This document describes the changes made to the Kernel application.

Kernel 2.4.1

Fixed errors and malfunctions

• application_controller could hang if application:stop/1 was called at about the same time as the application terminated.
  Own Id: OTP-3351
  Aux Id: Seq4092

Improvements and new features

• The functions format_error/1, change_header/2 and change_notify/3 have been added to the disk_log module.
  Own Id: OTP-3297
  Aux Id: OTP-3296, OTP-3340
• Further changes have been made in the disk_log module. Proper error handling has been added. Several bugs have been fixed.
  Own Id: OTP-3340
  Aux Id: OTP-3297
• The BIF binary_to_term/1 will now ignore any garbage following the encoded term (as it used to do in versions of OTP before R3). The undocumented BIF erlang:old_binary_to_term/1 (which is now equvivalent to binary_to_term/1) will be removed in a future release.
  Own Id: OTP-3368

Kernel 2.4

Known problems

• If an error occurs when accessing a file, the file process dies, and any further attempts to access the file may cause the caller to hang.
  Own Id: OTP-1400
  Aux Id: OTP-1034
• code:is_loaded/1 doesn't type check its arguments.
  Own Id: OTP-2607
• Using gen_tcp:send on a closed socket causes the process to hang.
  Own Id: OTP-2714
  Aux Id: seq 1122
• If more than 1024 bytes of text (more than 256 in release R4) are pasted into the shell, and this text consists of more than one expression sequence (each ending with a period), text after the first 1024 bytes may be lost.
  Own Id: OTP-3041

Fixed errors and malfunctions

• Deadlock occured in global when two nodes reconnect after a connection failure because both nodes tried to set lock on the other nodes in the system.
  This is now solved by letting only one of the reconneting nodes set the lock.
  Own Id: OTP-3162
• A distributed application was not marked as running when it was started. The error occurred on all nodes but the node where the application was actually started, if the application had the permit-flag set to false at boot loading.
  Own Id: OTP-3184
• gen_tcp:send did return {error,normal} when the connection was closed by the other end of the socket. This is now corrected so that {error, enotconn} or possibly {error, econnreset} is returned.
  Own Id: OTP-3224
  Aux Id: OTP-2954, OTP-3220, Seq 3804
• The functions file:eval/1 and file:path_eval/2 now conform with their documentation when evaluation of an expression fails.
  Own Id: OTP-3254
  Aux Id: OTP-3161

Improvements and new features

• New BIFs have been introduced for spawning a process with a Fun: spawn(Fun), spawn(Node, Fun), and corresponding spawn_link, replacing previous undocumented BIFs with the same names.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-3121
  Aux Id: OTP-3141
• Errors occurring while the .erlang file was executed were previously not reported in any way. Now, the first such error is reported using the error logger.
  Own Id: OTP-3161
  Aux Id: OTP-3254
• The option backtrace to process_info/2 returns the stack backtrace of a process, as a binary (use binary_to_list to expand it into a string).
  Own Id: OTP-3180
  Aux Id: Seq 3600
• All kind of trace messages can now be sent to a port instead of to a process (for less performance impact). The erlang:trace/3 BIF now accept an option to set the tracer process or port. The seq_trace:set_system_tracer/1 (for sequential tracing) function now accepts a port identifier as well as a pid.

  There are suitable drivers that can receive trace output in the new runtime_tools application.
  Own Id: OTP-3236

• In order to support the new call tracing, several incompatible changes have been made to the trace/3 BIF.

  The trace/3 BIF is now longer auto-imported; it must be called as erlang:trace/3 or imported.

  The 'bifs' flag is no longer supported. Bifs can be traced as any exported function using the new call tracing (see erlang:trace_pattern/2).

  The 'suspend' flag is no longer supported. Use the new erlang:suspend_process/1 and erlang:resume_process/1 Bifs instead.

  The 'call' flag turns on new call tracing for a process. Use the 'old_call_trace' to turn on the old-fashioned call tracing.

  There is no longer a restriction that process cannot trace a process that is tracing another processs. Therefore, it is possible to construct a circle of processes that are tracing each other (which is a bad idea beacuase the Erlang machine will probably crasch).

  The trace messages from send and receive traces have been changed to make consistent with the other trace messages. Now all trace messages have the pid of the traced process in position 2 and the type of trace in position 3.

  If timestamps are enabled, the first element of each trace message tuple will be 'trace_ts'.

  The return value is no longer 'true', but the number of processes that matched the process argument. For instance, the return value will be '1' if an explicit Pid argument was given.
  (*** INCOMPATIBILITY with R5B01 ***)
  Own Id: OTP-3237
  Aux Id: OTP-3238

• A new kind of call tracing has been added. The new call tracing only support tracing of external function calls, but there is no need to trace-compile the modules to be traced.

  The erlang:trace/3 has been changed and extended to support the new call tracing. It is also possible to set the default tracer and trace flags for all new processes that are or created. There is also a new option to explicitly pass the pid of the tracer process. Also, trace messages can be sent to a port for less performance impact.

  There are two new Bifs: erlang:trace_pattern/2 to enable tracing on certain conditions for one or more exported functions or Bifs, erlang:trace_info/2 to retrieve trace information about a process or exported function.
  Own Id: OTP-3238
  Aux Id: OTP-3237

• EXIT codes now contains more information about where the error occured. There used to be only an indication of the current function; now the complete call chain is included in the EXIT code.

  There are two new Bifs similar to exit/1, except that they generate information about which in function the fault occurred. The Bifs are erlang:fault/1 and erlang:fault/2.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-3239

• The disk_log module has been improved. The new notification {blocked_log, Items} is generated when any of the functions alog/2, balog/2, alog_terms/2, or balog_terms/2 is used with a log that is blocked but not queuing. The new notification {format_external, Items} is generated when alog/2 or alog_terms/2 is used with an internal log. The new function info/1 returns information about a disk log. The functions reopen/2,3, breopen/3, truncate/1,2 and btruncate/2 can be used with wrap logs. Several bugs have been fixed.
  Own Id: OTP-3296
  Aux Id: OTP-3297, OTP-3308
• The disk_log module has been changed according to the following. Requests to close a disk log are always granted. The disk log is unblocked if the blocking process closes the disk log. Any other process just closes the log. If a process that is linked to a disk log terminates, this is handled exactly as if the process had closed the log and then terminated. If any other process than the blocking one tries to unblock a log, {error, {not_blocked_by_pid, Name}} is returned. The exit messages returned by open and reopen have been changed.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-3307
  Aux Id: OTP-3308
• The disk_log module has been slightly changed according to the following. inc_wrap_file/1 sends wrap notices. inc_wrap_file/1 and change_size/2 return an error message if anything goes wrong, rather than terminating the log. block/1,2, sync/1 and truncate no longer queue requests if the log is blocked with QueueLogRecords set to false. Files other than internal logs and shorter than 8 bytes are not overwritten when opening an internal log. If the process that has blocked a log tries to update the log, an error message is returned.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-3308
  Aux Id: OTP-3296, OTP-3307

Kernel 2.2.1

Known problems

• If an error occurs when accessing a file, the file process dies, and any further attempts to access the file may cause the caller to hang.
  Own Id: OTP-1400
  Aux Id: OTP-1034
• Using gen_tcp:send on a closed socket causes the process to hang.
  Own Id: OTP-2714
  Aux Id: seq 1122
• If more than 1024 bytes of text (more than 256 in release R4) are pasted into the shell, and this text consists of more than one expression sequence (each ending with a period), text after the first 1024 bytes may be lost.
  Own Id: OTP-3041

Fixed errors and malfunctions

• global locks do now keep track of all pids that share the same lock, i.e after two set_lock and one del_lock the lock is still set.
  Own Id: OTP-1849
• Global may have exited if bursty nodeup/nodedowns was received to a node. This is solved now.
  Own Id: OTP-2766
  Aux Id: otp-2728, otp-2928
• Changes of the kernel configuration parameter 'distributed' are now taken care of at release upgrade. Kernel will however not automatically move applications to the nodes with highest priority; this must be done manually after the release upgrade is finished (use application:takeover/2).
  Own Id: OTP-2830
• If a transient application exited with reason normal application_controller crashed; this malfunction is now corrected.
  Own Id: OTP-2955
  Aux Id: seq1445
• If a system is started and a permanent application has erroneous environment parameters, the system should crash. This is the behaviour now, before the system only printed an error report. The system will only crash if the application is started from a boot script genrated by calling systools:make_script/1/2 If application:start/1/2 is called the behaviour is as before.
  Note: affects the result of the systools:make_script/1/2. systools:make_script generates now a call to application:start_boot/2 instead of as prevoiusly a call to application:start/2.
  Own Id: OTP-3002
• applicaition:get_application(module_name) returned 'undefined' if the module_name was defined as {module_name, Vsn} in the .app-file
  Own Id: OTP-3081
  Aux Id: Seq 1618
• The possible InternalStatus stopping was missing in the documentation for init:get_status/0.
  Own Id: OTP-3096
  Aux Id: Seq 1672
• when opening an externally formatted disk log the header was not written to the files.
  Own Id: OTP-3118
• application:permit can now handle also applications which are only loaded (but not started).
  Own Id: OTP-3119
• When reading a wrap log and for some reason a file was missing an error was given and it was not possible to read further. Now a missing file will result only in an error log message and it is possible to continue reading the log.
  Own Id: OTP-3136
  Aux Id: OTP-3137
• It is now possible to open an existing wrap log without giving the size parameter. The last given values will be used as default values.
  Own Id: OTP-3147

Improvements and new features

• It is now possible to change the size of an open disk log. For a halt log it is always possible to increase the size, but it is not possible to decrease the size to be less than the current size of the file. For a wrap log it is always possible to increase both the size and number of files. If the max files is decreased the redundant files will be removed next time the log wraps. If the size of the files is decreased the change will not affect the logs already full. If the log size is decreased for instance to save space, the function inc_wrap_log/1 can be used to force the log to wrap.
  Own Id: OTP-2999
  Aux Id: OTP-2989,OTP-2990,seq 1499
• It is possible to force the disk_log to change to next wrap log file by calling the new function disk_log:inc_wrap_log(Log). This makes the current file to be closed and the next index file is opened.
  Own Id: OTP-3078
  Aux Id: Seq 1607
• The undocumented and not recommended BIFs erlang:spawn/2 and erlang:spawn_link/2 will disappear in OTP R6, to be replaced with a more consistent set of BIFs for spawning processes from funs.
  Own Id: OTP-3141
  Aux Id: OTP-3121

Kernel 2.2

• If an error occurs when accessing a file, the file process dies, and any further attempts to access the file may cause the caller to hang.
  Own Id: OTP-1400
  Aux Id: OTP-1034
• code:is_loaded/1 doesn't type check its arguments.
  Own Id: OTP-2607
• If more than 1024 bytes of text (more than 256 in release R4) are pasted into the shell, and this text consists of more than one expression sequence (each ending with a period), text after the first 1024 bytes may be lost.
  Own Id: OTP-3041

Fixed errors and malfunctions

• net_adm:names did not always return the correct result when epmd on the own host was called on Windows or Linux. This is now corrected.
  Own Id: OTP-2851
  Aux Id: OTP-2840
• Some BIFs e.g append could during certain circumstances consume huge amounts of memory (causing the Erlang node to crash) before the garbage collector was invoked to free the unused memory. This is now corrected.
  Own Id: OTP-2865
  Aux Id: Seq 1337
• When a heart command is set with heart:set_cmd(Command) the length is miscalculated which results in 2 garbage characters at the end of the command. This can cause the heart command to fail if the garbage characters are other chars then SPACE or NULL. This is now corrected.
  Own Id: OTP-2903
  Aux Id: Seq 1372
• I thought I already had written the release note for thisx
  Own Id: OTP-2911
  Aux Id: Seq 1384
• Previously gen_tcp:accept erroneously could return {error,normal}. This is now corrected.
  Own Id: OTP-2954
  Aux Id: Seq 1374, OTP-2904
• A request to start a distributed application, which already was started, caused that the application controller hanged. This malfunction is now corrected.
  Own Id: OTP-2967
  Aux Id: Seq 1474
• Two processes starting the same application on the same node at the same time actually started the application twice.
  Now the systems keeps track of all the start requests and starts the application only once. The result of the start is returned to all requesters.
  Own Id: OTP-2973
  Aux Id: Seq 1461
• A local application would not start when its permission was set to true if it was initially started with permission set to false.
  Own Id: OTP-2974
• The error returns from the functions in the rpc module were not consistent: if {badrpc, {'EXIT', Reason}} was reported for remote nodes, only {badrpc, Reason} was reported for the local node. Now, {badrpc, {'EXIT', Reason}} is reported in both cases.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-3007
  Aux Id: OTP-2875
• net_adm:localhost/0 is corrected to not append a "." to the hostname if the domain is not set (i.e when the domain is the empty string).
  Own Id: OTP-3013
  Aux Id: Seq 1533
• On Unix, if there were no current working directory for an Erlang node (if another Unix process has deleted the directory), the commands c:pwd/0, m/0, and m/1 would crasch. The pwd has been corrected to print "Cannot determine current directory" if there are no current directory, and the other commands do not attempt to convert absolute pathnames to relative pathnames as they usually do.
  Own Id: OTP-3015
  Aux Id: Seq 1537
• When starting the emulator with the -noshell switch, a "^R" marker was printed if reading and writing on the console was mixed. This marker is no longer printed.
  Own Id: OTP-3085
  Aux Id: Seq 1629

Improvements and new features

• Functions have been added to the file module to handle links. The read_link_info/1 reads information about a symbolic link, and the read_link/1 function returns what a symbolic link is actually pointing to. The make_link function creates a new hard link, and the make_symlink function creates a new symbolic link.
  Own Id: OTP-1385
  Aux Id: OTP-3008
• It is now possible to reconfigure global groups. The parameter name is changed from node_groups to global_groups.
  Own Id: OTP-2497
  Aux Id: OTP-1559
• gen_udp:recv/3 has been added, in analogy with gen_tcp:recv/3, and gen_udp:recv/[2,3] are now documented.
  Own Id: OTP-2645
• Allowed number of files in a wrap log is increased from 255 to 65000.
  Own Id: OTP-2748
  Aux Id: seq 1204
• gen_tcp:connect/[3,4] take the same options as gen_udp:open/[1,2], in particular the binary option. This is not new in R5, but was left out of the documentation.
  Own Id: OTP-2814
  Aux Id: Seq 1250
• The syntax of Erlang tokens has been extended to allow the use of the full ISO-8859-1 (Latin-1) character set. This is noticeable in the following ways: all the Latin-1 printable characters can be used and are shown without the escape backslash convention; atoms and variables can use all Latin-1 letters.
  Own Id: OTP-2985
• The disk_log wrote a header every time a log file was opened, now the header is only written once in each file.
  Own Id: OTP-3014
  Aux Id: Seq 1534
• A new open mode, append, has been added to the file:open/2 function.
  Own Id: OTP-3067

Kernel 2.1.1

Fixed errors and malfunctions

• ets:file2tab which uses disk_log now uses the read_only option to disk_log:open when it opens the file.
  Own Id: OTP-1716
  Aux Id: OTP-1765
• All applications are now informed of all changed, new and removed configuration parameters at installation of a new release. The new call-back functions is defined as Mod:config_changed(Changed, New, Removed). Where Mod is the module defined in the .app file. Refer to the reference manual application(3).
  Own Id: OTP-2012
• When killing a shell in the ^G command level using the sequence "^G k", some processes associated with the shell were left running. Now, there are no extra processes left anymore.
  Own Id: OTP-2317
• The function gen_tcp:controlling_process(S, NewOwner) did hang the calling process if it was not the current owner of S. This is now corrected. If called by any other process than the current owner {error, eperm} will be returned.
  Own Id: OTP-2321
  Aux Id: seq 779
• When application environment variables are given on the command line, no error message was given if the variable's value was malformed; application:get_env/2 simply returned 'undefined'. Now, application:start/1 returns an error in those cases.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-2350
  Aux Id: OTP-2347, OTP-2348
• If a process attempts to call erl_ddll:unload_driver/1 on a driver for which it didn't previously call erl_ddll:load_driver/2, the unloading fails. In previous release, either the result 'ok' was returned, or in certain cases the erl_ddll server crashed. Now the correct error tuple is returned.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-2568
• Sometimes when a R3 node and a R4 node were connected, global could crash due to not checked '{badrpc,nodedown}' messages. This is now corrected.
  Own Id: OTP-2648
  Aux Id: Seq 987
• The processes which controls a port corresponding to a socket is now set to priority high instead of normal to assure that e.g node-ticks between distributed nodes are sent fast enough.
  Own Id: OTP-2709

Improvements and new features

• The documentation has been augmented with a description of the error return values from erl_ddll:load_driver/2 and erl_ddll:unload_driver/1, and the error formatting function format_error/1.
  Own Id: OTP-2569
• The 'backlog' option to gen_tcp:listen/2 is now documented.
  Own Id: OTP-2674

Kernel 2.1

Fixed errors and malfunctions

• For the arguments to the command-line option -s, the documentation was incorrect. It has been changed to reflect the actual behaviour, namely that all arguments to the function called by -s are passed as atoms.
  Own Id: OTP-2087
• When using the -boot and -config command-line options on Windows, filenames in the native Windows syntax using only backslashes didn't work -- forward slashes had to be used. Now backslashes work as well as forward slashes.
  Own Id: OTP-2373
• An unnecessary report to the error logger caused by a timeout from inet:gethostbyname and inet:gethostbyaddr is removed.
  Own Id: OTP-2478

Improvements and new features

• New start type, {failover, node()}, added. Note, for compability reasons this is only valid if the new key start_phases is defined in the .app-file for the application, refer to application (3). It is also possible to check the current start type by application:start_type(), refer to application (3)
  Own Id: OTP-1504
  Aux Id: OTP-1979, OTP-2498
• A first increment to allow several global name spaces to exist in the same system. The Global Groups are defined in the .config file by the key '{node_groups, [{GroupName, [Node]}]}. If the node_groups-key is not defined the system behaves as before; if the Global Group service is used then it is required that all nodes in a system are defined in one. and only one, Global Group. It is not possible to mix nodes belonging to a global group and nodes not belonging to a global group in the same system, if global group functionality is used.
  Missing functionality: Reconfiguration, at the moment it is not possible to change the configuration without restarting all nodes.
  Own Id: OTP-1559
  Aux Id: OTP-2497
• Better error messages for erroneous .config file.
  Own Id: OTP-1983
• The functions write_file_info/2, change_owner/2,3, and change_time/2,3 in the file module are now documented.
  Own Id: OTP-2252
  Aux Id: seq 710
• It is now possible to synchronize the start of an application by defining a new key in the .app file, {start-phases, [{Phase, Args}]}. This will result that the new call back function Mod:start_phase(Phase, Args) is called, Mod is the module defined in the mod key of the application. There is also a generic help module to syncronize the start of included applications, application_starter. If this module is defined in the mod key for the top application, the included applications will be started in each start phase in the order of appearance in the included_applications key.
  Own Id: OTP-2498
  Aux Id: OTP-1504
• It is added to the documentation of file:list_dir/1 that the returned filenames are not sorted.
  Own Id: OTP-2508
  Aux Id: seq 891
• A new key, id, in the application resource file (.app, ). It can be used to define the product identification of the application.
  Own Id: OTP-2518
• The description of error_handler:undefined_global_name/2 has been removed, since it's no longer called from Erlang 4.6 and later.
  Own Id: OTP-2525
• Sequential tracing is available in alfa status and only for JAM systems. Since it is an alpha release the programmatic interface could be slightly changed based on experience from users. The module seq_trace contains the interface. Sequential tracing makes it possible to trace all messages that are a direct result from one initiating message e.g. all messages in a call-setup for one connection.
  Own Id: OTP-2527
• It is now possible to read an application's resource file (.app) keys. New functions: application:get_all_key() application:get_all_key(Application) application:get_key() application:get_key(Application, Key)
  Own Id: OTP-2535

R3B02 (Kernel 2.0.5)

Fixed errors and malfunctions

• The description of the options resuaddr and keepalive in inet:setopts/2 has been corrected.
  Own Id: OTP-2223
  Aux Id: seq 679
• The reference manual for the kernel application is corrected regarding the boot_server_slaves variable. The value should be a list of slave IP-addresses and not a list of nodenames as stated earlier.
  Own Id: OTP-2224
  Aux Id: seq 680
• application:permit(App, false) may hang during certain circumstances. This is corrected.
  Own Id: OTP-2231
  Aux Id: seq699 HA72879
• The Erlang system did always contact the DNS server (if configured) on startup and this could cause the system to hang. This is now corrected.
  Own Id: OTP-2308
  Aux Id: seq 765
• dist_ac could hang forever if a nodedown was received at certain times.
  Own Id: OTP-2368
  Aux Id: seq813

R3B01 (Kernel 2.0.4)

Fixed errors and malfunctions

• The -pa and -pz options to erl did not add the paths to the code server when combined with the -mode embedded option. This is corrected.
  Own Id: OTP-2160
  Aux Id: seq 644

R3B (Kernel 2.0.3)

Fixed errors and malfunctions

• The file:sync/1 used to crash the process for the file it was used on; this has been corrected.
  Own Id: OTP-1778
  Aux Id: seq379
• os:cmd/1 used to hang if given a command containing a shell comment character, for example: os:cmd("ls #"). This has been corrected.
  Own Id: OTP-1805
  Aux Id: seq 385
• The 'EXIT' reason reported from the BIF process_info/1 is corrected; it now reports 'badarg' when the argument is not a pid.
  Own Id: OTP-1874
• The documention for erlang:register/2 has been reworded to clarify that a registered name can be used by the send operation, rather than generally.
  Own Id: OTP-1875
• The call to erl_ddll:unload_driver for a statically linked in driver now returns {error,linked_in_driver}. Previously the incorrect result {error, not_loaded} was returned.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-1962
• global:(un)register_name is changed to set lock only on the nodes known to the global_name_server.
  Own Id: OTP-2011
• When the pg2 server is started and a new disk log is opened, the call to disk_log:open used to crash. This has been corrected.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-2028
• A more informative error messages is displayed if you try to start an Erlang node with the same name as an existing. The message in R3A was cryptic.
  Own Id: OTP-2032
  Aux Id: seq 534
• The reference manuals for modules gen_tcp, gen_udp and inet are corrected.
  Own Id: OTP-2034
  Aux Id: seq 527
• When loading of a module fails (for instance, because of a corrupted file), the code server will print an error report which includes the name of the file. The error messages printed by the binary loader are still printed, however. In a future version, there will be ONE message printed, and it will be more informative.
  Own Id: OTP-2049
  Aux Id: seq 546
• In UNIX when the resolver file (typically /etc/resolv.conf) is not found, this is not treated as an error any more. A warning is issued and this type of warning is disabled as default. The warning messages can be turned on with the kernel environment variable inet_warnings = on.
  Own Id: OTP-2053
  Aux Id: seq 552
• The communication between distributed Erlang nodes could hang if one of the nodes suddenly dies. The cause was incomplete error handling in the inet_* modules and the inet-driver. This is corrected.
  Own Id: OTP-2055
  Aux Id: seq 549
• There was a problem (in R3A) on Windows NT , that it was impossible to make contact between two Erlang nodes on the same machine if the machine was not configured to use DNS and did also not have it's own hostname in a lmhosts file. This is corrected.
  Own Id: OTP-2061
  Aux Id: seq 572, seq 573
• The documentation has been updated to cover VxWorks too.
  Own Id: OTP-2157

Improvements and new features

• The documentation for erlang:process_info(Pid, status) now lists the suspended state as a possible return value.
  Own Id: OTP-2105
  Aux Id: seq 601
• The timeouts for heart are now configurable. The environment variable HEART_BEAT_TIMEOUT can be used to set the maximum time that heart accept without getting any heart beat message from the Erlang node. Another variable HEART_BEAT_BOOT_DELAY can be used to set the delay time before the hardware watchdog (if any) is triggered. This is used to reserve time for closing down the system in a proper way without interference from the watchdog. Both variables can have values in seconds and must be in the range 10 < x <= 65535. If the variable(s) are not set the default value is 60 seconds for both timeouts.
  Own Id: OTP-2143
• It is now possible to tell the Erlang node to try with dns even if ONLY nis or nis+ and not dns is specified in the /etc/nsswitch.conf file. This can be activated with the kernel valiable inet_dns_when_nis set to true. The variable can be set in the start script or on the command line like this: erl -kernel inet_dns_when_nis true.
  Own Id: OTP-2153

R3A02

Fixed errors and malfunctions

• The erlang distribution did not work if the search entry in /etc/resolv.conf was missing. This is corrected.
  Own Id: OTP-2036
  Aux Id: seq 542
• The required format of domain and hostnames is relaxed. Now the requirement is that the name only consists of visible characters (16#21..16#7E).
  Own Id: OTP-2037
  Aux Id: seq 543

R3A (Kernel 2.0)

Fixed errors and malfunctions

• An application can be loaded even if it includes another application which is not yet loaded.
  Own Id: OTP-1586
• Now the tty is reset correctly when leaving Erlang.
  Own Id: OTP-1654
• disk_log always truncated internal wrap logs; this is corrected.
  Own Id: OTP-1869
• The call to pg2:get_closest_pid exited if the process group has no members. This is corrected.
  (*** POTENTIAL INCOMPATIBILITY ***)
  Own Id: OTP-1945

Improvements and new features

• Start of applications is now more asynchronous, in order to prevent deadlock if a starting application calls application:start and which_applications.
  Own Id: OTP-1629
• The application_controller now uses less memory for the storage of application specifications
  Own Id: OTP-1630
• The documentation about how to start distributed applications is improved.
  Own Id: OTP-1631
• Improvements in the disk_log module: Log name is printed from the info function. A Pid is deleted from log owners when the Pid dies or calls close. Reconfiguration of logs is now handled correctly.
  Own Id: OTP-1634
  Aux Id: OTP-1435
• The application_controller is split into two processes; one that handles local applications and one that handles the distributed applications. If distributed applications are used, the configuration parameter start_dist_ac should be set.
  Own Id: OTP-1636
• The new functions pwrite and pread are added to the file module. These functions makes read and write on a specific position in a file more efficient.
  Own Id: OTP-1640
• The syntax of different files defined by Kernel is described in separate documents. Se the reference manual for app(4) and config(4).
  Own Id: OTP-2149

Known problems

• It is currently not possible to open a disk_log for reading only. The same limitation applies to ets:file2tab. We consider this to be a bug which will be fixed in a forthcoming version.
  Own Id: OTP-1716

1 Kernel 1.3.2

1.1 Fixed Bugs and malfunctions

• file:stop does not hang any more.
  Own Id:OTP-1404
  
• net_kernel could in some situations send two nodeup messages to the monitor processes (processes that have evaluated net_kernel:monitor_nodes()).
  This problem could make global hang when several nodes connected.
  Own Id:OTP-1418; OTP-1127, OTP-1412
  Aux Id:tir-d-088
  
• net_kernel did not send nodedown messages for allowed nodes. If net_kernel:allow(Nodes) was used, no nodedown messages at all were sent to monitor processes net_kernel.
  nodedown messages are now sent for allowed nodes but are ignored for connection attempts from disallowed nodes.
  Own Id:OTP-1419
  
• application_controller had sync problems in the takeover phase when an application was remote started.
  Own Id:OTP-1426
  
• application_controller did sometimes report {error,{not_started,App}} even though the application in question has been started on another node.
  Own Id:OTP-1454
  Aux Id:HA52440
  
• application_controller could hang due to a deadlock situation during startup in a distributed system.
  Own Id:OTP-1472
  

1.2 Improvements and new features

• The support for dynamic loading of drivers in module erl_ddll is enhanced with reference counting of loaded drivers and automatic unloading of drivers when the "owner" process terminates.
  Own Id:OTP-1460
  
• The os module has got 2 new functions getenv/1 to read environment variables from the hos operating system and find_executable/1,2 to find executable programs using a search path.
  Own Id:OTP-1461
  
• A new function application:which_application(Module) which returns the application that Module belongs to.
  Own Id:OTP-1008
  

2 Kernel 1.3.1

2.1 Fixed Bugs and malfunctions

• Malformed string/list as argument to unix:cmd/1 caused entire ERTS to crash.
  Own Id: OTP-1384
  
• It was not possible to convert a non distributed system into a distributed system as stated in the net_kernel reference manual. Note that this is not the recommended way to start a distributed system.
  Own Id: OTP-1393
  
• net_adm:world/1 was broken on Windows NT, since it relied on unix:cmd/1.
  Own Id: OTP-1397
  
• The disk_log_server now clears it's state correctly when a disk_log process terminates.
  Own Id: OTP-1402
  

3 Kernel 1.3

3.1 Improvements and new features

• net_ticktime is configurable through the kernel application. net_ticktime specifies the time within which a non responding node will be considered to be down.
  
• -boot_var flag read by init. This flag is used to set a path variable in the boot script. If applications will be placed under another directory than $ROOT/lib in an embedded system this flag can be used.
  
• A new function for controlling execution of applications is added; application:permit/2. The function controls which applications are permitted to execute on the node.
  
• A new configuration parameter permissions specifies the default permission an application has when it is loaded.
  
• New functions in application.
  application:load(App, Dist) - set (and check!) distribution configuration for an application at load time.
  application:get_application/0,1 - get the application of a pid.
  Own Id: OTP-1306
  
• .config files are now allowed to contain comments.
  Own Id: OTP-1134
  Aux Id: HA37561
  
• It is now possible to specify more than one configuration file to erl, by using the command line flag -config.
  
• The code server (module code) did sometimes store relative pathnames which could cause troubles in some cases. The code server is changed to always store absolute pathnames.
  Own Id: OTP-1239
  Aux Id: erlang/66
  
• An elucidation regarding strings in the code module. Since the 1.1 version of the kernel application the code module always returns directory (and file) names as strings. See the code(3) manual page.
  It is preferable that directory names are provided as strings to all functions. The possibility to provide directory names as atoms may be removed in future releases. Module names should always be given as atoms and the possibility to provide module names as strings may be removed in future releases.
  Own Id: OTP-1186
  
• code:priv_dir/1 was very slow and is made much faster now.
  Own Id: OTP-1339
  
• The module disk_log is moved from stdlib to kernel, and some new functionality is added. disk_log supports wrap and halt logs, the size of a log is configurable, it supports different file formats, and it supports replicated logs.
  Own Id: OTP-1305
  
• The erl_boot_server is dynamically configurable.
  Own Id: OTP-1275
  
• The functions add_slave/1, delete_slave/1 and which_slaves/0 are added to the erl_boot_server.
  
• New option raw to file:open and also a new variant of the function which takes a list of options. The open with an optionlist is the recommended way to open a file from no on.
  Own Id: OTP-1242
  
• New format for the Reason field when {error,Reason} is returned from functions in the file module. There is also new documentation about this in the reference manual.
  Own Id: OTP-1075
  
• The configuration parameter os is removed from kernel.app. The function os:type() is used instead.
  Own Id: OTP-1277
  

3.2 Fixed Bugs and malfunctions

• net_adm:world() is corrected on Windows NT.
  Own Id: OTP-1219
  
• file:list_dir("c:") returns "No such file..." on NT
  Own Id:OTP-1237
  
• Bad call to c:c/1 did crash the Erlang shell. Solved by addition of a better test that a module name is correct.
  Own Id: OTP-1256
  Aux Id: erlang/73
  
• The rpc:cast function was synchronous when casted function call was performed at the current node.
  Own Id: OTP-1292
  

3.3 Incompatibilities with Kernel 1.1.1

• New format for the Reason field when {error,Reason} is returned from functions in the file module. This is an interface change (the format of Reason but it will only break a minimal amount (if any) of old code since the previous format of Reason was more or less useless in match operations. There where also errors in the documentation and other inconsistencies with the old format.
  The most likely places where old code needs to be adjusted is where the highlevel functions consult, path_consult, eval and path_eval in combination with a match for the result {error,open} is used.
  Own Id: OTP-1075
  

3.4 Known bugs and problems

-

4 Kernel 1.1.1

4.1 Improvements and new feature

-

4.2 Fixed Bugs and malfunctions

• application:get_env/1 returned undefined for all parameters during startup of an application.
  Own Id: OTP-1079
  
• When synchronization of mandatory node fails using the sync_nodes_mandatory configuration parameter , the node should be takendown, but it wasn't.
  Own Id: OTP-1083
  
• Manual page for file corrected.
  Own Id: OTP-1102
  
• Attempt to start an application when already running causes error. Now application:start/1,2 returns {error,{already_started,Name}} if the application is running.
  Own Id: OTP-1111
  Aux Id: tir-f-087, tir-d-087
  
• Restart (init:restart/0) of system did not work after a software upgrade. Started using the now old version.
  Own Id: OTP-1113
  Aux Id: HA37170
  
• init:stop/0 did not work after a restart (init:restart/0).
  Own Id: OTP-1117
  

4.3 Incompatibilities with Kernel 1.1

-

4.4 Known bugs and problems

-

5 Kernel 1.1

5.1 Improvements and new feature

• Application configuration paramaters can be given from the command line (overrides the configuration file):
  

  erl -Appl Key Value

• Load applications before start. All applications (included in the boot script) are loaded before the first application is started.
  
• Heart uses the hardware watchdog (Solaris), see heart(3).
  
• Added error_logger:info_msg/1,2.
  
• Support for distributed applications enhanced and documented.
  

5.2 Fixed Bugs and malfunctions

• net_adm:ping(Node) will never return pong if this node is not allowed (net_kernel:allow/1) to connect to Node.
  
• net_kernel:allow/1 handles hidden nodes.
  

5.3 Incompatibilities with OTP P1G

• A configuration file must have suffix .config. (For example, to use the file sys.config, erl -config ./sys is used)
  
• Old boot scripts won't work - generate new with systools.
  
• Added the application behaviour. Change in .app file: previously, {start, {M, F, A}} was specified, now {mod, {M, A}} should be specified, and M:start(Type, A) is called.
  
• code:root_dir/0, code:lib_dir/0, code:compiler_dir/0 and code:uc_dir/0 returns a string.
  
• The error_handler is silent, e.g. it will not write ** cannot autoload: Mod ** and ** undefined registered name: Name ** to stdout any longer.
  

5.4 Known bugs and problems

-