_integer(Value);
                _ ->
                    false
            end.

... where the command line argument looks like "-whatever 4", and
'whatever' is arg passed to get_command_line_int/1.

-Scott


From miyakawa@REDACTED  Thu Apr 20 04:31:27 2000
From: miyakawa@REDACTED (Shinya MIYAKAWA)
Date: Thu, 20 Apr 2000 11:31:27 +0900
Subject: IFIP TCS2000 INFORMATION
Message-ID: <20000420113127Q.miyakawa@ito.ecei.tohoku.ac.jp>

[Apologies for multiple copies]

IFIP TCS2000 PRELIMINARY PROGRAM AND REGISTRATION INFORMATION
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
--------------------------------------------------------------------------

IFIP International Conference on Theoretical Computer Science 
                   (IFIP TCS2000)
 --- Exploring New Frontiers of Theoretical Informatics ---

 August 17 - 19, 2000

 Aoba Memorial Bldg., Tohoku University, Sendai, Japan

 Further Information about IFIP TCS2000 can be obtained on the Web, at

       http://tcs2000.ito.ecei.tohoku.ac.jp/tcs2000/

 Any inquiry on IFIP TCS2000 Program and Registration may be directed to

       TCS2000@REDACTED

--------------------------------------------------------------------------

PRELIMINARY PROGRAM
^^^^^^^^^^^^^^^^^^^
  [Outline]
   
      AUGUST 16: 15:00 Registration at Sendai Tokyu Hotel till 20:00
                 18:00 Welcome at Sendai Tokyu Hotel till 19:00

      AUGUST 17:  9:30 Opening Session 
                 10:00 Keynote Plenary Talk 1
                 -----------------------------------------
                 11:10 - 17:30  TRACK (1)  ||  TRACK (2) 
                 -----------------------------------------

      AUGUST 18:  9:10 Keynote Plenary Talk 2 
                 -----------------------------------------
                 10:20 - 15:30  TRACK (1)  ||  TRACK (2)
                 -----------------------------------------
                 15:50 Panel Discussion till 17:10
                 -----------------------------------------
                 18:30 Banquet at Sendai Tokyu Hotel

      AUGUST 19:  9:10 Keynote Plenary Talk 3 
                 -----------------------------------------
                 10:20 - 14:20  TRACK (1)  ||  TRACK (2)
                 -----------------------------------------
                 14:30 Closing Session till 14:40
                 -----------------------------------------
                 15:00 Open Lectures till 17:00
                 -----------------------------------------
                 18:30 Japanese Dinner Party till 20:00
                 -----------------------------------------

AUGUST 16 WEDNESDAY
^^^^^^^^^^^^^^^^^^^
  15:00 REGISTRATION at Sendai Tokyu Hotel till 20:00

  18:00 WELCOME with light snack at Sendai Tokyu Hotel till 19:00

AUGUST 17 THURSDAY
^^^^^^^^^^^^^^^^^^
   9:30 OPENING SESSION
        Giorgio Ausiello (TC1 Chair and IFIP TCS2000 Co-Chair)
        Takayasu Ito (IFIP TCS2000 Co-Chair)
  
  10:00 KEYNOTE PLENARY TALK
        Reconciling Two Views of Cryptography
        Martin Abadi (Bell Labs, Lucent)

  10:50 Break

 [TRACK (1)]

            SESSION (1.1), 11:10 - 12:00

  11:10 Approximation Algorithms for String Folding Problems
        Giancarlo Mauri, Giulio Pavesi

  11:35 An Index for Two Dimensional String Matching Allowing Rotations
        Kimmo Fredriksson, Gonzalo Navarro, Esko Ukkonen

  12:00 Lunch Break

            SESSION (1.2),  13:30 - 14:20

  13:30 Parallel Edge Coloring of a Tree on a Mesh Connected Computer
        Chang-Sung Jeong, Sung-Up Cho, Mi-Young Choi

  13:55 Parallel Approximation Algorithms for Maximum Weighted Matching
        in General Graphs
        Ryuhei Uehara, Zhi-Zhong Chen

  14:20 Break

  14:40 TRACK (1) INVITED TALK
        It is on the Boundary: Complexity Considerations for Polynomial 
        Ideals
        Ernst Mayr (TU Muenchen)

  15:30 Break

            SESSION (1.3), 15:50 - 17:30

  15:50 An Efficient Parallel Algorithm for Scheduling Interval Ordered 
        Tasks
        Yoojin Chung, Kunsoo Park

  16:15 Task Distributions on Multiprocessor Systems
        Evgeny V. Shchepin, Nodari Vakhania

  16:40 Fast Interpolation using Kohonen Self-Organizing Neural Networks
        Olivier Sarzeaud, Yann Stephan

  17:05 Steganography Using Modern Arts
        Galdi Clemente, Blundo Carlo

  17:30 Break

  -----------//

 [TRACK (2)]

            SESSION (2.1), 11:10 - 12:00

  11:10 Ambient Groups and Mobility Types
        Luca Cardelli, Giorgio Ghelli, Andrew D. Gordon

  11:35 An Asynchronous, Distributed Implementation of Mobile Ambients
        Cedric Fournet, Jean-Jacques Levy, Alan Schmitt

  12:00 Lunch Break

  13:30 TRACK (2) INVITED TALK
        Type Systems for Concurrent Processes: From Deadlock-Freedom to 
        Livelock-Freedom, Time-Boundedness
        Naoki Kobayashi (U. Tokyo)

  14:20 Break

            SESSION (2.2), 14:40 - 15:30

  14:40 Local pi-Calculus at Work: Mobile Objects as Mobile Processes
        Massimo Merro, Josva Kleist, Uwe Nestmann

  15:05 An Interpretation of Typed Concurrent Objects in the Blue Calculus
        Silvano Dal-Zilio

  15:30 Break

            SESSION (2.3), 15:50 - 17:30

  15:50 A Higher-Order Specification of the pi-Calculus
        Joelle Despeyroux

  16:15 Open Ended Systems, Dynamic Bisimulation, and Tile Logic
        Vladimiro Sassone

  16:40 Fibred Models of Processes: Discrete, Continuous, and Hybrid Systems
        Marcelo Fiore

  17:05 On the Complexity of Bisimulation Problems for Pushdown Automata
        Richard Mayr

  17:30 Break

AUGUST 18 FRIDAY
^^^^^^^^^^^^^^^^
   9:10 KEYNOTE PLENARY TALK
        Theory and Construction of Molecular Computers
        Masami Hagiya (U. Tokyo)

  10:00 Break

 [TRACK (1)]

            SESSION (1.4), 10:20 - 12:00

  10:20 Trade-offs between Density and Robustness in Random Interconnection
        Graphs
        P. Flajolet, K. Hatzis, S. Nikoletseas, P. Spirakis

  10:45 The ($\sigma$+1)-Edge-Connectivity Augmentation Problem without 
        Creating Multiple Edges
        Satoshi Taoka, Toshimasa Watababe

  11:10 On the Hardness of Approximating Some NP-optimization Problems 
        Related to Minimum Linear Ordering Problem
        Sounaka Mishra, Kripasindhu Sikdar

  11:35 Maximum Clique and Minimum Clique Partition in Visibility Graphs
        Stephan Eidenbenz

  12:00 Lunch Break

            SESSION (1.5), 13:30 - 14:20

  13:30 Real-Time Language Recognition by Alternating Cellular Automata
        Thomas Buchholz, Andreas Klein, Martin Kutrib

  13:55 Damage Spreading and $\mu$-Sensitivity on CA
        Bruno Martin

  14:20 Break

  14:40 TRACK (1) INVITED TALK
        Discrepancy Theory and its Applications to Finance
        Shu Tezuka (IBM Tokyo Research Lab)

  15:30 Break

  -----------//

 [TRACK (2)]

            SESSION (2.4), 10:20 - 12:00

  10:20 A Type-theoretic Study on Partial Continuations
        Yukiyoshi Kameyama

  10:45 Partially Typed Terms between Church-Style and Curry-Style
        Ken-etsu Fujita, Aleksy Schubert

  11:10 Alternating Automata and Logics over Infinite Words
        Christof Loeding, Wolfgang Thomas

  11:35 Hypothesis Support for Information Integration in Four-Valued Logics
        Yann Loyer, Nicolas Spyratos, Daniel Stamate

  12:00 Lunch Break

  13:30 TRACK (2) INVITED TALK
        A Compositional Model of Time and Uncertainty
        Thomas Henzinger (UC Berkeley)

  14:20 Break

            SESSION (2.5), 14:40 - 15:30

  14:40 A Single Complete Refinement Rule for Demonic Specifications
        Karl Lermer, Paul Strooper

  15:05 Reasoning about Composition using Property Transformers and their 
        Conjugates
        Michel Charpentier, K. Mani Chandy
        
  15:30 Break

  -----------------------
 
  15:50 PANEL DISCUSSION on "New Challenges for TCS"
        Panelists: Giorgio Ausiello (U. Roma "La Sapienza")
                   Jozef Gruska <Co-Chair> (Masaryk U.)
                   Ugo Montanari (U. Pisa)
                   Takao Nishizeki <Co-Chair> (Tohoku U.)
                   Yoshihito Toyama (Tohoku U.)
                   Jiri Wiedermann (Inst. Informatics, Prague)

  17:10 Break

  18:30 BANQUET at Sendai Tokyu Hotel till 20:45
        BANQUET SPEECH
        Non-Random Thoughts about Randomization
        Michael O. Rabin (Harvard U.)

AUGUST 19 SATURDAY
^^^^^^^^^^^^^^^^^^
   9:10 KEYNOTE PLENARY TALK
        List Decoding: Algorithms and Applications
        Madhu Sudan (MIT)

  10:00 Break

 [TRACK (1)]

            SESSION (1.6), 10:20 - 12:00

  10:20 Fully Consistent Extensions of Partially Defined Boolean Functions
        with Missing Bits
        Endre Boros, Toshihide Ibaraki, Kazuhisa Makino

  10:45 Characterization of Optimal Key Set Protocols
        Takaaki Mizuki, Hiroki Shizuya, Takao Nishizeki

  11:10 On the Complexity of Integer Programming in the Blum-Shub-Smale
        Computational Model
        Valentin E. Brimkov, Stefan S. Dantchev

  11:35 On Logarithmic Simulated Annealing
        A. Albrecht, C.K. Wong

  12:00 Lunch Break

  13:30 TRACK (1) INVITED TALK
        Hierarchical State Machines
        Mihalis Yannakakis (Bell Labs, Lucent)

  14:20 Break

  -----------//

 [TRACK (2)]

  10:20 TRACK (2) INVITED TALK
        Some New Directions in the Syntax and Semantics of Formal Languages
        Gordon D. Plotkin (Edinburgh U.)

  11:10 Break

  11:20 DEMO SESSION (1) on Verification Tools

  12:00 Lunch Break

  13:30 DEMO SESSION (2) on Verification Tools

  14:20 Break

 ------------------------

  14:30 CLOSING SESSION till 14:40
        Giorgio Ausiello (TC1 Chair and IFIP TCS2000 Co-Chair) 
        Takayasu Ito (IFIP TCS2000 Co-Chair)

 ------------------------

 [OPEN LECTURES]

  15:00 On the Power of Interactive Computing
        Jan van Leeuwen (U. Utrecht)

  16:00 The Varieties of Programming Language Semantics
        Peter D. Mosses (U. Aarhus)

  17:00 Break

 ------------------------

  18:30 JAPANESE DINNER PARTY till 20:00

==========================================================================

GENERAL INFORMATION
^^^^^^^^^^^^^^^^^^^

IFIP TCS2000 is the first International Conference on Theoretical Computer 
Science organized by IFIP TC1 on Foundations of Computer Science, and it 
consists of two tracks: TRACK (1) on Algorithms, Complexity and Models of 
Computation, and TRACK (2) on Logic, Semantics, Specification, and 
Verification. The conference proceedings will be published as a volume
of Lecture Notes in Computer Science, Springer-Verlag.

IFIP TCS2000 will be held on the campus of Tohoku University, Sendai, Japan.
The invited talks and contributed talks will be presented at the Aoba 
Memorial Building and Engineering Conference Hall, Faculty of Engineering 
located on the Aoba Hill about 3 km west of downtown Sendai. The conference
welcome reception and banquet will be held at Sendai Tokyu Hotel, located 
at downtown Sendai.

Please, register and make reservations by returning the completed form 
by email and fax, following the instructions below.
There will also be on-site registration at:
   * Sendai Tokyu Hotel, 15:00 - 20:00, August 16
   * Aoba Memorial Bldg., Tohoku Univ., 9:00 - 17:00 on August 17 - 19.

Transportation

Conference participants arriving at the new Tokyo International (Narita) 
Airport are advised to take the JR Narita Express train from Narita Airport
to Tokyo Station. 
Then, take the Yamabiko super express train of Tohoku Shinkansen (Tohoku 
Bullet Train) to Sendai from Tokyo Station. The Yamabiko runs every 20 - 30
min. and takes about 2 hours from Tokyo to Sendai. Making reservation at 
Narita Station for the Yamabiko is recommended, since it will be the summer
tourist season. 
Those arriving at the new Osaka International Airport (Kansai Airport) can
fly to Sendai Airport, and take Limousine Bus service to Sendai Station. 
The bus takes about 30 min. to go from the Airport to Sendai Station. You 
can also take a shuttle bus service from Kansai Airport to the Osaka-Itami 
Airport to fly from there to Sendai Airport. Alternatively, you can take a 
local train from the Kansai Airport to JR Shin Osaka Station, then take the
Tokaido Shinkansen from Osaka to Tokyo Station and change at Tokyo Station 
to Tohoku Shinkansen. 
Some details on transportation will be available on the TCS2000 Web page, at
        http://tcs2000.ito.ecei.tohoku.ac.jp/tcs2000/
Note: 
(1) In Japan, mid-August is the busiest tourist time during summer, 
    including domestic and international flights. 
(2) No flight service is available from Narita to Sendai Airport, since the
    train service is convenient. There is another train service from Narita
    Airport to downtown Tokyo (Ueno) by Skyliner of the Keisei-Narita Line.
    At Ueno you can take the Yamabiko super express of Tohoku Shinkansen to
    Sendai, but you have to walk about 10 min. from Keisei-Ueno Station to 
    JR Ueno Station to take Tohoku Shinkansen.
(3) If you are going to travel in Japan by JR lines before/after the IFIP 
    TCS2000 conference, it will be convenient and economical to get a JR 
    PASS before your departure. Contact your travel agent for more 
    information on JR PASS (Japan Rail Pass).

Hotels

Two hotels are arranged to offer special discount rates to IFIP TCS2000 
participants: Sendai Tokyu Hotel and Sendai Washington Hotel. They are 
1.2 km west of Sendai Station and about 800 Yen by taxi from the station. 
These hotels are located within 5 min. walk from each other. The conference
welcome reception and banquet will be held at Sendai Tokyu Hotel.

Sendai and Climate

Sendai is the largest city in the northern part of the Honshu Island of 
Japan, with a population of about a million. The City is known in Japan 
as "City of Trees". Sendai is a modern, safe city with a temperate climate 
blessed by four distinct seasons; even in mid August it is quite seldom 
that the highest temperature exceeds 30 C (86 F). 
Usually, the weather in mid August would be mostly sunny with temperatures
ranging from 20 C (68 F) to 30 C (86 F), and rain, if any, would rarely be
heavy.
Note: Average temperatures in August at Sendai, Tokyo and Osaka are about 
      23.5 C, 26.5 C and 27.5, respectively.

REGISTRATION AND RESERVATION INFORMATION
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                                                                            
REGISTRATION FEES

Registration fees cover attendance in all sessions, a copy of the proceedings, 
refreshments, the welcome reception and banquet, but not the Japanese dinner 
party on August 19. The reduced author rate applies to all authors of the 
accepted papers, and the reduced committee member rate applies to all TC1 
members and to all members of the Program Committee and the Organizing 
Committee. The student rate applies to full time students. Registrants paying
reduced rates have full privileges at the conference. The companion rate 
covers the reception and banquet only.

                      Through July 1st, 2000          From July 2nd, 2000 
   Regular                  40,000 Yen                    50,000 Yen
   Author                   30,000 Yen                    40,000 Yen
   Committee Member         30,000 Yen                    40,000 Yen
   Student                  25,000 Yen                    30,000 Yen
   Companion                 5,000 Yen                     7,000 Yen

HOTELS

Two convenient Western Style hotels offer special IFIP TCS2000 discount rates.
Rates are per person, per night, and include service charge and tax (not 
including breakfast).

                                    Single Room           Twin Room
   Sendai Tokyu Hotel               10,500 Yen            8,400 Yen
   Sendai Washington Hotel II        8,400 Yen            7,350 Yen
   Sendai Washington Hotel I         7,350 Yen            ---------

Note: Twin room reservations are available for two persons. No roommate 
      matching service is available, so that twin room reservations remain 
      the registrant's responsibility.
 
JAPANESE DINNER PARTY

A Japanese dinner party for participants from abroad will be arranged at
SHOZANKAN in the evening of August 19. The invited speakers, some Steering
Committee members, PC members and conference organizers will attend. A 
limited number of reservations will be available for this dinner party. 
The rates are as follows.

   Conference registrant:   10,000 Yen
   Companion:                7,000 Yen

=============================================================================
Cut here to send your registration form after filling in the required items.
=============================================================================

IFIP TCS2000 REGISTRATION AND RESERVATION FORM
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Please register and make reservations by completing the form below and 
returning it by email to

        tcs02@REDACTED

Registrants are advised to email a copy of their completed form to

        TCS2000@REDACTED

They are also encouraged to send a signed, printed copy of their completed 
form by fax to

        022-262-5002 (domestic)
     +81-22-262-5002 (from abroad)

which is the fax number of the following agent to take care of the conference
registration and reservation.

    JTB (Japan Travel Bureau) Tohoku Communications Inc.
    Kotsukosha Bldg 3F, 3-6-Chuo
    Aoba-Ku, Sendai 980-0021, Japan

    (Fax)   022-262-5002 (domestic)
            +81-22-262-5002 (from abroad)
    (Phone) 022-262-5055 (domestic)
            +81-22-262-5055 (from abroad)
    (Email) tcs02@REDACTED

Registration and reservations will be completed by your payment, whose method
is described below.

IMPORTANT NOTE: As described below, from the standpoint of the safety, 
    registrants are advised to pay fees by Bank Transfer. When the payment is
    made by a credit card, they are advised to send the required information 
    including Credit Card numbers by FAX; that is, do NOT send Credit Card 
    numbers by email.
  
REGISTRATION FOR IFIP TCS2000
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  Last (Family) Name:

  First (Given) Name:

  Middle:

  Affiliation:

  Postal Address:

  City/State/Zip:

  Country:

  Phone:

  Fax:

  Email:

  Registration Status 
    <Regular, Author, Committee Member, Student>:

  Number of Companions:

  Companions' names (if applicable):

  (A) Total Registration Fee(s) in Yen:

HOTEL RESERVATION

  Hotel First Choice:

  Hotel Second Choice:

  Number of Single Room(s):

  Number of Twin Room(s):

  Roommate's Name(s) for Twin Room(s):

  Check-in Date:

  Check-out Date:

  Number of Nights:

  Special Room or other Request:

JAPANESE DINNER PARTY

  A limited number of reservations are available for the Japanese dinner 
  party at SHOZANKAN on August 19 to be arranged for participants from 
  abroad.

  (B) 10,000 Yen x [   ] conference registrant(s):

  (C)  7,000 Yen x [   ] companion(s):

TOTAL FEE IN YEN

  (A) + (B) + (C):

Signature (not needed for email):

METHOD OF PAYMENT FOR IFIP TCS2000

   From the standpoint of the safety and security, participants are encouraged
   to pay via Bank Transfer. When they pay via credit card, they are advised 
   to send the required information (in particular, Credit Card numbers) by 
   FAX; that is, do NOT send your Credit Card numbers by email. 
   In credit card payment Visa card, MasterCard, and Diners card will be 
   accepted. Personal checks cannot be accepted.
   All payments must be made in Japanese Yen.

Indicate method of payment below:

  [    ] Bank Transfer to

              Bank: Tokyo Mitsubishi Bank, Sendai Branch
              Account Name: IFIP TCS2000 Chair Takayasu Ito
              Account No. 1108671  

         From <bank name>:

         Date of transfer:

         Payer's name:

         Note: In Japan the bank number of Tokyo Mitsubishi Bank is 0005, and
               the number of its Sendai Branch is 320.

  [    ] Payment by Credit Card

         Credit Card Type <Visa, MasterCard, or Diners>:

         Card Number:

         Expiration Date:

         Signature (not needed for email):
                                                                              
  <Note>: When your payment is via Credit Card, send the above information
          by FAX to +81-22-262-5002, the fax no. of JTB Communications Inc. 
          Even when you send the above form by fax, send it by EMAIL 
          without  filling in Credit Card number for safety.
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Registration and reservations will be confirmed upon receipt of payment.
Refunds will be made upon written request received through July 31st, 2000
by JTB Tohoku Communications Inc.









                   

  


        













From nick@REDACTED  Thu Apr 20 10:12:12 2000
From: nick@REDACTED (Niclas Eklund)
Date: Thu, 20 Apr 2000 10:12:12 +0200 (MET DST)
Subject: orber
In-Reply-To: <874s8xqie7.fsf@cockatoo.bluetail.com>
Message-ID: <Pine.GSO.3.96.1000420090318.11131G-100000@shagrat>

On 20 Apr 2000, Luke Gorrie wrote:
> Michael Skowronski <mskow@REDACTED> writes:
> > Hello,
> > 
> > does anyone have a simple example of how to connect a java visibroker
> > client to an orber service?
> 
> I have, though I used JacORB rather than
> Visibroker. http://203.46.39.99:2000/get?node=orber+quickstart
> Cheers,
> Luke

Hello!

Another way to setup a connection is to use InitialReferences.idl and
follow the example in Orber user's guide 9, but don't compile
cos_naming.idl (included since the example is based on OrbixWeb2.*, which
didn't support 'pragma prefix' until 3.*). The code below illustrates a
OrbixWeb3.2 client:



import org.omg.CosNaming.*;
import org.omg.CORBA.*;
import Orber.InitialReference.*;
import Orber.InitialReferences.*;
import org.omg.CORBA.SystemException;
import org.omg.CORBA.ORB.*;

public class Client 
{
  public static void main(String args[])
    {
      NamingContext nsContext;
      org.omg.CORBA.Object nsRef, objRef, initRef;
      Orber.InitialReference ir    = new Orber.InitialReference();
      Orber.InitialReferences init = null;

      String  srvHost   = new String(args[0]);
      Integer srvPort   = new Integer(args[1]);

      try
        {
	  ORB orb   = ORB.init(args, null);

          //The next line equals "reading IOR from file" (see Luke's link)
	  String s  = ir.stringified_ior(srvHost, srvPort.intValue());

	  initRef   = orb.string_to_object(s);
	  init      = Orber.InitialReferencesHelper.narrow(initRef);
	  // Fetch name service reference.
	  nsRef     = init.get("NameService");	  
	  nsContext = NamingContextHelper.narrow(nsRef);

          // Now you can use 'resolve' etc and access objects

... cut ...


The OMG published two preliminary Interoperable-NamingServices; Orber
supports one (IBM's). Unfortunately ;-), the next CORBA specification
contains the one we're currently not supporting. The example above, is
based on the IBM-interoperable naming service (also supported by
JavaIDL, and ...?!).

IMHO, if you intend to start a number of servers, it's easier to just
store just one reference, i.e., the NameService. 

You should also consult:

* Orber User's Guide, 10, "Orber Stubs/Skeletons"

* Orber Refernce Manual, "Module_Interface"

These chapters includes example code on how to implement your
'Module_Interface_impl.erl' file, e.g., functions which must be
implemented. Depending on what type of server you intend to implement, it
may be a good idea to use oe_create_link/2 or oe_create/2. The second
argument, 'Options', is usefull (and more features to come :-).

BR/Nick





From matthias@REDACTED  Thu Apr 20 11:34:16 2000
From: matthias@REDACTED (matthias@REDACTED)
Date: Thu, 20 Apr 2000 11:34:16 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <200004192227.e3JMR9I08267@super.du.uab.ericsson.se>
References: <14589.13954.505029.822433@eddieware.eddieware.org>
	<200004192227.e3JMR9I08267@super.du.uab.ericsson.se>
Message-ID: <14590.53016.840927.933044@gargle.gargle.HOWL>


 > Pekka.Hedqvist@REDACTED wrote:

 > >When trying to measure time we get really weird values from the
 > >'erlang:now()' when two successive calls to it are done with less than
 > >100 microseconds between the two calls. The values are far too low; 0,
 > >1 microseconds are reported even when maybe 60-80 has passed. If the

Per writes:

 > Do you really ever see a difference of 0 microseconds? That would be a
 > serious bug, monotonically increasing values is just about the only
 > thing erlang:now() *really* promises to produce. 

Careful! "monotonic" doesn't mean what you use it to mean, I think. (*)

The authors of the standard erlang spec write:

    A 3-tuple of integers is returned that is guaranteed to be
    different for each invocation on a node.
    [...]
    Two calls of the BIF now() by a processes residing on the same
    node can never return the same term.
    [...]
    (footnote)However, the time might be inaccurate if several calls
    are made within a microsecond.	

The behaviour Pekka is seeing is wrong, though I think that the
uniqueness requirement on now() should be removed. If you want
something unique, use make_ref(). If you want to know the time, call
now() (or time()).

I can imagine future hardware where keeping now() both unique from
call to call AND more or less representing the time becomes difficult.

---

* As to meaning of monotonic...

The erlang man page for now() doesn't say "monotonic", it says
"continously increasing". I'll leave it to your imagination what that
means when you're talking about a discrete function...

monotonic, according to my recollections from uni and also Cormen, 
Leiserson & Rivest, "Introduction to Algorithms", p.32 means

	 A function f(n) is monotonically increasing if m =< n imples
	 f(m) =< f(n).

The implicit argument to now() is "the time", so to satisfy
monotonically increasing, I could implement now() as

      now() -> {0,0,0}

This confusion about the meaning of "monotonically increasing" seems
widespread in computer science, e.g. both RFC2747 and RFC1644 use it
when they mean "strictly increasing". Does anyone know where this
(wrong?) use originated?

Matthias



From etxuwig@REDACTED  Thu Apr 20 13:24:30 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Thu, 20 Apr 2000 13:24:30 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <14590.53016.840927.933044@gargle.gargle.HOWL>
Message-ID: <Pine.GSO.4.10.10004201315420.13903-100000@avc303>

On Thu, 20 Apr 2000 matthias@REDACTED wrote:

>The behaviour Pekka is seeing is wrong, though I think that the
>uniqueness requirement on now() should be removed. If you want
>something unique, use make_ref(). If you want to know the time, call
>now() (or time()).

This is a tricky issue, and it's certainly compounded by the fact 
that erlang:now() *is* used both for unique IDs and for time 
representation. There are basically two reasons for this:

- make_ref() does not generate a *persistently* unique identifier.
  It is only temporarily unique (hopefully for as long as it is
  referenced.) In contrast, {node(), erlang:now()} is an example
  of a persistently unique global ID - in part due to the uniqueness
  requirement on erlang:now() (*)

- erlang:now() is currently the only way to get a timestamp with 
  sub-second accuracy in Erlang.

>I can imagine future hardware where keeping now() both unique from
>call to call AND more or less representing the time becomes difficult.

I would like to see a new function, e.g. hrtime(), in Erlang, and 
a shift in focus of erlang:now() to become a (strictly increasing)
internal real-time clock. It is vital that Erlang has a sense of 
time that keeps ticking in one distinct direction, regardless of
what the system clock says. 

/Uffe

(*) Of course, one can upset this as well by stopping the node,
setting back the time, and then restarting the node. Oh well...
-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44



From per@REDACTED  Thu Apr 20 13:45:16 2000
From: per@REDACTED (Per Hedeland)
Date: Thu, 20 Apr 2000 13:45:16 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <14590.53016.840927.933044@gargle.gargle.HOWL>
References: <14590.53016.840927.933044@gargle.gargle.HOWL>
Message-ID: <200004201145.NAA04888@aalborg.du.uab.ericsson.se>

matthias@REDACTED wrote:
>Per writes:
>
> > Do you really ever see a difference of 0 microseconds? That would be a
> > serious bug, monotonically increasing values is just about the only
> > thing erlang:now() *really* promises to produce. 
>
>Careful! "monotonic" doesn't mean what you use it to mean, I think. (*)

Sorry, yes I meant "strictly" of course, but you managed to figure that
out anyway.:-)

>The behaviour Pekka is seeing is wrong, though I think that the
>uniqueness requirement on now() should be removed. If you want
>something unique, use make_ref(). If you want to know the time, call
>now() (or time()).

The advantage of the current implementation, in addition to those that
Ulf mentions, is that it makes it possible to strictly(:-) order
timestamped events (within a node) - if I recall correctly, this was the
original motiviation for implementing it at all, the relation to
wall-clock time was even more vaguely specified back then.

>I can imagine future hardware where keeping now() both unique from
>call to call AND more or less representing the time becomes difficult.

Oh well, we can just go to nanoseconds and squeeze a few more years out
of it.:-)

--Per Hedeland
per@REDACTED


From thomas@REDACTED  Thu Apr 20 13:52:30 2000
From: thomas@REDACTED (Thomas Arts)
Date: Thu, 20 Apr 2000 13:52:30 +0200
Subject: erlang:now() in erlang 4.9.1 on Linux
References: <Pine.GSO.4.10.10004201315420.13903-100000@avc303>
Message-ID: <38FEEF7E.1E02DDDF@cslab.ericsson.se>

Ulf Wiger wrote:


> This is a tricky issue, and it's certainly compounded by the fact
> that erlang:now() *is* used both for unique IDs and for time
> representation. There are basically two reasons for this:
> 
...

> I would like to see a new function, e.g. hrtime(), in Erlang, and
> a shift in focus of erlang:now() to become a (strictly increasing)
> internal real-time clock. It is vital that Erlang has a sense of
> time that keeps ticking in one distinct direction, regardless of
> what the system clock says.

The problem cannot be solved by introducing a new function. The fact that
now() presents the time in microseconds automatically implies that calls
within microseconds will return the same value. If hardware gets faster,
the risk of returning the same value increases.
Sure, one can introduce pico-seconds, postponing the discussion for 9.5 years,
but that on itself does not solve the problem. One needs to be able to
guarantee increments.

My first intuition is that one needs to guarantee the function now() to have an
execution time at least the smallest time that it can measure. Thus, if one
executes now() on a very fast machine, it should at least take a microsecond.
If the machine is too fast for that, let now() wait! Compile the runtime system 
on a target machine and put a special constant in for now() to wait. This seems
like a terrible waist of cpu time, but it is only necessary on machines that are
faster than now()'s accuracy. If one is waiting too much, one increases the 
precision.

Another thing one could try is to add a clocktick system. Whenever the runtime
system is executing a "symbolic" instruction, the clocktick is increased. I guess
one needs 8 bytes or such to have a reasonable representation, need not be more
than the expected livetime of hardware ;0). The bytes are read when ticks() is
evaluated and that gives a guaranteed increment. However, every instruction
(or a special kind, e.g. every read from the heap) is slower since it should add
1 to the 8 bytes in memory.

/Thomas


From etxuwig@REDACTED  Thu Apr 20 14:25:44 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Thu, 20 Apr 2000 14:25:44 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <38FEEF7E.1E02DDDF@cslab.ericsson.se>
Message-ID: <Pine.GSO.4.10.10004201356470.13903-100000@avc303>

On Thu, 20 Apr 2000, Thomas Arts wrote:

>Ulf Wiger wrote:
>
>
>> This is a tricky issue, and it's certainly compounded by the fact
>> that erlang:now() *is* used both for unique IDs and for time
>> representation. There are basically two reasons for this:
>> 
>...
>
>> I would like to see a new function, e.g. hrtime(), in Erlang, and
>> a shift in focus of erlang:now() to become a (strictly increasing)
>> internal real-time clock. It is vital that Erlang has a sense of
>> time that keeps ticking in one distinct direction, regardless of
>> what the system clock says.
>
>The problem cannot be solved by introducing a new function. The fact that
>now() presents the time in microseconds automatically implies that calls
>within microseconds will return the same value. If hardware gets faster,
>the risk of returning the same value increases.

Actually, introducing the new function was meant to solve the problem
that people need to use erlang:now() today in order to get sub-second
time accuracy. In most cases, one couldn't care less about
microseconds (knowing that the system time isn't that accurate
anyway!), but 1/1000, 1/100, 1/10 are useful quite often.
Naturally, for a hi-res clock, it would be quite logical to get the
same answer twice in a row, if the calls are close enough, and
if hrtime() had millisecond accuracy, it would indeed happen.
Of course, if it would return {Hr,Min,Sec}, where Sec : float(),
the precision could vary on different systems.

(With today's hardware, and using NTP, you can rely on your system
clock being accurate within a few milliseconds. A built-in GPS
circuit ought to be able to reach microsecond accuracy, I think...)

Currently, now() is used both as a "clocktick" counter and a hi-res
clock. This is unfortunate.

/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44



From Sean.Hinde@REDACTED  Thu Apr 20 21:56:08 2000
From: Sean.Hinde@REDACTED (Sean Hinde)
Date: Thu, 20 Apr 2000 20:56:08 +0100
Subject: New timer app
Message-ID: <402DD461F109D411977E0008C791C312564DA9@imp02mbx.one2one.co.uk>

Ulf,

> Sean>I recently posted a little application derived from the
> Sean>standard timer module in Kernel which uses an ordered_set
> Sean>mnesia table with a couple of indeces to give something
> Sean>which is more scalable.

> I must have dozed off for a while -- I didn't realize what you'd 
> done until now.
> I've attached our sysTimer module for your perusal.

I have perused, and see that the erlang:start_timer BIF is a good thing.

I'm not so sure about spawning a process for every apply_after though. I
have an application in mind which might have 100000 timers running, and
having a new process for each one is likely to be a pretty large overhead.
In more normal applications I'm not that sure which would be best. It
dependes on the source of inefficiency in the standard timer.

If your finding was that adding to the end of a sorted list was the problem
then mine sorts this out. If it was in the extra overhead of message passing
to a gen_server then fair enough.. ?

BR,
Sean 


From matthias@REDACTED  Fri Apr 21 04:37:01 2000
From: matthias@REDACTED (matthias@REDACTED)
Date: Thu, 20 Apr 2000 21:37:01 -0500 (CDT)
Subject: Scheme and Functional Programming 2000
Message-ID: <200004210237.VAA16691@africa.cs.rice.edu>


		[-- Apologies for multiple copies --]

============================================================================

                      PRELIMINARY CALL FOR PAPERS

                   Scheme and Functional Programming

                   Montreal, Canada, 17 September 2000

         The workshop forms part of PLI 2000, which consists 
         of the ICFP and PPDP conferences and other workshops.

             http://www.cs.rice.edu/~matthias/Scheme2000/

============================================================================

Background and Theme:
---------------------

   Over the past few years, Scheme and its implementations have made
   tremendous progress in support of generative programming, shell
   scripting, COMponent support and distributed programming, graphics
   and GUI support, OO programming, and various other aspects of
   engineering real-world software. We are calling on implementors and
   users of Scheme systems to share their ideas at a workshop during
   PLI 2000 in Montreal.

   The organizers goal is to attract presentations on a broad spectrum
   of topics:

    * applications 
    * environments 
    * extensions 
    * implementations 
    * logics (predicate types)
    * programs

   The committee will consider submissions concerning Scheme and other
   functional languages  (Erlang, Haskell, LISP, ML, XML, etc.).

Submission details
------------------

   Deadline for submission:      15 June 2000  
 
   The organizers seek two kinds of presentations:
   
    * regular: These presentations are like conventional workshop and
        conference presentation.

    * short: These presentations last up to 15 mins and are on
	unconventional topics. Examples include unusual applications,
	nifty Scheme programming tricks, ideas on implementations,
	designs and requests for implementations, etc.

Program committee
------------------

   Kent Dybvig, Indiana University
   Marc Feeley, Universit? de Montr?al
   Matthias Felleisen, Rice University
   Daniel Friedman, Indiana University
   Manuel Serrano, Universit? de Nice (Sophia-Antipolis)
   Olin Shivers, Massachusetts Institute of Technology

Details
-------
  
   http://www.cs.rice.edu/~matthias/Scheme2000/

============================================================================



From geoff@REDACTED  Sat Apr 22 05:43:51 2000
From: geoff@REDACTED (Geoff Wong)
Date: Sat, 22 Apr 2000 13:43:51 +1000 (EST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <14590.53016.840927.933044@gargle.gargle.HOWL> from "matthias@besserwisser.org" at Apr 20, 2000 11:34:16 AM
Message-ID: <200004220343.DAA20511@gecko.serc.rmit.edu.au>


> Per writes:
> 
>  > Do you really ever see a difference of 0 microseconds? That would be a
>  > serious bug, monotonically increasing values is just about the only
>  > thing erlang:now() *really* promises to produce. 
> 
> Careful! "monotonic" doesn't mean what you use it to mean, I think. (*)
> 
> The authors of the standard erlang spec write:
> 
>     A 3-tuple of integers is returned that is guaranteed to be
>     different for each invocation on a node.
>     [...]
>     Two calls of the BIF now() by a processes residing on the same
>     node can never return the same term.
>     [...]
>     (footnote)However, the time might be inaccurate if several calls
>     are made within a microsecond.	
> 
> The behaviour Pekka is seeing is wrong, though I think that the
> uniqueness requirement on now() should be removed. If you want
> something unique, use make_ref(). If you want to know the time, call
> now() (or time()).

Sub-microsecond timing isn't currently our problem. But as Per (I think)
demonstrated timing is all "jumpy" when sub < 100 us.

We originally noticed the problem when I was timing "HEAD /" requests
off web servers. I was getting utterly bizarre timings off
our fast machines (1 us for web page delivery - wow - I wish :),
I spent ages trying to work out what was wrong with my code
before i realised it was the timer.

Obviously sub-microsecond execution might be an issue someday soon
(but even an optimised C loop that does a system call like fprintf()
is unlikely to go below a 1 us). Anyway, the current erlang:now() 
(for Linux) is seriously flawed and should be fixed (and or eradicated;
perhaps a different fix should be implemented for system time changes). 

It was probably a plot by FreeBSD guys somewhere in the development
process to discredit Linux :-)

Geoff




From bjarne@REDACTED  Sat Apr 22 11:33:39 2000
From: bjarne@REDACTED (Bjarne Däcker)
Date: Sat, 22 Apr 2000 11:33:39 +0200
Subject: Scheme and Functional Programming 2000
References: <200004210237.VAA16691@africa.cs.rice.edu>
Message-ID: <390171F3.1028EC16@erix.ericsson.se>

Hello Matthias

This is just to inform you that I plan to
submit a paper on the development and use
of Erlang.

Joe Armstrong wrote some good papers on the
developments up to about 1997, please see
under

http://www.erlang.se/publications/index.shtml

but since then lots has happened notably
'open source'

http://www.erlang.org/

Just now I am trying to collect information
from users about code sizes, systems delivered
etc but some of this information might be
confidential. (I will be grateful for anybody 
reading this having interesting information
would get in contact with me.)

Thank you for including Erlang among your
favourite programming languages.

Happy Easter

Bjarne

=====================================

Computer Science Laboratory
Ericsson Utvecklings AB
PO Box 1505
125 25 ?lvsj?
Sweden


From per@REDACTED  Sat Apr 22 12:32:13 2000
From: per@REDACTED (Per Hedeland)
Date: Sat, 22 Apr 2000 12:32:13 +0200 (MET DST)
Subject: erlang:now() in erlang 4.9.1 on Linux
In-Reply-To: <200004220343.DAA20511@gecko.serc.rmit.edu.au>
References: <200004220343.DAA20511@gecko.serc.rmit.edu.au>
Message-ID: <200004221032.e3MAWDY00903@super.du.uab.ericsson.se>

Geoff Wong <geoff@REDACTED> wrote:
> Anyway, the current erlang:now() 
>(for Linux) is seriously flawed and should be fixed (and or eradicated;
>perhaps a different fix should be implemented for system time changes). 

Eradicating erlang:now() isn't an option I think:-), but of course its
behaviour on Linux should be fixed - note though that I already told you
how to "fix" it to become as good as (e.g.:-) FreeBSD at least: Just
recompile without CORRECT_USING_TIMES defined.

>It was probably a plot by FreeBSD guys somewhere in the development
>process to discredit Linux :-)

:-) Actually the conscious plot would have made Linux look better than
FreeBSD, as it would have had the "soft adjustment" of Erlang time when
system time jumped. CORRECT_USING_TIMES was at one point defined for
everything that didn't have gethrtime() but had times() - however we
learned that times() on FreeBSD was just a wrapper around gettimeofday()
(and getrusage()), making the adjustment excercise futile of course.

So, it was decided to only use CORRECT_USING_TIMES if the OS was *known*
to have a "real" times(), i.e. one that kept ticking independent of
system time - and Linux happened to be the only one that fitted that
bill. Unfortunately it seems the actual logic of the CORRECT_USING_TIMES
case didn't undergo quite as detailed testing as the gethrtime() case
(plus of course the logic is trickier due to the low resolution of
times()).

--Per Hedeland
per@REDACTED


From etxuwig@REDACTED  Tue Apr 25 09:20:42 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Tue, 25 Apr 2000 09:20:42 +0200 (MET DST)
Subject: New timer app
In-Reply-To: <402DD461F109D411977E0008C791C312564DA9@imp02mbx.one2one.co.uk>
Message-ID: <Pine.GSO.4.10.10004250917420.23625-100000@avc303>

On Thu, 20 Apr 2000, Sean Hinde wrote:

>Ulf,
>
>> Sean>I recently posted a little application derived from the
>> Sean>standard timer module in Kernel which uses an ordered_set
>> Sean>mnesia table with a couple of indeces to give something
>> Sean>which is more scalable.
>
>> I must have dozed off for a while -- I didn't realize what you'd 
>> done until now.
>> I've attached our sysTimer module for your perusal.
>
>I have perused, and see that the erlang:start_timer BIF is a good thing.
>
>I'm not so sure about spawning a process for every apply_after though. I
>have an application in mind which might have 100000 timers running, and
>having a new process for each one is likely to be a pretty large overhead.
>In more normal applications I'm not that sure which would be best. It
>dependes on the source of inefficiency in the standard timer.
>
>If your finding was that adding to the end of a sorted list was the problem
>then mine sorts this out. If it was in the extra overhead of message passing
>to a gen_server then fair enough.. ?

It was really a combination of the two.
If your application requires that many timers, you may indeed have to
invent something new, as you have done.

/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44




From bud@REDACTED  Thu Apr 27 18:32:48 2000
From: bud@REDACTED (Bud P. Bruegger)
Date: Thu, 27 Apr 2000 18:32:48 +0200
Subject: requirements of health care apps
Message-ID: <3.0.6.32.20000427183248.009096b0@mail.sistema.it>

Dear Erlangers:

I'm highly interested in using Mnesia/Erlang for an open source laboratory
information system.  We (Sistema and the joint FAO/IAEA division) plan to
get together a consortium to develop such a system.  In this context, we
have discussed the suitability of Mnesia/Erlang on the openhealth mailing
list.  

This discussion has identified some limitations of Mnesia/Erlang in respect
to health care applications that I hope can be overcome.  I would be very
grateful if you could give me information on the possibility and necessary
effort/time to overcome these limitations.  

Also, there are two killer apps that I imagine could work well with
Mnesia/Erlang.  I briefly describe them below and hope that someone could
give me some feedback on how well Mnesia/Erlang are suited for the purpose.

Limiations:
===========

1. Limit of Mnesia databases to a size of 4GB
(http://www.erlang.org/faq/x1084.html#AEN1103).  Competing dbms usually
handle terrabyte of data.  Is there an easy fix?  Does this limitation
apply to a single node in a distributed setting or to the whole database?

2. inefficient handling of text 
(http://www.erlang.org/faq/x299.html#AEN309).  Many health care
applications make heavy use of free-text style data (such as medical
records) that are if possible losely structures (with XML).  How difficult
would it be to extend Mnesia/Erlang to efficiently store and manage
(regular expressions, free text search etc.) textual data?  The FAQ
mentions work underway.  Will this only apply to Erlang or also Mnesia?
Does anyone know when to expect the results to be available?


Killer Apps:
============

1. Persistent Object Store
--------------------------

Many health care applications seem to use some object-oriented
implementation language (often Java) and use an object-relational mapping
that makes objects persistent in a relational DBMS.  The persistance layer
brings a lot of overhead since object access is handled by the persistance
layer, JDBC, SQL interpreter, to finally reach the native representation.
A more detailed description of object-relational mapping can be found in
http://www.objectarchitects.de/ObjectArchitects/orpatterns/index.htm and
http://www.ambysoft.com/persistenceLayer.html.  

My impression is that this approach is way to slow for managing large
numbers of fine grained objects.  (Note that this is generally accepted for
Enterprise Java Bean Container Managed Persistance--a variation of the
above topic).  I looked into object-oriented DBMS as alternatives, but
didn't find anything convincing.  The serious OODBMS are not open sourced,
the open sourced ones are usually simplistic (no redundancy, fail-over,
etc) and yet slow (since written in Java).  

I imagine that Mnesia, being object-relational and very fast, would be a
great backend DBMS for a persistent object store.  The overhead introduced
by a Java persistance layer on top of Mnesia intuitively seems to be less
than that of the "normal" object-relational mapping.  And the distribution
and fault-tolerance features of Mnesia are unique and highly attractive.  

I would be very interested in you opinion on feasibility, performance,
degree of paradigm mismatch, etc.  A practical project could for example
add a Mnesia backend to Castor (http://castor.exolab.org/).  


2. Distributed, fault-tolerant XML Repository
----------------------------------------------

Another killer app (that is admittedly related to the above) would be a
distributed, fault-tolerant xml repository based on Mnesia.  XML is
difficult to map to relational tables (see
http://www.poet.com/products/cms/white_papers/xml/repository.html) and some
approaches use a (IMHO slow) object-relational mapping
(http://www.informatik.tu-darmstadt.de/DVS1/staff/bourret/xmldbms/xmldbms.ht
m) to overcome this problem.  
I would be very interested in your opinion on how well Mnesia would be
suited as a backend for an XML repository.  For example, how easily the
structure of XML would map to Mnesia.  

Looking forward to your feedback

many thanks

--bud
/------------------------------------------------------------------------\
| Bud P. Bruegger, Ph.D.  |  mailto:bud@REDACTED                       |
| Sistema                 |  http://www.sistema.it                       |
| Information Systems     |  voice general: +39-0564-418667              |
| Via U. Bassi, 54        |  voice direct:  +39-0564-418667 (internal 41)|
| 58100 Grosseto          |  fax:           +39-0564-426104              |
| Italy                   |  P.Iva:         01116600535                  |
\------------------------------------------------------------------------/


From jith@REDACTED  Fri Apr 28 01:50:14 2000
From: jith@REDACTED (Jith Meganathan)
Date: Thu, 27 Apr 2000 18:50:14 -0500
Subject: Information hiding in Erlang
Message-ID: <3908D236.1892CC92@vailsys.com>

Hi - I'm a newcomer to Erlang, and have been slowly working through the
_Concurrent Programming in Erlang_ book to learn the language. My
background is mostly in OOP, and thus, one of the aspects of Erlang I am
most uncomfortable with is the apparent lack of support for information
hiding.

I've attached a module I wrote implementing a simple priority queue with
operations to add and pop elements, and to view the element with highest
priority. The data structure used is a list of tuples, where each tuple
contains an element and a priority. In writing the module, I felt a
certain...nervousness at trusting callers to pass in a valid data
structure each time they invoked a function in the module. Does Erlang
provide mechanisms for encapsulating data structures, or is lack of
information hiding just something to be accepted when programming a
functional language?

Potential solutions seem to include the method used in the example
program (Program 5.6) on pp. 81 - 82 of _Concurrent Programming in
Erlang_, in which a server function stores data structures in their
current state, suspends until it receives a message to operate on them,
and after processing, invokes the function with the now-modified data
structures as arguments. I have also seen references to doing OOP in
Erlang, but am unsure of how common this approach is. In short, what is
the most natural mechanism to use in the language?

Regards,
Jith


~~~~~~~~~~~~~
Jith Meganathan
Vail Systems, Inc.
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From jhague@REDACTED  Fri Apr 28 03:21:49 2000
From: jhague@REDACTED (James Hague)
Date: Thu, 27 Apr 00 20:21:49 -0500
Subject: Information hiding in Erlang
Message-ID: <200004280120.UAA01131@node-03.advancenet.net>

> Does Erlang
>provide mechanisms for encapsulating data structures, or is lack of
>information hiding just something to be accepted when programming a
>functional language?

One simple trick is to put an atom in your data structure and check for 
it.  So you could represent a priority queue as {priority_queue, Queue}.  
Then each routine that operated on it could be of the form:

insert({priority_queue, Queue}) -> ...

This isn't bulletproof, but covers you in most cases.  In general, I try 
not to worry too much about such things.  After all, I could have a 
routine that accepted three parameters, all integers, and I can't check 
if the user gets the order wrong.  Some advice I've heard is to avoid 
thinking of other programs in the system as attacking microbes, and 
assume they'll play nice in general :)

Erlang is one of the few functional languages that's dynamically typed.  
In other functional languages there's much formalism to make sure that a 
priority queue is indeed a priority queue, but it's debatable if the 
effort is indeed worth the result.

James


From luke@REDACTED  Fri Apr 28 12:00:30 2000
From: luke@REDACTED (Luke Gorrie)
Date: 28 Apr 2000 12:00:30 +0200
Subject: Information hiding in Erlang
In-Reply-To: Jith Meganathan's message of "Thu, 27 Apr 2000 18:50:14 -0500"
References: <3908D236.1892CC92@vailsys.com>
Message-ID: <87wvlibl4x.fsf@cockatoo.bluetail.com>

Jith Meganathan <jith@REDACTED> writes:

> I've attached a module I wrote implementing a simple priority queue with
> operations to add and pop elements, and to view the element with highest
> priority. The data structure used is a list of tuples, where each tuple
> contains an element and a priority. In writing the module, I felt a
> certain...nervousness at trusting callers to pass in a valid data
> structure each time they invoked a function in the module. Does Erlang
> provide mechanisms for encapsulating data structures, or is lack of
> information hiding just something to be accepted when programming a
> functional language?

You could make an abstract data type out of queue elements with:

qelement({Elt, _Priority})  -> Elt.
qpriority({_Elt, Priority}) -> Priority.

Since it's often useful to use these things as lists anyway, you could
also add:

%% Turn a Queue into an ordered list of {Element, Priority} and vice versa
queue_to_list(Queue) -> Queue.
list_to_queue(List)  -> List.

This should be sufficient to let you change the "internal" data
structure however you want in future. The "dict" module in stdlib
makes a good example, I think.

So, you still don't have compilier- or runtime- checks enforcing
encapsulation, but you do have a way to write clients which doesn't
rely on the format of the list.

Cheers,
Luke



From maurice@REDACTED  Fri Apr 28 04:54:02 2000
From: maurice@REDACTED (Maurice Castro)
Date: Fri, 28 Apr 2000 12:54:02 +1000 (EST)
Subject: Information hiding in Erlang
In-Reply-To: <3908D236.1892CC92@vailsys.com> from Jith Meganathan at "Apr 27,
 2000 06:50:14 pm"
Message-ID: <200004280254.MAA27849@parallel.serc.rmit.edu.au>

Hi All,
	true information hiding in Erlang may be accomplished through the use
of processes. Information to be hidden is held in the process and the
process is acted on by messages, changing the state of the process.
Note: to be polite, you should also provide accessor functions which
format the messages correctly

This structure is typically used where state stores are required or segments
of a system need to be isolated from potentially misbehaving components.

In general, however, there is little value in concerning oneself about
users deliberately misusing a function, they can only hurt themselves by
killing their own process. Any nervousness about interfering with the 
`hidden' inputs to a function are equivalent to worrying about someone
either forgetting to allocate an object or deleting and reallocating an
object in an OO program.

Processes should either protect their interfaces by either guards or
selecting only valid data types; or they should have a restart strategy
incase of failure.

	Maurice Castro


From pan@REDACTED  Fri Apr 28 10:47:53 2000
From: pan@REDACTED (Patrik Nyblom)
Date: Fri, 28 Apr 2000 10:47:53 +0200
Subject: erlang:now() in erlang 4.9.1 on Linux
References: <14590.53016.840927.933044@gargle.gargle.HOWL>, <200004220343.DAA20511@gecko.serc.rmit.edu.au>
Message-ID: <39095039.66A625FD@erix.ericsson.se>

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From hakan@REDACTED  Fri Apr 28 12:29:00 2000
From: hakan@REDACTED (Hakan Mattsson)
Date: Fri, 28 Apr 2000 12:29:00 +0200 (MET DST)
Subject: requirements of health care apps
In-Reply-To: <3.0.6.32.20000427183248.009096b0@mail.sistema.it>
Message-ID: <Pine.GSO.4.05.10004280843550.1441-100000@boddington>

On Thu, 27 Apr 2000, Bud P. Bruegger wrote:

bud>1. Limit of Mnesia databases to a size of 4GB
bud>(http://www.erlang.org/faq/x1084.html#AEN1103).  Competing dbms usually
bud>handle terrabyte of data.  Is there an easy fix?  Does this limitation
bud>apply to a single node in a distributed setting or to the whole database?

The FAQ is partly wrong.

There are no HARD limitations on the maximum database size. 4GB is
the upper limit of one single dets file.

A Mnesia database may consist of lots of tables where each one may use
a dets table as backing storage. In fact you may split your table into
lots of fragments and use dets as backing storage for each fragment.

I would really like to encourage you to perform benchmarks on your own,
using hardware, data volumes and access patterns similar to your
target application. 

There are however two mechanisms in Mnesia, that may probably will
turn out to be showstoppers for your gigantic database:

- repair of dets files. If your systems happens to crash and leave
  a dets file in a opened state, it will automatically recover at
  next startup, but if the file is large it will take ages to repair
  even for rather small dets files. Klacke has suggested a clever
  solution for this (safe dets), this has however not been incorporated
  in Erlang/OTP.

- remote table load. When Mnesia recovers after a node crash, it will
  copy tables from other nodes hosting a more up-to-date replica of
  the table. If the table is large it may take quite a while to transfer
  it between the Erlang nodes. This issue is tricky to solve, without
  major architectural changes of Mnesia.

Storing terrabytes of data in the current Mnesia is not feasible.

But a budget approach, that perhaps would make it possible to use
Mnesia for terrabyte databases, is to extend Mnesia to store blobs as
separate files and only use dets to keep track of the files. This
would dramatically reduce the file size and also make it possible to
use regular tools, such as glimpse, to perform the massive text
search. A new algorithm for replication of blob files could be kept
separate from the current table load algorithm. It would in fact, be
possible to build such a blob replication mechanism as an application
on top of Mnesia, and just use Mnesia to keep track of the meta data,
such as the current replication state.

bud>2. inefficient handling of text 
bud>(http://www.erlang.org/faq/x299.html#AEN309).  Many health care
bud>applications make heavy use of free-text style data (such as medical
bud>records) that are if possible losely structures (with XML).  How difficult
bud>would it be to extend Mnesia/Erlang to efficiently store and manage
bud>(regular expressions, free text search etc.) textual data?  The FAQ
bud>mentions work underway.  Will this only apply to Erlang or also Mnesia?
bud>Does anyone know when to expect the results to be available?

Not this year.

bud>I imagine that Mnesia, being object-relational and very fast, would be a
bud>great backend DBMS for a persistent object store.  The overhead introduced
bud>by a Java persistance layer on top of Mnesia intuitively seems to be less
bud>than that of the "normal" object-relational mapping.  And the distribution
bud>and fault-tolerance features of Mnesia are unique and highly attractive.  
bud>
bud>I would be very interested in you opinion on feasibility, performance,
bud>degree of paradigm mismatch, etc.  A practical project could for example
bud>add a Mnesia backend to Castor (http://castor.exolab.org/).  

Mnesia is a DBMS for Erlang applications. Using Mnesia from other
languages implies that you introduce quite large extra overhead for
process communication (as normal Erlang applications executes in
separate lightweight threads in the same address space as Mnesia) and
data conversion between Java's data structures and Erlang terms.

There are some showstoppers for a Castor backend project, but if you
could live without SQL, XML and text searching this could be an
interesting approach to exploit:

- store the Java data structures in Mnesia as blobs, without converting 
  them to Erlang's datastructures.

- open up Mnesia's inter-node interface and let the Java side act as
  a limited Erlang node running a minimal Mnesia complient server
  without own table replicas.

The performance would of course not be as good as for Erlang applications,
but it could still be acceptable depending on the application requirements.

bud>2. Distributed, fault-tolerant XML Repository
bud>----------------------------------------------
bud>
bud>Another killer app (that is admittedly related to the above) would be a
bud>distributed, fault-tolerant xml repository based on Mnesia.  XML is
bud>difficult to map to relational tables (see
bud>http://www.poet.com/products/cms/white_papers/xml/repository.html) and some
bud>approaches use a (IMHO slow) object-relational mapping
bud>(http://www.informatik.tu-darmstadt.de/DVS1/staff/bourret/xmldbms/xmldbms.ht
bud>m) to overcome this problem.  
bud>I would be very interested in your opinion on how well Mnesia would be
bud>suited as a backend for an XML repository.  For example, how easily the
bud>structure of XML would map to Mnesia.  

In order to achieve acceptable performance, new features needs to
first be added to the Erlang run-time system, then used by Mnesia and
eventually by Mnemosyne:

- searching in lists in ets+dets tables
- regexp searching in binaries in ets+dets tables
- allowing operators like (>, /= etc.) in dets patterns
- asynchronous or threaded I/O
- ...

When this support is included in Erlang/OTP I believe that it would be 
quite easy to build an XML repository on top of Mnesia. It would really
be a killer app.

/H?kan




From bob@REDACTED  Fri Apr 28 14:49:25 2000
From: bob@REDACTED (Bob)
Date: Fri, 28 Apr 2000 02:49:25 -1000
Subject: requirements of health care apps
Message-ID: <200004281249.e3SCnum23305@hades.cslab.ericsson.net>



> 
> 1. Limit of Mnesia databases to a size of 4GB
> (http://www.erlang.org/faq/x1084.html#AEN1103).  Competing dbms usually
> handle terrabyte of data.  Is there an easy fix?  Does this limitation
> apply to a single node in a distributed setting or to the whole database?
> 

Let's remember to distinguish between the soft real time characteristics of mnesia, and the non-real time characteristics of
'competing' dbms.  

One approach is to interface erlang with a 'competing' dbms to leverage the benefits of mnesia for the data requiring soft-real
time, with the benefits of a non-real time sql database.

In the practical application, you'll almost certainly want your terabyte database on machine(s) seperate from your erlang
application.

Thanks to all for great discussion.

Bob


From etxuwig@REDACTED  Fri Apr 28 16:49:52 2000
From: etxuwig@REDACTED (Ulf Wiger)
Date: Fri, 28 Apr 2000 16:49:52 +0200 (MET DST)
Subject: requirements of health care apps
In-Reply-To: <Pine.GSO.4.05.10004280843550.1441-100000@boddington>
Message-ID: <Pine.GSO.4.10.10004281314110.27256-200000@avc303>

On Fri, 28 Apr 2000, Hakan Mattsson wrote:

hakan>There are however two mechanisms in Mnesia, that may probably will
hakan>turn out to be showstoppers for your gigantic database:
hakan>
hakan>- repair of dets files. If your systems happens to crash and leave
hakan>  a dets file in a opened state, it will automatically recover at
hakan>  next startup, but if the file is large it will take ages to repair
hakan>  even for rather small dets files. Klacke has suggested a clever
hakan>  solution for this (safe dets), this has however not been incorporated
hakan>  in Erlang/OTP.
hakan>
hakan>- remote table load. When Mnesia recovers after a node crash, it will
hakan>  copy tables from other nodes hosting a more up-to-date replica of
hakan>  the table. If the table is large it may take quite a while to transfer
hakan>  it between the Erlang nodes. This issue is tricky to solve, without
hakan>  major architectural changes of Mnesia.

In my experience, local table load is also inefficient on very large
tables, unless you keep the table as a disc_only copy (i.e. do not
load it into RAM.) This currently means that you can not make the
table an ordered set (since this exists in ets only - not dets.)

I recently had an ordered_set table with 2 million objects (roughly
500 MB). It took 36 hours to load -- without repair -- on my 330 MHz
UltraSPARC. Granted, the table resided on the file server, but I don't
think the load time would have been in the order of minutes anyway.

Just to get a grip of how long it takes in general to write objects to
a (plain) file, and then read them into an ets table, I wrote a tiny
test program. Putting the file on the same file server as above, I
got:

1000 objects (payload: lists:seq(1,500)):

write: 119 msec (??)
read : 2.5 sec

10,000 objects:

write: 14 sec
read : 25 sec

100,000 objects (174 MB):

write: 168 sec (2 min 48 sec)
read : 433 sec


I didn't run a million objs, but I can guess from the above that it
would take >2500 secs (42 minutes) to read. Even when reading 100,000
objects, my 512 MB Ultra got into some heavy swapping, as the VM grew
to 480 MB (see -- another problem right there).

Conclusion? I think we need to invent some form of large-file I/O, and
an efficient way of dumping a large file into ets, and back.
For the time being, we should use other DBMSes for really large
tables, and let mnesia handle small-to-medium size real-time
databases.

I've attached my simple test program, so you can see what I did.

/Uffe
-- 
Ulf Wiger, Chief Designer AXD 301         <ulf.wiger@REDACTED>
Ericsson Telecom AB                          tfn: +46  8 719 81 95
Varuv?gen 9, ?lvsj?                          mob: +46 70 519 81 95
S-126 25 Stockholm, Sweden                   fax: +46  8 719 43 44

-------------- next part --------------
-module(dbtest).

-compile(export_all).



write(N, F) ->
    {ok, Fd} = file:open(F, [write]),
    Bin = term_to_binary(data()),
    Sz = size(Bin),
    io:format("write Sz = ~p~n", [Sz]),
    do_write(1, N, Bin, Fd),
    file:close(Fd).

do_write(N, NMax, Data, Fd) when N =< NMax ->
    file:write(Fd, list_to_binary([i32(N),Data])),
    do_write(N+1, NMax, Data, Fd);
do_write(N, NMax, Data, Fd) ->
    ok.


i32(Int) when binary(Int) ->
    i32(binary_to_list(Int));

i32(Int)  when integer(Int) -> [(Int bsr 24) band 255,
                                (Int bsr 16) band 255,
                                (Int bsr  8) band 255,
                                Int band 255];
i32([X1,X2,X3,X4]) ->
    (X1 bsl 24) bor (X2 bsl 16) bor (X3 bsl 8) bor X4.

i32(X1,X2,X3,X4) ->
    (X1 bsl 24) bor (X2 bsl 16) bor (X3 bsl 8) bor X4.

read(F) ->
    {ok, Fd} = file:open(F, [read]),
    T = ets:new(?MODULE, [set]),
    Sz = size(term_to_binary(data()))+4,
    io:format("read Sz = ~p~n", [Sz]),
    do_read(Fd, Sz, T).

do_read(Fd, Sz, T) ->
    case file:read(Fd, Sz) of
	{ok, [B1,B2,B3,B4|Bytes]} ->
	    Obj = binary_to_term(list_to_binary(Bytes)),
	    ets:insert(T, {i32([B1,B2,B3,B4]), Obj}),
	    do_read(Fd, Sz, T);
	Other ->
	    {T, Other}
    end.
	    

data() ->
    lists:seq(1,500).

From guia_internet@REDACTED  Sat Apr 29 22:41:24 2000
From: guia_internet@REDACTED (Antonio)
Date: Sat, 29 Apr 2000 15:41:24 -0500
Subject: All about South America
Message-ID: <200004292050.PAA06297@dragonfans.com>

If you need information about Peru and South America, visit this page:

http://peruvian.hypermart.net=20


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Antonio Zarate