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<h1>1 Highlights</h1>
<p>This document lists some highlights of Erlang 5.7/OTP R13A
(unpatched), compared to the previous version Erlang 5.6/OTP R12B,
with focus on things not already released as R12B patches.</p>
<p>Note: This document was compiled at the time when R13A was released
and does not list any features introduced in R13 patches.</p>
<h3><a name="id2256102">1.1
Erlang Language and Run-time System</a></h3>
<h4>Multi-core and SMP performance improvements</h4>
<p>
There SMP performance is significantly improved and will
allow most applications to scale much better on systems with many
cores or processors. Listed below are some of the most important improvements:
</p>
<ul>
<li>
<p>
The runtime system with SMP support now uses <strong>multiple,
scheduler specific run queues</strong>, instead of one globally shared
run queue.
</p>
<p>
The lock protecting the shared run queue was heavily
contended, and the shared run queue also caused Erlang
processes to randomly migrate between schedulers with
negative cache effects as a result.
</p>
<p>
With the current scheduler specific run queue solution, lock
contention due to run queue protection has been reduced, and
Erlang processes are only migrated when needed to balance the
load between the schedulers. The reduced amount of migration
also reduce lock contention on locks protecting the scheduler
specific instances of the erts internal memory allocators.
</p>
<p>
The scheduler specific run queues are also a necessity for a
lot of future planned NUMA (Non-Uniform Memory Access)
specific optimizations.
</p>
</li>
<li>
<p>
Message passing has been further optimized for parallell execution.
This makes parallell sending to one common receiver much more efficient.
</p>
</li>
<li>
<p>
Scheduler threads can now be bound to logical processors on newer
Linux ans Solaris systems.
</p>
</li>
</ul>
<h4>Unicode support</h4>
<p>
Support for Unicode is implemented as described in EEP10.
Formatting and reading of unicode data both from terminals
and files is supported by the <span class="code">io</span> and <span class="code">io_lib</span> modules.
Files
can be opened in modes with automatic translation to and from
different unicode formats. The module 'unicode' contains
functions for conversion between external and internal
unicode formats and the re module has support for unicode
data. There is also language syntax for specifying string and
character data beyond the ISO-latin-1 range.
</p>
<h4>New BIF's</h4>
<p>
The BIFs <span class="code">atom_to_binary/2</span>, <span class="code">binary_to_atom/2</span> and
<span class="code">binary_to_existing_atom/2</span> have been added.
</p>
<h4>Independent Erlang clusters on the same host</h4>
<p>
Nodes belonging to different independent clusters can now
co-exist on the same host with the help of a new
environment variable setting <span class="code">ERL_EPMD_PORT</span>.
The environment variable is used by Erl_interface and J_interface
as well.
</p>
<h3><a name="id2254159">1.2
New Applications</a></h3>
<h4>Reltool</h4>
<p>
Reltool is a release management tool.
It analyses a given Erlang/OTP installation and determines
various dependencies between applications.
The graphical frontend depicts the dependencies and enables
interactive customization of a target system.
The backend provides a batch interface for generation of
customized target systems.
The application is still somewhat limited and should be regarded
as experimental in this release. The intention is that this
application will be a valuable tool for making both traditional
Erlang target systems as well as standalone components in Erlang.
</p>
<h4>WxErlang</h4>
<p>
wxErlang is an Erlang binding to the WxWidgets GUI library which
provides support for cross platform GUI applications.
wxErlang is still in beta status and the intention is that it shall
replace GS in a later stage. The Erlang debugger is also shipped in
a wxErlang version.
</p>
<h3><a name="id2254202">1.3
New features in Existing Applications</a></h3>
<h4>Common_test</h4>
<p>
A support client module for SSH and SFTP, <span class="code">ct_ssh</span>, has
been introduced.
</p>
<p>
Test case groups have been introduced. With this feature
it's possible to execute groups (possibly nested)
of test cases.
</p>
<p>
A group definition contains a name tag, a list of
properties and a list of test cases (including possible
nested group definitions). The properties make it possible
to execute test cases in parallel, in sequence and in
shuffled order. It is also possible to repeat test cases
according to different criteria.
</p>
<h4>Dialyzer</h4>
<p>
The analysis now accepts <strong>opaque type declarations</strong> and
detects
violations of opaqueness of terms of such types. Starting
with R13, many Erlang/OTP standard libraries (array, dict,
digraph, ets, gb_sets, gb_trees, queue, and sets) contain
opaque type declarations of their main data types. Dialyzer
will spit out warnings in code that explicitly depends on the
structure of these terms.
</p>
<p>
Added support for handling UTF segments in bitstreams and for
detecting obvious type errors in these segments. Warning:
This code is not terribly tested though since there are very
few Erlang programs which use Unicode-based binaries - not
surprising since this is a new language feature of R13.
</p>
<p>
Strengthened the discrepancy identification when testing for
equality and matching between terms of different types. This
detects more bugs in code.
</p>
<p>
See the Dialyzer documentation and release notes for even more
enhancements.
</p>
<h4>SSL</h4>
<p>
The "new_ssl" implementation is significantly improved and should be
near product status now.
The new SSL is implemented in pure Erlang except for
the crypto routines that are implemented in the crypto driver which
is an interface to libcrypto from OpenSSL.
</p>
<h4>STDLIB</h4>
<p>The Erlang scanner has been augmented as to return white-space,
comments and exact location of tokens.
This means that the scanner can easily be used in tools such as editors,
pretty printers, syntax highlighters etc.
where it is important to be able recreate the original source document.
</p>
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