Highlights
Erlang 5.1/OTP R8B

This document describes the major new features and changes that will be introduced in the next Erlang/OTP version R8B which will be released the 17:th of October 2001.

The major focus in the development of this version has been:

· Improved characteristics for huge systems and systems with high demands regarding soft real time characteristics. The work here is mainly concentrated on multithreaded I/O, memory handling and improvements in disk and ram based tables and Mnesia.

· Introduce the important new application Megaco/H.248 as part of OTP.

· Introduction of a permuted index in the html version of the documentation as well as a reduction of levels of html pages for each application.

Below follows a brief description of the most significant changes in each application.

Appmon, graphical view of applications and processes

• A web based user interface is added in parallell with the old graphical interface based on GS.

Asn1, compiler and runtime functions for ASN.1

• New option per_bin which makes the encode/decode functions use binaries and the bit syntax instead of lists. The use of binaries will be the default solution in forthcoming versions.
• Now supporting the most common use of Information Objects according to X.681 for both BER and PER (aligned).
• The new option ber_bin which uses binaries in the encode/decode functions is now officially supported. It is recommended to use ber_bin instead of ber, the use of binaries will be the default in forthcoming versions.
• In combination with the BER encoding rules now the DER (Distinguished Encoding Rules) is supported. The DER encoding rules is defined as a number of restrictions to the BER encoding rules and is used mainly by the X.500 directory standards.

For more details, see Release Notes.

Comet, the COM client for Erlang

Various improvements and some new example. One example shows how to access various data sources with ActiveX Data Objects (ADO). For more details see the Release Notes.

Compiler

• Various code optimizations, especially records are handled better.
• Floating point arithmetic is faster.
• A more powerful inliner is added.
• New syntax for setting all remaining fields in a record to the same value. This is useful when creating a wildcard record which e.g is used as input to mnesia:match. The following statement sets field a to Val and all other fields to ’_’:
  #rec{a=Val,_=’_’}
  This is very practical for records with many fields.
• Improved handling of list comprehensions resulting in faster execution.
• New logical operators andalso and orelse.

CosEvent, (a CORBA service)

This version is a completely new version of the cosEvent application; older versions were not compliant with the OMG specification. The "look and feel" has been changed to be more uniform with the other COS-services.

cosFileTransfer NEW (a CORBA service)

An Erlang implementation of the OMG CORBA FileTransfer service.

Note: The OMG CosFileTransfer specification have not been finalized yet. Hence, the API may be changed in the future.

CosNotification (a CORBA service)

Minor changes, see Release Notes.

cosProperty NEW (a CORBA service)

An Erlang implementation of the OMG CORBA Property service.

CosTime (a CORBA service)

Minor changes, see Release Notes.

CosTransactions (a CORBA service)

Minor changes, see Release Notes.

Crypto, MD5, SHA and CBC-DES encryption/decryption

No changes since R7B01.

Debugger

Internal changes.

Erlang emulator (ERTS)

• Improved multithreaded I/O
• Improved inet_driver (IP)
• Named ports
• Improved memory management on Unix (using mmap) gives less memory fragmentation.
• Improved diagnostic BIF's retrieving memory information
• Improved floating point arithmetic
• Support for scatter/gather I/O in the file driver to improve performance.
• Improvements of the file drivers real-time characteristics for the single threaded case (default) when reading/writing very large blocks.

Erl_Interface, a C library for integration of Erlang and C programs

A lot of improvements, the library "ei" now can be used without support from the old library "erl_interface". The "ei" library is reentrant and makes it possible to have i.e. multiple ei-nodes on VxWorks (which means multiple ic generated nodes too). The old “erl_interface” API is still there but only for backward compatibility reasons. The “Erl_interface” API and lib is now obsolete and should not be used in new development.

EVA, event and alarm handling

No changes since R7B01.

GS, the Graphics System

• Some internal modules and processes in GS were prefixed with gtk. This prefix has been changed to gstk not to clash with modules that interface to the graphical toolkit Gtk.

Other minor internal changes, see GS Release Notes.

IC, the IDL compiler and runtime functions

• Added support for erlang::binary in compiler and C backends.
• Multiple backend option for faster compilation. Makes it possible to generate code with several different backends in one compiler run.
• Various bugfixes and optimizations.

Inets, HTTP server and FTP client.

Minor changes, see Release Notes.

Jinterface, a library for integration of Erlang and Java programs

No changes since R7B01.

Kernel, mandatory basic applications

• Erlang nodes can be hidden in which case they don't participate in the global name space and dont appear in the list of nodes returned by the nodes/0 Bif. New Bif's are added to retrieve information about hidden nodes. The distribution mechanisms are also generally improved to meet demands for larger networks of distributed erlang nodes.
• The inet, inet_tcp, inet_udp components are further improved and optimized
• The global name service is faster.

Megaco, a Megaco/H.248 protocol stack NEW

A framework for building applications on top of the Megaco/H.248 protocol.
Megaco/H.248 is a protocol for control of elements in a physically decomposed multimedia gateway, enabling separation of call control from media conversion. A Media Gateway Controller (MGC) controls one or more Media Gateways (MG).

The semantics of the protocol has jointly been defined by two standardization bodies:

• IETF - which calls the protocol Megaco
• ITU - which calls the protocol H.248

Mesh

This application has been removed.

Mnemosyne, database queries

No changes since R7B01.

Mnesia, a DBMS

Already in R7 (Mnesia-3.10)

The implementation for tables with property disc_copies is significantly improved and does not use dets anymore. This will improve over all system performance.

R8 (Mnesia-4.X and later)

The improvements in dets will yield an improvement on the disc_only_copies storage type.

select/[23] is implemented which should decrease the need to use Mnemosyne and match_object. By use of select the search performance is improved. The data returned from a search with select can be taylored by the user. See ERTS User's Guide for syntax of match expressions.

Synced transactions have been implemented, these kind of transactions do not increase the performance but have a better behaviour from a system perspective. A node B cannot be overloaded by running fast transactions on node A and you cannot overload disk_log as you can with the normal mnesia:transaction/[123] call.

Old dependencies, workarounds and support for old Erlang/OTP release will be removed.

Mnesia_Session, interface to Mnesia

Minor internal changes, see Mnesia_Session Release Notes.

ODBC, interface to SQL databases

The application has been rewritten. The main change is that allocation and deallocation om memory is now handled by the application.

ODBC also need handlers for communication with the database. These handlers are now allocated by application.

New interface functions have been added which replace the old ones. The old interface functions are retained for backwards compatibility but may be removed in the future. For more information, see the ODBC Reference Manual.

Orber, the Erlang ORB

The overhead for Inter-ORB communication has been reduced significantly compared with the first R7B version (3.1.8). As a part of this work the memory usage has also been reduced.

OS_Mon, monitoring of disk-usage and OS resources

• The memsup and disksup "supervisors" are improved to give faster responses and generate less overhead.
• Now works on Linux and FreeBSD

Parsetools, a parser generator

No changes since R7B01.

Pman, graphical tool for inspection and tracing of processes

Minor internal changes, see Pman Release Notes.

Runtime_Tools, trace functionality etc.

Tracing is generally improved and bugfixed, see the dbg and erlang manual sections

SASL, release handling, upgrade etc.

• The report browser (rb) no longer ignores faulty events - it prints the raw terms instead. It also presents user-generated error_report and info_report events more nicely.
• systools_make uses Xref instead of Exref for cross reference checks. The format of the warnings for undefined functions has been changed.
  (*** POTENTIAL INCOMPATIBILITY ***)

SNMP, Simple Network Management Protocol

Minor changes, see Release Notes.

SSL, Secure Socket Layer

Minor changes, see Release Notes.

STDLIB, mandatory library functions

ETS/DETS

• Ets and Dets now includes more powerful alternatives to the (d)ets:match/2, (d)ets:match_object/2 and (d)ets:match_delete/2 calls. The new matching alternatives are called (d)ets:select/2 and (d)ets:select_delete/2.
• The new calls (d)ets:match/1, (d)ets:match/3 and corresponding match_object/select calls makes it possible to fetch smaller chunks of matching objects for processing instead of always retrieving all matching objects at the same time
• The predicate (d)ets:member/2 makes it possible to look for a key in an ets table without retrieving the whole object
• (d)ets:insert/2 now also accepts a list of objects to be inserted in one call
• Furthermore the following (d)ets calls are added: delete_object, delete_all_objects, from_(d)ets, to_(d)ets, init_table and test_ms (only ets). See the documentation for details
• Dets is much improved in terms of speed, resource consumption and works better together with multithreaded I/O.

Disk_log

Improved performance, especially when using multithreaded I/O.

Toolbar, graphical launcer

Minor internal changes, see Toolbar Release Notes.

Tools, various useful development tools

· Coast was much too slow and inefficient, especially for large modules. Also, it was discovered that Coast in some cases returned erroneous values.

Consequently, Coast has been discontinued and is replaced with a new tool Cover with similar interface and functionality. Refer to the Tools User's Guide and Reference Manual for more information about Cover. (*** POTENTIAL INCOMPATIBILITY ***)
Added a web based user interface to Cover.

• xref represents unresolved calls with calls where the module, the function or the number of arguments are atoms and integers that are unlikely to occur in an Erlang system. Calls to erlang:apply/2 and the like are included among the external calls. This is in contrast to R7 where calls to apply and spawn were used for representing unresolved calls.
  (*** POTENTIAL INCOMPATIBILITY ***)
• A new profiling tool fprof which measure how time is used in your Erlang programs. Uses trace to file to minimize performance impact, and displays time for calling and called functions.

Other minor changes, see Tools Release Notes.

TV, grapical viewer for ets and mnesia tables

Minor internal changes, see TV Release Notes.

WebTool NEW

A framework for web based tools.