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authorHans Bolinder <[email protected]>2015-03-12 15:35:13 +0100
committerBjörn Gustavsson <[email protected]>2015-03-12 17:42:20 +0100
commit0c20078ff0fbad9066c8dd4ebcd6faa0b4f31b42 (patch)
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Update System Principles
Language cleaned up by the technical writers xsipewe and tmanevik from Combitech. Proofreading and corrections by Hans Bolinder.
-rw-r--r--system/doc/system_principles/create_target.xmlsrc367
-rw-r--r--system/doc/system_principles/error_logging.xml38
-rw-r--r--system/doc/system_principles/system_principles.xml186
-rw-r--r--system/doc/system_principles/upgrade.xml98
-rw-r--r--system/doc/system_principles/versions.xml288
5 files changed, 482 insertions, 495 deletions
diff --git a/system/doc/system_principles/create_target.xmlsrc b/system/doc/system_principles/create_target.xmlsrc
index a8ee2d1245..7c566229ac 100644
--- a/system/doc/system_principles/create_target.xmlsrc
+++ b/system/doc/system_principles/create_target.xmlsrc
@@ -31,55 +31,54 @@
<rev>A</rev>
<file>create_target.xml</file>
</header>
+ <marker id="creating upgrading target system"></marker>
- <section>
- <title>Introduction</title>
- <p>When creating a system using Erlang/OTP, the most simple way is
- to install Erlang/OTP somewhere, install the application specific
+ <p>When creating a system using Erlang/OTP, the simplest way is
+ to install Erlang/OTP somewhere, install the application-specific
code somewhere else, and then start the Erlang runtime system,
- making sure the code path includes the application specific code.</p>
- <p>Often it is not desirable to use an Erlang/OTP system as is. A
- developer may create new Erlang/OTP compliant applications for a
+ making sure the code path includes the application-specific code.</p>
+ <p>It is often not desirable to use an Erlang/OTP system as is. A
+ developer can create new Erlang/OTP-compliant applications for a
particular purpose, and several original Erlang/OTP applications
- may be irrelevant for the purpose in question. Thus, there is a
+ can be irrelevant for the purpose in question. Thus, there is a
need to be able to create a new system based on a given
- Erlang/OTP system, where dispensable applications are removed,
- and a set of new applications are included. Documentation and
+ Erlang/OTP system, where dispensable applications are removed
+ and new applications are included. Documentation and
source code is irrelevant and is therefore not included in the
new system.</p>
- <p>This chapter is about creating such a system, which we call a
+ <p>This chapter is about creating such a system, which is called a
<em>target system</em>.</p>
- <p>In the following sections we consider creating target systems with
- different requirements of functionality:</p>
+ <p>The following sections deal with target systems
+ with different requirements of functionality:</p>
<list type="bulleted">
- <item>a <em>basic target system</em> that can be started by
- calling the ordinary <c>erl</c> script, </item>
- <item>a <em>simple target system</em> where also code
- replacement in run-time can be performed, and</item>
- <item>an <em>embedded target system</em> where there is also
+ <item>A <em>basic target system</em> that can be started by
+ calling the ordinary <c>erl</c> script.</item>
+ <item>A <em>simple target system</em> where also code
+ replacement in runtime can be performed.</item>
+ <item>An <em>embedded target system</em> where there is also
support for logging output from the system to file for later
inspection, and where the system can be started automatically
- at boot time. </item>
+ at boot time.</item>
</list>
- <p>We only consider the case when Erlang/OTP is running on a UNIX
- system.</p>
- <p>In the <c>sasl</c> application there is an example Erlang
- module <c>target_system.erl</c> that contains functions for
- creating and installing a target system. This module is used in
- the examples below, and the source code of the module is listed
- at the end of this chapter.</p>
- </section>
+ <p>Here is only considered the case when Erlang/OTP is running on a
+ UNIX system.</p>
+ <p>The <c>sasl</c> application includes the example Erlang
+ module <c>target_system.erl</c>, which contains functions for
+ creating and installing a target system. This module is used in
+ the following examples. The source code of the module is listed
+ in <seealso marker="#listing of target system">
+ Listing of target_system.erl</seealso></p>
<section>
<marker id="create"/>
<title>Creating a Target System</title>
<p>It is assumed that you have a working Erlang/OTP system structured
- according to the OTP Design Principles.</p>
- <p><em>Step 1.</em> First create a <c>.rel</c> file (see <seealso
- marker="sasl:rel">rel(4)</seealso>) that specifies the <c>erts</c>
- version and lists all applications that should be included in the
- new basic target system. An example is the following
- <c>mysystem.rel</c> file:</p>
+ according to the OTP design principles.</p>
+ <p><em>Step 1.</em> Create a <c>.rel</c> file (see the
+ <seealso marker="sasl:rel">rel(4)</seealso> manual page in
+ SASL), which specifies the ERTS version and lists
+ all applications that are to be included in the new basic target
+ system. An example is the following <c>mysystem.rel</c> file:</p>
<code type="none">
%% mysystem.rel
{release,
@@ -91,23 +90,23 @@
{pea, "1.0"}]}.</code>
<p>The listed applications are not only original Erlang/OTP
applications but possibly also new applications that you have
- written yourself (here exemplified by the application
- <c>pea</c>). </p>
- <p><em>Step 2.</em> From the directory where the <c>mysystem.rel</c>
- file reside, start the Erlang/OTP system:</p>
+ written (here exemplified by the application Pea (<c>pea</c>)).</p>
+ <p><em>Step 2.</em> Start Erlang/OTP from the directory where
+ the <c>mysystem.rel</c> file resides:</p>
<pre>
os> <input>erl -pa /home/user/target_system/myapps/pea-1.0/ebin</input></pre>
- <p>where also the path to the <c>pea-1.0</c> ebin directory is
- provided. </p>
- <p><em>Step 3.</em> Now create the target system: </p>
+ <p>Here also the path to the <c>pea-1.0</c> ebin directory is
+ provided.</p>
+ <p><em>Step 3.</em> Create the target system:</p>
<pre>
1> <input>target_system:create("mysystem").</input></pre>
- <p>The <c>target_system:create/1</c> function does the following:</p>
+ <p>The function <c>target_system:create/1</c> performs the
+ following:</p>
<list type="ordered">
- <item>Reads the <c>mysystem.rel</c> file, and creates a new file
- <c>plain.rel</c> which is identical to former, except that it
- only lists the <c>kernel</c> and <c>stdlib</c> applications. </item>
- <item>From the <c>mysystem.rel</c> and <c>plain.rel</c> files
+ <item>Reads the file <c>mysystem.rel</c> and creates a new file
+ <c>plain.rel</c> that is identical to the former, except that it
+ only lists the Kernel and STDLIB applications.</item>
+ <item>From the files <c>mysystem.rel</c> and <c>plain.rel</c>
creates the files <c>mysystem.script</c>,
<c>mysystem.boot</c>, <c>plain.script</c>, and
<c>plain.boot</c> through a call to
@@ -124,26 +123,26 @@ releases/mysystem.rel
lib/kernel-2.16.4/
lib/stdlib-1.19.4/
lib/sasl-2.3.4/
-lib/pea-1.0/ </code>
+lib/pea-1.0/</code>
<p>The file <c>releases/FIRST/start.boot</c> is a copy of our
<c>mysystem.boot</c></p>
<p>The release resource file <c>mysystem.rel</c> is duplicated
in the tar file. Originally, this file was only stored in
- the <c>releases</c> directory in order to make it possible
+ the <c>releases</c> directory to make it possible
for the <c>release_handler</c> to extract this file
separately. After unpacking the tar
file, <c>release_handler</c> would automatically copy the
file to <c>releases/FIRST</c>. However, sometimes the tar
file is unpacked without involving
- the <c>release_handler</c> (e.g. when unpacking the first
- target system) and therefore the file is now instead
+ the <c>release_handler</c> (for example, when unpacking the
+ first target system). The file is therefore now instead
duplicated in the tar file so no manual copying is
- necessary.</p>
+ needed.</p>
</item>
- <item>Creates the temporary directory <c>tmp</c> and extracts the tar file
- <c>mysystem.tar.gz</c> into that directory. </item>
- <item>Deletes the <c>erl</c> and <c>start</c> files from
- <c>tmp/erts-5.10.4/bin</c>. These files will be created again from
+ <item>Creates the temporary directory <c>tmp</c> and extracts
+ the tar file <c>mysystem.tar.gz</c> into that directory.</item>
+ <item>Deletes the files <c>erl</c> and <c>start</c> from
+ <c>tmp/erts-5.10.4/bin</c>. These files are created again from
source when installing the release.</item>
<item>Creates the directory <c>tmp/bin</c>.</item>
<item>Copies the previously created file <c>plain.boot</c> to
@@ -151,31 +150,31 @@ lib/pea-1.0/ </code>
<item>Copies the files <c>epmd</c>, <c>run_erl</c>, and
<c>to_erl</c> from the directory <c>tmp/erts-5.10.4/bin</c> to
the directory <c>tmp/bin</c>.</item>
- <item>Creates the directory <c>tmp/log</c>, which will be used
+ <item>Creates the directory <c>tmp/log</c>, which is used
if the system is started as embedded with the <c>bin/start</c>
script.</item>
<item>Creates the file <c>tmp/releases/start_erl.data</c> with
the contents "5.10.4 FIRST". This file is to be passed as data
- file to the <c>start_erl</c> script.
- </item>
+ file to the <c>start_erl</c> script.</item>
<item>Recreates the file <c>mysystem.tar.gz</c> from the directories
- in the directory <c>tmp</c>, and removes <c>tmp</c>.</item>
+ in the directory <c>tmp</c> and removes <c>tmp</c>.</item>
</list>
</section>
<section>
<title>Installing a Target System</title>
<p><em>Step 4.</em> Install the created target system in a
- suitable directory. </p>
+ suitable directory.</p>
<pre>
2> <input>target_system:install("mysystem", "/usr/local/erl-target").</input></pre>
- <p>The function <c>target_system:install/2</c> does the following:
+ <p>The function <c>target_system:install/2</c> performs the following:
</p>
<list type="ordered">
<item>Extracts the tar file <c>mysystem.tar.gz</c> into the target
directory <c>/usr/local/erl-target</c>.</item>
- <item>In the target directory reads the file <c>releases/start_erl.data</c>
- in order to find the Erlang runtime system version ("5.10.4").</item>
+ <item>In the target directory reads the file
+ <c>releases/start_erl.data</c> to find the Erlang runtime system
+ version ("5.10.4").</item>
<item>Substitutes <c>%FINAL_ROOTDIR%</c> and <c>%EMU%</c> for
<c>/usr/local/erl-target</c> and <c>beam</c>, respectively, in
the files <c>erl.src</c>, <c>start.src</c>, and
@@ -184,97 +183,102 @@ lib/pea-1.0/ </code>
<c>start</c>, and <c>run_erl</c> in the target <c>bin</c>
directory.</item>
<item>Finally the target <c>releases/RELEASES</c> file is created
- from data in the <c>releases/mysystem.rel</c> file.</item>
+ from data in the file <c>releases/mysystem.rel</c>.</item>
</list>
</section>
<section>
<marker id="start"/>
<title>Starting a Target System</title>
- <p>Now we have a target system that can be started in various ways.</p>
- <p>We start it as a <em>basic target system</em> by invoking</p>
+ <p>Now we have a target system that can be started in various ways.
+ We start it as a <em>basic target system</em> by invoking:</p>
<pre>
os> <input>/usr/local/erl-target/bin/erl</input></pre>
- <p>where only the <c>kernel</c> and <c>stdlib</c> applications are
- started, i.e. the system is started as an ordinary development
- system. There are only two files needed for all this to work:
- <c>bin/erl</c> file (obtained from <c>erts-5.10.4/bin/erl.src</c>)
- and the <c>bin/start.boot</c> file (a copy of <c>plain.boot</c>).</p>
+ <p>Here only the Kernel and STDLIB applications are
+ started, that is, the system is started as an ordinary development
+ system. Only two files are needed for all this to work:</p>
+ <list type="ordered">
+ <item><c>bin/erl</c> (obtained from
+ <c>erts-5.10.4/bin/erl.src</c>)</item>
+ <item><c>bin/start.boot</c> (a copy of
+ <c>plain.boot</c>)</item>
+ </list>
<p>We can also start a distributed system (requires <c>bin/epmd</c>).</p>
<p>To start all applications specified in the original
- <c>mysystem.rel</c> file, use the <c>-boot</c> flag as follows:</p>
+ <c>mysystem.rel</c> file, use flag <c>-boot</c> as follows:</p>
<pre>
os> <input>/usr/local/erl-target/bin/erl -boot /usr/local/erl-target/releases/FIRST/start</input></pre>
- <p>We start a <em>simple target system</em> as above. The only difference
- is that also the file <c>releases/RELEASES</c> is present for
- code replacement in run-time to work.</p>
- <p>To start an <em>embedded target system</em> the shell script
- <c>bin/start</c> is used. That shell script calls
+ <p>We start a <em>simple target system</em> as above. The only
+ difference is that also the file <c>releases/RELEASES</c> is
+ present for code replacement in runtime to work.</p>
+ <p>To start an <em>embedded target system</em>, the shell script
+ <c>bin/start</c> is used. The script calls
<c>bin/run_erl</c>, which in turn calls <c>bin/start_erl</c>
(roughly, <c>start_erl</c> is an embedded variant of
- <c>erl</c>). </p>
+ <c>erl</c>).</p>
<p>The shell script <c>start</c>, which is generated from
erts-5.10.4/bin/start.src during installation, is only an
- example. You should edit it to suite your needs. Typically it is
+ example. Edit it to suite your needs. Typically it is
executed when the UNIX system boots.</p>
<p><c>run_erl</c> is a wrapper that provides logging of output from
- the run-time system to file. It also provides a simple mechanism
+ the runtime system to file. It also provides a simple mechanism
for attaching to the Erlang shell (<c>to_erl</c>).</p>
- <p><c>start_erl</c> requires the root directory
- (<c>"/usr/local/erl-target"</c>), the releases directory
- (<c>"/usr/local/erl-target/releases"</c>), and the location of
- the <c>start_erl.data</c> file. It reads the run-time system
- version (<c>"5.10.4"</c>) and release version (<c>"FIRST"</c>) from
- the <c>start_erl.data</c> file, starts the run-time system of the
- version found, and provides <c>-boot</c> flag specifying the boot
- file of the release version found
- (<c>"releases/FIRST/start.boot"</c>).</p>
- <p><c>start_erl</c> also assumes that there is <c>sys.config</c> in
- release version directory (<c>"releases/FIRST/sys.config"</c>). That
- is the topic of the next section (see below).</p>
- <p>The <c>start_erl</c> shell script should normally not be
+ <p><c>start_erl</c> requires:</p>
+ <list type="ordered">
+ <item>The root directory (<c>"/usr/local/erl-target"</c>)</item>
+ <item>The releases directory
+ (<c>"/usr/local/erl-target/releases"</c></item>
+ <item>The location of the file <c>start_erl.data</c></item>
+ </list>
+ <p>It performs the following:</p>
+ <list type="ordered">
+ <item>Reads the runtime system version (<c>"5.10.4"</c>) and
+ release version (<c>"FIRST"</c>) from the file
+ <c>start_erl.data</c>.</item>
+ <item>Starts the runtime system of the version found.</item>
+ <item>Provides the flag <c>-boot</c> specifying the boot
+ file of the release version found
+ (<c>"releases/FIRST/start.boot"</c>).</item>
+ </list>
+ <p><c>start_erl</c> also assumes that there is <c>sys.config</c>
+ in the release version directory (<c>"releases/FIRST/sys.config"</c>).
+ That is the topic of the next section.</p>
+ <p>The <c>start_erl</c> shell script is normally not to be
altered by the user.</p>
</section>
<section>
<title>System Configuration Parameters</title>
- <p>As was pointed out above <c>start_erl</c> requires a
- <c>sys.config</c> in the release version directory
- (<c>"releases/FIRST/sys.config"</c>). If there is no such a
- file, the system start will fail. Hence such a file has to
- be added as well.</p>
- <p></p>
- <p>If you have system configuration data that are neither file
- location dependent nor site dependent, it may be convenient to
- create the <c>sys.config</c> early, so that it becomes a part of
+ <p>As was mentioned in the previous section, <c>start_erl</c>
+ requires a <c>sys.config</c> in the release version directory
+ (<c>"releases/FIRST/sys.config"</c>). If there is no such
+ file, the system start fails. Such a file must therefore
+ also be added.</p>
+ <p>If you have system configuration data that is neither
+ file-location-dependent nor site-dependent, it can be convenient
+ to create <c>sys.config</c> early, so it becomes part of
the target system tar file created by
- <c>target_system:create/1</c>. In fact, if you create, in the
- current directory, not only the <c>mysystem.rel</c> file, but
- also a <c>sys.config</c> file, that latter file will be tacitly
+ <c>target_system:create/1</c>. In fact, if you in the
+ current directory create not only the file <c>mysystem.rel</c>,
+ but also file <c>sys.config</c>, the latter file is tacitly
put in the appropriate directory.</p>
</section>
<section>
- <title>Differences from the Install Script</title>
- <p>The above <c>install/2</c> procedure differs somewhat from that
+ <title>Differences From the Install Script</title>
+ <p>The previous <c>install/2</c> procedure differs somewhat from that
of the ordinary <c>Install</c> shell script. In fact, <c>create/1</c>
makes the release package as complete as possible, and leave to the
- <c>install/2</c> procedure to finish by only considering location
- dependent files.</p>
+ <c>install/2</c> procedure to finish by only considering
+ location-dependent files.</p>
</section>
<section>
<title>Creating the Next Version</title>
-
- <p>
- In this example the <c>pea</c> application has been changed, and
- so are <c>erts</c>, <c>kernel</c>, <c>stdlib</c> and
- <c>sasl</c>.
- </p>
-
- <p>
- <em>Step 1.</em> Create the <c>.rel</c> file:
- </p>
+ <p>In this example the Pea application has been changed, and
+ so are the applications ERTS, Kernel, STDLIB
+ and SASL.</p>
+ <p><em>Step 1.</em> Create the file <c>.rel</c>:</p>
<code type="none">
%% mysystem2.rel
{release,
@@ -284,65 +288,49 @@ os> <input>/usr/local/erl-target/bin/erl -boot /usr/local/erl-target/releases/FI
{stdlib, "2.0"},
{sasl, "2.4"},
{pea, "2.0"}]}.</code>
- <p>
- <em>Step 2.</em> Create the application upgrade file (see
- <seealso marker="sasl:appup">appup(4)</seealso>) for <c>pea</c>,
- for example:
- </p>
+ <p><em>Step 2.</em> Create the application upgrade file (see the
+ <seealso marker="sasl:appup">appup(4)</seealso> manual page in
+ SASL) for Pea, for example:</p>
<code type="none">
%% pea.appup
{"2.0",
[{"1.0",[{load_module,pea_lib}]}],
[{"1.0",[{load_module,pea_lib}]}]}.</code>
- <p>
- <em>Step 3.</em> From the directory where the
- <c>mysystem2.rel</c> file reside, start the Erlang/OTP system:
- </p>
+ <p><em>Step 3.</em> From the directory where the file
+ <c>mysystem2.rel</c> resides, start the Erlang/OTP system,
+ giving the path to the new version of Pea:</p>
<pre>
os> <input>erl -pa /home/user/target_system/myapps/pea-2.0/ebin</input></pre>
- <p>giving the path to the new version of <c>pea</c>. </p>
-
- <p>
- <em>Step 4.</em> Create the release upgrade file (see <seealso
- marker="sasl:relup">relup(4)</seealso>):
- </p>
+ <p><em>Step 4.</em> Create the release upgrade file (see the
+ <seealso marker="sasl:relup">relup(4)</seealso> manual page in
+ SASL):</p>
<pre>
-1> <input>systools:make_relup("mysystem2",["mysystem"],["mysystem"],[{path,["/home/user/target_system/myapps/pea-1.0/ebin","/my/old/erlang/lib/*/ebin"]}]).</input></pre>
- <p>
- where <c>"mysystem"</c> is the base release and
- <c>"mysystem2"</c> is the release to upgrade to.
- </p>
- <p>
- Note that the <c>path</c> option is used for pointing out the
+1> <input>systools:make_relup("mysystem2",["mysystem"],["mysystem"],
+ [{path,["/home/user/target_system/myapps/pea-1.0/ebin",
+ "/my/old/erlang/lib/*/ebin"]}]).</input></pre>
+ <p>Here <c>"mysystem"</c> is the base release and
+ <c>"mysystem2"</c> is the release to upgrade to.</p>
+ <p>The <c>path</c> option is used for pointing out the
old version of all applications. (The new versions are already
- in the code path - assuming of course that the erlang node on
+ in the code path - assuming of course that the Erlang node on
which this is executed is running the correct version of
- Erlang/OTP.)
- </p>
- <p>
- <em>Step 5.</em> Create the new release:
- </p>
+ Erlang/OTP.)</p>
+ <p><em>Step 5.</em> Create the new release:</p>
<pre>
2> <input>target_system:create("mysystem2").</input></pre>
- <p>
- Given that the <c>relup</c> file generated in step 4 above is
- now located in the current directory, it will automatically be
- included in the release package.
- </p>
+ <p>Given that the file <c>relup</c> generated in Step 4 is
+ now located in the current directory, it is automatically
+ included in the release package.</p>
</section>
<section>
<title>Upgrading the Target System</title>
- <p>
- This part is done on the target node, and for this example we
+ <p>This part is done on the target node, and for this example we
want the node to be running as an embedded system with the
- <c>-heart</c> option, allowing automatic restart of the
- node. See <seealso marker="#start">Starting a Target
- System</seealso> above for more information.
- </p>
- <p>
- We add <c>-heart</c> to <c>bin/start</c>:
- </p>
+ <c>-heart</c> option, allowing automatic restart of the node.
+ For more information, see <seealso marker="#start">
+ Starting a Target System</seealso>.</p>
+ <p>We add <c>-heart</c> to <c>bin/start</c>:</p>
<code type="none">
#!/bin/sh
ROOTDIR=/usr/local/erl-target/
@@ -354,36 +342,27 @@ fi
START_ERL_DATA=${1:-$RELDIR/start_erl.data}
-$ROOTDIR/bin/run_erl -daemon /tmp/ $ROOTDIR/log "exec $ROOTDIR/bin/start_erl $ROOTDIR $RELDIR $START_ERL_DATA -heart</code>
- <p>
- And we use the simplest possible <c>sys.config</c>, which we
- store in <c>releases/FIRST</c>:
- </p>
+$ROOTDIR/bin/run_erl -daemon /tmp/ $ROOTDIR/log "exec $ROOTDIR/bin/start_erl $ROOTDIR\
+$RELDIR $START_ERL_DATA -heart</code>
+ <p>We use the simplest possible <c>sys.config</c>, which we
+ store in <c>releases/FIRST</c>:</p>
<code type="none">
%% sys.config
[].</code>
- <p>
- Finally, in order to prepare the upgrade, we need to put the new
+ <p>Finally, to prepare the upgrade, we must put the new
release package in the <c>releases</c> directory of the first
- target system:
- </p>
+ target system:</p>
<pre>
os> <input>cp mysystem2.tar.gz /usr/local/erl-target/releases</input></pre>
- <p>
- And assuming that the node has been started like this:
- </p>
+ <p>Assuming that the node has been started as follows:</p>
<pre>
os> <input>/usr/local/erl-target/bin/start</input></pre>
- <p>
- it can be accessed like this:
- </p>
+ <p>It can be accessed as follows:</p>
<pre>
os> <input>/usr/local/erl-target/bin/to_erl /tmp/erlang.pipe.1</input></pre>
- <p>
- Also note that logs can be found in
+ <p>Logs can be found in
<c>/usr/local/erl-target/log</c>. This directory is specified as
- an argument to <c>run_erl</c>in the start script listed above.
- </p>
+ an argument to <c>run_erl</c>in the start script listed above.</p>
<p>
<em>Step 1.</em> Unpack the release:
</p>
@@ -402,18 +381,19 @@ heart: Tue Apr 1 12:15:11 2014: Executed "/usr/local/erl-target/bin/start /usr/
The above return value and output after the call to
<c>release_handler:install_release/1</c> means that the
<c>release_handler</c> has restarted the node by using
- <c>heart</c>. This will always be done when the upgrade involves
- a change of <c>erts</c>, <c>kernel</c>, <c>stdlib</c> or
- <c>sasl</c>. See <seealso marker="upgrade">Upgrade when
- Erlang/OTP has Changed</seealso> for more infomation about this.
+ <c>heart</c>. This is always done when the upgrade involves
+ a change of the applications ERTS, Kernel,
+ STDLIB, or SASL. For more information, see
+ <seealso marker="upgrade">
+ Upgrade when Erlang/OTP has Changed</seealso>.
</p>
<p>
- The node will be accessible via a new pipe:
+ The node is accessible through a new pipe:
</p>
<pre>
os> <input>/usr/local/erl-target/bin/to_erl /tmp/erlang.pipe.2</input></pre>
<p>
- Let's see which releases we have in our system:
+ Check which releases there are in the system:
</p>
<pre>
1> <input>release_handler:which_releases().</input>
@@ -426,7 +406,7 @@ os> <input>/usr/local/erl-target/bin/to_erl /tmp/erlang.pipe.2</input></pre>
<p>
Our new release, "SECOND", is now the current release, but we
can also see that our "FIRST" release is still permanent. This
- means that if the node would be restarted at this point, it
+ means that if the node would be restarted now, it
would come up running the "FIRST" release again.
</p>
<p>
@@ -434,11 +414,9 @@ os> <input>/usr/local/erl-target/bin/to_erl /tmp/erlang.pipe.2</input></pre>
</p>
<pre>
2> <input>release_handler:make_permanent("SECOND").</input></pre>
-
<p>
- Now look at the releases again:
+ Check the releases again:
</p>
-
<pre>
3> <input>release_handler:which_releases().</input>
<output>[{"MYSYSTEM","SECOND",
@@ -447,19 +425,16 @@ os> <input>/usr/local/erl-target/bin/to_erl /tmp/erlang.pipe.2</input></pre>
{"MYSYSTEM","FIRST",
["kernel-2.16.4","stdlib-1.19.4","sasl-2.3.4","pea-1.0"],
old}]</output></pre>
-
<p>
- Here we see that the new release version is <c>permanent</c>, so
- it would be safe to restart the node.
- </p>
-
+ We see that the new release version is <c>permanent</c>, so
+ it would be safe to restart the node.</p>
</section>
<section>
+ <marker id="listing of target system"/>
<title>Listing of target_system.erl</title>
<p>This module can also be found in the <c>examples</c> directory
- of the <c>sasl</c> application.</p>
+ of the SASL application.</p>
<codeinclude file="../../../lib/sasl/examples/src/target_system.erl" tag="%module" type="erl"></codeinclude>
-
</section>
</chapter>
diff --git a/system/doc/system_principles/error_logging.xml b/system/doc/system_principles/error_logging.xml
index 80d5211323..3a82f4e0e0 100644
--- a/system/doc/system_principles/error_logging.xml
+++ b/system/doc/system_principles/error_logging.xml
@@ -28,41 +28,43 @@
<rev></rev>
<file>error_logging.xml</file>
</header>
+ <marker id="error logging"></marker>
<section>
<title>Error Information From the Runtime System</title>
<p>Error information from the runtime system, that is, information
- about a process terminating due to an uncaught error exception,
+ about a process terminating because of an uncaught error exception,
is by default written to terminal (tty):</p>
<code type="none"><![CDATA[
=ERROR REPORT==== 9-Dec-2003::13:25:02 ===
Error in process <0.27.0> with exit value: {{badmatch,[1,2,3]},[{m,f,1},{shell,eval_loop,2}]}]]></code>
<p>The error information is handled by the <em>error logger</em>, a
system process registered as <c>error_logger</c>. This process
- receives all error messages from the Erlang runtime system and
- also from the standard behaviours and different Erlang/OTP
+ receives all error messages from the Erlang runtime system as
+ well as from the standard behaviours and different Erlang/OTP
applications.</p>
- <p>The exit reasons (such as <c>badarg</c> above) used by
+ <p>The exit reasons (such as <c>badarg</c>) used by
the runtime system are described in
- <seealso marker="doc/reference_manual:errors#exit_reasons">Errors and Error Handling</seealso>
- in the Erlang Reference Manual.</p>
- <p>The process <c>error_logger</c> and its user interface (with
- the same name) are described in
- <seealso marker="kernel:error_logger">error_logger(3)</seealso>.
- It is possible to configure the system so that error information
- is written to file instead/as well as tty. Also, it is possible
- for user defined applications to send and format error
- information using <c>error_logger</c>.</p>
+ <seealso marker="doc/reference_manual:errors#exit_reasons">
+ Errors and Error Handling</seealso>.</p>
+ <p>For information about the process <c>error_logger</c> and its user
+ interface (with the same name), see the
+ <seealso marker="kernel:error_logger">error_logger(3)</seealso>
+ manual page in Kernel. The system can be configured so that
+ error information
+ is written to file or to tty, or both. In addition, user-defined
+ applications can send and format error information using
+ <c>error_logger</c>.</p>
</section>
<section>
<title>SASL Error Logging</title>
- <p>The standard behaviors (<c>supervisor</c>, <c>gen_server</c>,
- etc.) sends progress and error information to <c>error_logger</c>.
- If the SASL application is started, this information is written
- to tty as well. See
+ <p>The standard behaviours (<c>supervisor</c>, <c>gen_server</c>,
+ and so on) send progress and error information to <c>error_logger</c>.
+ If the SASL application is started, this information is
+ written to tty as well. For more information, see
<seealso marker="sasl:error_logging">SASL Error Logging</seealso>
- in the SASL User's Guide for further information.</p>
+ in the SASL User's Guide.</p>
<pre>
% <input>erl -boot start_sasl</input>
Erlang (BEAM) emulator version 5.4.13 [hipe] [threads:0] [kernel-poll]
diff --git a/system/doc/system_principles/system_principles.xml b/system/doc/system_principles/system_principles.xml
index 79ed86cd9f..5718e8a3f6 100644
--- a/system/doc/system_principles/system_principles.xml
+++ b/system/doc/system_principles/system_principles.xml
@@ -28,35 +28,41 @@
<rev></rev>
<file>system_principles.xml</file>
</header>
+ <marker id="system principles"></marker>
<section>
<title>Starting the System</title>
- <p>An Erlang runtime system is started with the command <c>erl</c>:</p>
+ <p>An Erlang runtime system is started with command <c>erl</c>:</p>
<pre>
% <input>erl</input>
Erlang/OTP 17 [erts-6.0] [hipe] [smp:8:8]
Eshell V6.0 (abort with ^G)
1> </pre>
- <p><c>erl</c> understands a number of command line arguments, see
- <c>erl(1)</c>. A number of them are also described in this chapter.</p>
- <p>Application programs can access the values of the command line
- arguments by calling one of the functions
- <c>init:get_argument(Key)</c>, or <c>init:get_arguments()</c>.
- See <c>init(3)</c>.</p>
+ <p><c>erl</c> understands a number of command-line arguments, see
+ the <seealso marker="erts:erl">erl(1)</seealso> manual page in
+ ERTS. Some of them are also described in this chapter.</p>
+ <p>Application programs can access the values of the command-line
+ arguments by calling the function <c>init:get_argument(Key)</c>
+ or <c>init:get_arguments()</c>. See the
+ <seealso marker="erts:init">init(3)</seealso> manual page in
+ ERTS.</p>
</section>
<section>
<title>Restarting and Stopping the System</title>
- <p>The runtime system can be halted by calling <c>halt/0,1</c>.
- See <c>erlang(3)</c>.</p>
- <p>The module <c>init</c> contains function for restarting,
- rebooting and stopping the runtime system. See <c>init(3)</c>.</p>
+ <p>The runtime system is halted by calling <c>halt/0,1</c>. For
+ details, see the <seealso marker="erts:erlang">erlang(3)</seealso>
+ manual page in ERTS.</p>
+ <p>The module <c>init</c> contains functions for restarting,
+ rebooting, and stopping the runtime system:</p>
<pre>
init:restart()
init:reboot()
init:stop()</pre>
- <p>Also, the runtime system will terminate if the Erlang shell is
+ <p>For details, see the <seealso marker="erts:init">init(3)</seealso>
+ manual page in ERTS.</p>
+ <p>The runtime system terminates if the Erlang shell is
terminated.</p>
</section>
@@ -69,14 +75,15 @@ init:stop()</pre>
<p>A boot script file has the extension <c>.script</c>.
The runtime system uses a binary version of the script. This
<em>binary boot script</em> file has the extension <c>.boot</c>.</p>
- <p>Which boot script to use is specified by the command line flag
- <c>-boot</c>. The extension <c>.boot</c> should be omitted.
- Example, using the boot script <c>start_all.boot</c>:</p>
+ <p>Which boot script to use is specified by the command-line flag
+ <c>-boot</c>. The extension <c>.boot</c> is to be omitted.
+ For example, using the boot script <c>start_all.boot</c>:</p>
<pre>
% <input>erl -boot start_all</input></pre>
<p>If no boot script is specified, it defaults to
- <c>ROOT/bin/start</c>, see Default Boot Scripts below.</p>
- <p>The command line flag <c>-init_debug</c> makes the <c>init</c>
+ <c>ROOT/bin/start</c>, see <seealso marker="#default_boot_scripts">
+ Default Boot Scripts</seealso>.</p>
+ <p>The command-line flag <c>-init_debug</c> makes the <c>init</c>
process write some debug information while interpreting the boot
script:</p>
<pre>
@@ -87,59 +94,55 @@ init:stop()</pre>
{start,heart}
{start,error_logger}
...</pre>
- <p>See <c>script(4)</c> for a detailed description of the syntax
- and contents of the boot script.</p>
+ <p>For a detailed description of the syntax and contents of the
+ boot script, see the <c>script(4)</c> manual page in SASL.</p>
<section>
+ <marker id="default_boot_scripts"></marker>
<title>Default Boot Scripts</title>
- <p>Erlang/OTP comes with two boot scripts:</p>
- <taglist>
- <tag><c>start_clean.boot</c></tag>
- <item>
- <p>Loads the code for and starts the applications Kernel and
- STDLIB.</p>
- </item>
- <tag><c>start_sasl.boot</c></tag>
- <item>
- <p>Loads the code for and starts the applications Kernel,
- STDLIB and SASL.</p>
- </item>
- <tag><c>no_dot_erlang.boot</c></tag>
- <item>
- <p>Loads the code for and starts the applications Kernel and
- STDLIB, skips loading the <c>.erlang</c> file.
- Useful for scripts and other tools that should be behave the
- same regardless of user preferences.
- </p>
- </item>
- </taglist>
+ <p>Erlang/OTP comes with these boot scripts:</p>
+ <list type="bulleted">
+ <item><c>start_clean.boot</c> - Loads the code for and starts
+ the applications Kernel and STDLIB.</item>
+ <item><c>start_sasl.boot</c> - Loads the code for and starts
+ the applications Kernel, STDLIB, and
+ SASL).</item>
+ <item><c>no_dot_erlang.boot</c> - Loads the code for and
+ starts the applications Kernel and STDLIB.
+ Skips loading the file <c>.erlang</c>. Useful for scripts and
+ other tools that are to behave the same irrespective of user
+ preferences.</item>
+ </list>
<p>Which of <c>start_clean</c> and <c>start_sasl</c> to use as
default is decided by the user when installing Erlang/OTP using
<c>Install</c>. The user is asked "Do you want to use a minimal
system startup instead of the SASL startup". If the answer is
yes, then <c>start_clean</c> is used, otherwise
- <c>start_sasl</c> is used. A copy of the selected boot script
- is made, named <c>start.boot</c> and placed in
- the <c>ROOT/bin</c> directory.</p>
+ <c>start_sasl</c> is used. A copy of the selected boot script is
+ made, named <c>start.boot</c> and placed in directory
+ <c>ROOT/bin</c>.</p>
</section>
<section>
<title>User-Defined Boot Scripts</title>
<p>It is sometimes useful or necessary to create a user-defined
boot script. This is true especially when running Erlang in
- embedded mode, see <seealso marker="#code_loading">Code Loading Strategy</seealso>.</p>
- <p>It is possible to write a boot script manually.
- The recommended way to create a boot script, however, is to
- generate the boot script from a release resource file
- <c>Name.rel</c>, using the function
+ embedded mode, see <seealso marker="#code_loading">
+ Code Loading Strategy</seealso>.</p>
+ <p>A boot script can be written manually. However, it is
+ recommended to create a boot script by generating it from a
+ release resource file <c>Name.rel</c>, using the function
<c>systools:make_script/1,2</c>. This requires that the source
code is structured as applications according to the OTP design
principles. (The program does not have to be started in terms of
- OTP applications but can be plain Erlang).</p>
- <p>Read more about <c>.rel</c> files in OTP Design Principles and
- <c>rel(4)</c>.</p>
+ OTP applications, but can be plain Erlang).</p>
+ <p>For more information about <c>.rel</c> files, see
+ <seealso marker="otp design principles">
+ OTP Design Principles</seealso> and the
+ <seealso marker="sasl:rel">rel(4)</seealso> manual page in
+ SASL.</p>
<p>The binary boot script file <c>Name.boot</c> is generated from
- the boot script file <c>Name.script</c> using the function
+ the boot script file <c>Name.script</c>, using the function
<c>systools:script2boot(File)</c>.</p>
</section>
</section>
@@ -148,16 +151,17 @@ init:stop()</pre>
<marker id="code_loading"></marker>
<title>Code Loading Strategy</title>
<p>The runtime system can be started in either <em>embedded</em> or
- <em>interactive</em> mode. Which one is decided by the command
- line flag <c>-mode</c>.</p>
+ <em>interactive</em> mode. Which one is decided by the
+ command-line flag <c>-mode</c>.</p>
<pre>
% <input>erl -mode embedded</input></pre>
<p>Default mode is <c>interactive</c>.</p>
+ <p>The mode properties are as follows:</p>
<list type="bulleted">
- <item>In embedded mode, all code is loaded during system start-up
+ <item>In embedded mode, all code is loaded during system startup
according to the boot script. (Code can also be loaded later
- by explicitly ordering the code server to do so).</item>
- <item>In interactive mode, code is dynamically loaded when first
+ by explicitly ordering the code server to do so.)</item>
+ <item>In interactive mode, the code is dynamically loaded when first
referenced. When a call to a function in a module is made, and
the module is not loaded, the code server searches the code path
and loads the module into the system.</item>
@@ -165,21 +169,21 @@ init:stop()</pre>
<p>Initially, the code path consists of the current
working directory and all object code directories under
<c>ROOT/lib</c>, where <c>ROOT</c> is the installation directory
- of Erlang/OTP. Directories can be named <c>Name[-Vsn]</c> and
- the code server, by default, chooses the directory with
+ of Erlang/OTP. Directories can be named <c>Name[-Vsn]</c>. The
+ code server, by default, chooses the directory with
the highest version number among those which have the same
<c>Name</c>. The <c>-Vsn</c> suffix is optional. If an
<c>ebin</c> directory exists under the <c>Name[-Vsn]</c>
- directory, it is this directory which is added to the code path.</p>
- <p>The code path can be extended by using the command line flags
- <c>-pa Directories</c> and <c>-pz Directories</c>. These will add
- <c>Directories</c> to the head or end of the code path,
- respectively. Example</p>
+ directory, this directory is added to the code path.</p>
+ <p>The code path can be extended by using the command-line flags
+ <c>-pa Directories</c> and <c>-pz Directories</c>. These add
+ <c>Directories</c> to the head or the end of the code path,
+ respectively. Example:</p>
<pre>
% <input>erl -pa /home/arne/mycode</input></pre>
<p>The code server module <c>code</c> contains a number of
- functions for modifying and checking the search path, see
- <c>code(3)</c>.</p>
+ functions for modifying and checking the search path, see the
+ <c>code(3)</c> manual page in Kernel.</p>
</section>
<section>
@@ -192,49 +196,65 @@ init:stop()</pre>
<cell align="left" valign="middle"><em>Documented in</em></cell>
</row>
<row>
- <cell align="left" valign="middle">module</cell>
+ <cell align="left" valign="middle">Module</cell>
<cell align="left" valign="middle"><c>.erl</c></cell>
- <cell align="left" valign="middle">Erlang Reference Manual</cell>
+ <cell align="left" valign="middle">
+ <seealso marker="erlang ref manual">
+ Erlang Reference Manual</seealso></cell>
</row>
<row>
- <cell align="left" valign="middle">include file</cell>
+ <cell align="left" valign="middle">Include file</cell>
<cell align="left" valign="middle"><c>.hrl</c></cell>
- <cell align="left" valign="middle">Erlang Reference Manual</cell>
+ <cell align="left" valign="middle">
+ <seealso marker="erlang ref manual">
+ Erlang Reference Manual</seealso></cell>
</row>
<row>
- <cell align="left" valign="middle">release resource file</cell>
+ <cell align="left" valign="middle">Release resource file</cell>
<cell align="left" valign="middle"><c>.rel</c></cell>
- <cell align="left" valign="middle"><c>rel(4)</c></cell>
+ <cell align="left" valign="middle">
+ <seealso marker="sasl:rel">rel(4)</seealso>
+ manual page in SASL</cell>
</row>
<row>
- <cell align="left" valign="middle">application resource file</cell>
+ <cell align="left" valign="middle">Application resource file</cell>
<cell align="left" valign="middle"><c>.app</c></cell>
- <cell align="left" valign="middle"><c>app(4)</c></cell>
+ <cell align="left" valign="middle">
+ <seealso marker="kernel:app">app(4)</seealso>
+ manual page in Kernel</cell>
</row>
<row>
- <cell align="left" valign="middle">boot script</cell>
+ <cell align="left" valign="middle">Boot script</cell>
<cell align="left" valign="middle"><c>.script</c></cell>
- <cell align="left" valign="middle"><c>script(4)</c></cell>
+ <cell align="left" valign="middle">
+ <seealso marker="sasl:script">script(4)</seealso>
+ manual page in SASL</cell>
</row>
<row>
- <cell align="left" valign="middle">binary boot script</cell>
+ <cell align="left" valign="middle">Binary boot script</cell>
<cell align="left" valign="middle"><c>.boot</c></cell>
<cell align="left" valign="middle">-</cell>
</row>
<row>
- <cell align="left" valign="middle">configuration file</cell>
+ <cell align="left" valign="middle">Configuration file</cell>
<cell align="left" valign="middle"><c>.config</c></cell>
- <cell align="left" valign="middle"><c>config(4)</c></cell>
+ <cell align="left" valign="middle">
+ <seealso marker="kernel:config">config(4)</seealso>
+ manual page in Kernel</cell>
</row>
<row>
- <cell align="left" valign="middle">application upgrade file</cell>
+ <cell align="left" valign="middle">Application upgrade file</cell>
<cell align="left" valign="middle"><c>.appup</c></cell>
- <cell align="left" valign="middle"><c>appup(4)</c></cell>
+ <cell align="left" valign="middle">
+ <seealso marker="sasl:appup">appup(4)</seealso>
+ manual page in SASL</cell>
</row>
<row>
- <cell align="left" valign="middle">release upgrade file</cell>
+ <cell align="left" valign="middle">Release upgrade file</cell>
<cell align="left" valign="middle"><c>relup</c></cell>
- <cell align="left" valign="middle"><c>relup(4)</c></cell>
+ <cell align="left" valign="middle">
+ <seealso marker="sasl:relup">relup(4)</seealso>
+ manual page in SASL</cell>
</row>
<tcaption>File Types</tcaption>
</table>
diff --git a/system/doc/system_principles/upgrade.xml b/system/doc/system_principles/upgrade.xml
index 68e48da0b8..83e8128f94 100644
--- a/system/doc/system_principles/upgrade.xml
+++ b/system/doc/system_principles/upgrade.xml
@@ -31,88 +31,72 @@
<rev></rev>
<file>upgrade.xml</file>
</header>
+ <marker id="upgrade section"></marker>
<section>
<title>Introduction</title>
- <p>
- As of Erlang/OTP 17, most applications deliver a valid
- application upgrade (<c>appup</c>) file. In earlier releases, a
+ <marker id="upgrade"></marker>
+ <p>As of Erlang/OTP 17, most applications deliver a valid
+ application upgrade file (<c>appup</c>). In earlier releases, a
majority of the applications in Erlang/OTP did not support
- upgrade at all. Many of the applications use the
+ upgrade. Many of the applications use the
<c>restart_application</c> instruction. These are applications
for which it is not crucial to support real soft upgrade, for
- instance tools and library applications. The
+ example, tools and library applications. The
<c>restart_application</c> instruction
ensures that all modules in the application are reloaded and
- thereby running the new code.
- </p>
+ thereby running the new code.</p>
</section>
<section>
- <title>Upgrade of core applications</title>
- <p>
- The core applications ERTS, Kernel, STDLIB
+ <title>Upgrade of Core Applications</title>
+ <p>The core applications ERTS, Kernel, STDLIB,
and SASL never allow real soft upgrade, but require the
Erlang emulator to be restarted. This is indicated to the
<c>release_handler</c> by the upgrade instruction
- <c>restart_new_emulator</c>. This instruction will always be the
- very first instruction executed, and it will restart the
+ <c>restart_new_emulator</c>. This instruction is always the
+ very first instruction executed, and it restarts the
emulator with the new versions of the above mentioned core
- applications and the old versions of all other
- applications. When the node is back up all other upgrade instructions are
+ applications and the old versions of all other applications.
+ When the node is back up, all other upgrade instructions are
executed, making sure each application is finally running its
- new version.
- </p>
-
- <p>
- It might seem strange to do a two-step upgrade instead of
+ new version.</p>
+ <p>It might seem strange to do a two-step upgrade instead of
just restarting the emulator with the new version of all
applications. The reason for this design decision is to allow
- <c>code_change</c> functions to have side effects, for example changing
- data on disk. It also makes sure that the upgrade mechanism for
- non-core applications does not differ depending on whether or not
- core applications are changed at the same time.
- </p>
-
- <p>
- If, however, the more brutal variant is preferred, it is
- possible to handwrite the release upgrade file using only the
+ <c>code_change</c> functions to have side effects, for example,
+ changing data on disk. It also guarantees that the upgrade
+ mechanism for non-core applications does not differ depending
+ on whether or not core applications are changed at the same time.</p>
+ <p>If, however, the more brutal variant is preferred, the
+ the release upgrade file can be handwritten using only the
single upgrade instruction <c>restart_emulator</c>. This
- instruction, in contrast to <c>restart_new_emulator</c>, will
- cause the emulator to restart with the new versions of
- <em>all</em> applications.
- </p>
-
- <p>
- <em>Note</em> that if other instructions are included before
+ instruction, in contrast to <c>restart_new_emulator</c>,
+ causes the emulator to restart with the new versions of
+ <em>all</em> applications.</p>
+ <p><em>Note:</em> If other instructions are included before
<c>restart_emulator</c> in the handwritten <c>relup</c> file,
- they will be executed in the old emulator. This is a big risk
+ they are executed in the old emulator. This is a big risk
since there is no guarantee that new beam code can be loaded
into the old emulator. Adding instructions after
<c>restart_emulator</c> has no effect as the
- <c>release_handler</c> will not do any attempt at executing
- them.
- </p>
-
- <p>
- See <seealso marker="sasl:relup">relup(4)</seealso> for
- information about the release upgrade file, and <seealso
- marker="sasl:appup">appup(4)</seealso> for further information
- about upgrade instructions.
- </p>
+ <c>release_handler</c> will not execute them.</p>
+ <p>For information about the release upgrade file, see the
+ <seealso marker="sasl:relup">relup(4)</seealso> manual page
+ in SASL.
+ For more information about upgrade instructions, see the
+ <seealso marker="sasl:appup">appup(4)</seealso> manual page
+ in SASL.</p>
</section>
<section>
- <title>Applications that still do not allow code upgrade</title>
- <p>
- A few applications, for instance HiPE do not support
- upgrade at all. This is indicated by an application upgrade file
- containing only <c>{Vsn,[],[]}</c>. Any attempt at creating a release
- upgrade file with such input will fail.
- The only way to force an upgrade involving applications like this is to
- handwrite the <c>relup</c> file, preferably as described above
- with only the <c>restart_emulator</c> instruction.
- </p>
-
+ <title>Applications that Still do Not Allow Code Upgrade</title>
+ <p>A few applications, such as HiPE, do not support upgrade.
+ This is indicated by an application upgrade file containing only
+ <c>{Vsn,[],[]}</c>. Any attempt at creating a release upgrade file
+ with such input fails. The only way to force an upgrade involving
+ applications like this is to
+ handwrite the file <c>relup</c>, preferably as described above
+ with only the <c>restart_emulator</c> instruction.</p>
</section>
</chapter>
diff --git a/system/doc/system_principles/versions.xml b/system/doc/system_principles/versions.xml
index ff042f4a3b..25eb90f626 100644
--- a/system/doc/system_principles/versions.xml
+++ b/system/doc/system_principles/versions.xml
@@ -31,93 +31,99 @@
<rev></rev>
<file>versions.xml</file>
</header>
- <section><title>OTP Version</title>
+ <marker id="versions section"></marker>
+
+ <section>
+ <title>OTP Version</title>
<p>As of OTP release 17, the OTP release number corresponds to
the major part of the OTP version. The OTP version as a concept was
- introduced in OTP 17. The <seealso marker="#version_scheme">version
- scheme</seealso> used is described in more detail below.</p>
-
+ introduced in OTP 17. The version scheme used is described in detail in
+ <seealso marker="#version_scheme">Version Scheme</seealso>.</p>
<p>OTP of a specific version is a set of applications of specific
versions. The application versions identified by an OTP version
corresponds to application versions that have been tested together
- by the Erlang/OTP team at Ericsson AB. An OTP system can however be
+ by the Erlang/OTP team at Ericsson AB. An OTP system can, however, be
put together with applications from different OTP versions. Such a
combination of application versions has not been tested by the
Erlang/OTP team. It is therefore <em>always preferred to use OTP
applications from one single OTP version</em>.</p>
-
<p>Release candidates have an <c>-rc&lt;N&gt;</c>
- suffix. The suffix <c>-rc0</c> will be used during development up to
+ suffix. The suffix <c>-rc0</c> is used during development up to
the first release candidate.</p>
- <section><title>Retrieving Current OTP Version</title>
- <p>In an OTP source code tree, the OTP version can be read from
- the text file <c>&lt;OTP source root&gt;/OTP_VERSION</c>. The
- absolute path to the file can be constructed by calling
- <c>filename:join([<seealso marker="kernel:code#root_dir/0">code:root_dir()</seealso>, "OTP_VERSION"])</c>.</p>
- <p>In an installed OTP development system, the OTP version can be read
- from the text file <c>&lt;OTP installation root&gt;/releases/&lt;OTP release number&gt;/OTP_VERSION</c>.
- The absolute path to the file can by constructed by calling
- <c>filename:join([<seealso marker="kernel:code#root_dir/0">code:root_dir()</seealso>, "releases", <seealso marker="erts:erlang#system_info_otp_release">erlang:system_info(otp_release)</seealso>, "OTP_VERSION"]).</c></p>
- <p>If the version read from the <c>OTP_VERSION</c> file in a
- development system has a <c>**</c> suffix, the system has been
- patched using the <c>otp_patch_apply</c> tool available to
- licensed customers. In this case, the system consists of application
- versions from multiple OTP versions. The version preceding the <c>**</c>
- suffix corresponds to the OTP version of the base system that
- has been patched. Note that if a development system is updated by
- other means than <c>otp_patch_apply</c>, the <c>OTP_VERSION</c> file
- may identify an incorrect OTP version.</p>
-
- <p>No <c>OTP_VERSION</c> file will be placed in a
- <seealso marker="create_target">target system</seealso> created
- by OTP tools. This since one easily can create a target system
- where it is hard to even determine the base OTP version. You may,
- however, place such a file there yourself if you know the OTP
- version.</p>
+ <section>
+ <title>Retrieving Current OTP Version</title>
+ <p>In an OTP source code tree, the OTP version can be read from
+ the text file <c>&lt;OTP source root&gt;/OTP_VERSION</c>. The
+ absolute path to the file can be constructed by calling
+ <c>filename:join([<seealso marker="kernel:code#root_dir/0">code:root_dir()</seealso>, "OTP_VERSION"])</c>.</p>
+ <p>In an installed OTP development system, the OTP version can be read
+ from the text file <c>&lt;OTP installation root&gt;/releases/&lt;OTP release number&gt;/OTP_VERSION</c>.
+ The absolute path to the file can by constructed by calling
+ <c>filename:join([<seealso marker="kernel:code#root_dir/0">code:root_dir()</seealso>, "releases", <seealso marker="erts:erlang#system_info_otp_release"> erlang:system_info(otp_release)</seealso>, "OTP_VERSION"]).</c></p>
+ <p>If the version read from the <c>OTP_VERSION</c> file in a
+ development system has a <c>**</c> suffix, the system has been
+ patched using the <c>otp_patch_apply</c> tool available to
+ licensed customers. In this case, the system consists of application
+ versions from multiple OTP versions. The version preceding the <c>**</c>
+ suffix corresponds to the OTP version of the base system that
+ has been patched. Notice that if a development system is updated by
+ other means than <c>otp_patch_apply</c>, the file <c>OTP_VERSION</c>
+ can identify an incorrect OTP version.</p>
+ <p>No <c>OTP_VERSION</c> file is placed in a
+ <seealso marker="create_target">target system</seealso> created
+ by OTP tools. This since one easily can create a target system
+ where it is hard to even determine the base OTP version. You can,
+ however, place such a file there if you know the OTP version.</p>
</section>
- <section><title>OTP Versions Table</title>
- <p>The text file <c>&lt;OTP source root&gt;/otp_versions.table</c> that
- is part of the source code contains information about all OTP versions
- from OTP 17.0 up to current OTP version. Each line contains information
- about application versions that are part of a specific OTP version, and
- is on the format:</p>
-<pre>
-&lt;OtpVersion&gt; : &lt;ChangedAppVersions&gt; # &lt;UnchangedAppVersions&gt; :
-</pre>
- <p><c>&lt;OtpVersion&gt;</c> is on the format <c>OTP-&lt;VSN&gt;</c>, i.e.,
- the same as the git tag used to identify the source.
- <c>&lt;ChangedAppVersions&gt;</c> and <c>&lt;UnchangedAppVersions&gt;</c>
- are space separated lists of application versions on the
- format <c>&lt;application&gt;-&lt;vsn&gt;</c>.
- <c>&lt;ChangedAppVersions&gt;</c> corresponds to changed applications
- with new version numbers in this OTP version, and
- <c>&lt;UnchangedAppVersions&gt;</c> corresponds to unchanged application
- versions in this OTP version. Both of them might be empty, although
- not at the same time. If &lt;ChangedAppVersions&gt; is empty, no changes
- has been made that change the build result of any application. This could
- for example be a pure bug fix of the build system. The order of lines
- is undefined. All white space characters in this file are either space
- (character 32) or line-break (character 10).</p>
- <p>Using ordinary UNIX tools like <c>sed</c> and <c>grep</c> one
- can easily find answers to various questions like:</p>
- <taglist>
- <tag>Which OTP versions are <c>kernel-3.0</c> part of?</tag>
- <item><p><c> $ grep ' kernel-3\.0 ' otp_versions.table</c></p></item>
- <tag>In which OTP version was <c>kernel-3.0</c> introduced?</tag>
- <item><p><c> $ sed 's/#.*//;/ kernel-3\.0 /!d' otp_versions.table</c></p></item>
- </taglist>
- <p>The above commands give a bit more information than the exact answers,
- but adequate information when manually searching for answers to these
- questions.</p>
- <warning><p>The format of the <c>otp_versions.table</c> might be subject
- to changes during the OTP 17 release.</p></warning>
- </section>
+ <section>
+ <title>OTP Versions Table</title>
+ <p>The text file <c>&lt;OTP source root&gt;/otp_versions.table</c>,
+ which is part of the source code, contains information about all
+ OTP versions from OTP 17.0 up to the current OTP version. Each line
+ contains information about application versions that are part of a
+ specific OTP version, and has the following format:</p>
+ <pre>
+&lt;OtpVersion&gt; : &lt;ChangedAppVersions&gt; # &lt;UnchangedAppVersions&gt; :</pre>
+ <p><c>&lt;OtpVersion&gt;</c> has the format <c>OTP-&lt;VSN&gt;</c>,
+ that is, the same as the git tag used to identify the source.</p>
+ <p><c>&lt;ChangedAppVersions&gt;</c> and
+ <c>&lt;UnchangedAppVersions&gt;</c> are space-separated lists of
+ application versions and has the format
+ <c>&lt;application&gt;-&lt;vsn&gt;</c>.</p>
+ <list type="bulleted">
+ <item><c>&lt;ChangedAppVersions&gt;</c> corresponds to changed
+ applications with new version numbers in this OTP version.</item>
+ <item><c>&lt;UnchangedAppVersions&gt;</c> corresponds to unchanged
+ application versions in this OTP version.</item>
+ </list>
+ <p>Both of them can be empty, but not at the same time.
+ If <c>&lt;ChangedAppVersions&gt;</c> is empty, no changes have
+ been made that change the build result of any application. This could,
+ for example, be a pure bug fix of the build system. The order of lines
+ is undefined. All white-space characters in this file are either space
+ (character 32) or line-break (character 10).</p>
+ <p>By using ordinary UNIX tools like <c>sed</c> and <c>grep</c> one
+ can easily find answers to various questions like:</p>
+ <list type="bulleted">
+ <item><p>Which OTP versions are <c>kernel-3.0</c> part of?</p>
+ <p><c>$ grep ' kernel-3\.0 ' otp_versions.table</c> </p></item>
+ <item><p>In which OTP version was <c>kernel-3.0</c> introduced?</p>
+ <p><c>$ sed 's/#.*//;/ kernel-3\.0 /!d' otp_versions.table</c>
+ </p></item>
+ </list>
+ <p>The above commands give a bit more information than the exact
+ answers, but adequate information when manually searching for answers
+ to these questions.</p>
+ <warning><p>The format of the <c>otp_versions.table</c> might be
+ subject to changes during the OTP 17 release.</p></warning>
</section>
+ </section>
- <section><title>Application Version</title>
- <p>As of OTP 17.0 application versions will use the same
+ <section>
+ <title>Application Version</title>
+ <p>As of OTP 17.0 application versions use the same
<seealso marker="#version_scheme">version scheme</seealso> as the
OTP version. Application versions part of a release candidate will
however not have an <c>-rc&lt;N&gt;</c> suffix as the OTP version.
@@ -125,88 +131,88 @@
necessarily imply a major increment of the OTP version. This depends
on whether the major change in the application is considered as a
major change for OTP as a whole or not.</p>
- </section>
+ </section>
+ <section>
+ <title>Version Scheme</title>
<marker id="version_scheme"/>
- <section><title>Version Scheme</title>
- <note>Note that the version scheme was changed as of OTP 17.0. This implies
+ <note><p>The version scheme was changed as of OTP 17.0. This implies
that application versions used prior to OTP 17.0 do not adhere to this
version scheme. <seealso marker="#otp_17_0_app_versions">A list of
- application versions used in OTP 17.0</seealso> can be found
- at the end of this document.</note>
-
- <p>In the normal case, a version will be constructed as
- <c>&lt;Major&gt;.&lt;Minor&gt;.&lt;Patch&gt;</c> where <c>&lt;Major&gt;</c>
- is the most significant part. However, more dot separated parts than
- this may exist. The dot separated parts consists of non-negative integers.
- If all parts less significant than <c>&lt;Minor&gt;</c> equals <c>0</c>,
- they are omitted. The three normal parts
- <c>&lt;Major&gt;.&lt;Minor&gt;.&lt;Patch&gt;</c> will be changed as
+ application versions used in OTP 17.0</seealso> is included at the
+ end of this section</p></note>
+ <p>In the normal case, a version is constructed as
+ <c>&lt;Major&gt;.&lt;Minor&gt;.&lt;Patch&gt;</c>,
+ where <c>&lt;Major&gt;</c> is the most significant part.</p>
+ <p>However, more dot-separated parts than this can exist.
+ The dot-separated parts consist of non-negative integers. If
+ all parts less significant than <c>&lt;Minor&gt;</c> equals
+ <c>0</c>, they are omitted. The three normal parts
+ <c>&lt;Major&gt;.&lt;Minor&gt;.&lt;Patch&gt;</c> are changed as
follows:</p>
- <taglist>
- <tag><c>&lt;Major&gt;</c></tag><item>Increased when major changes,
- including incompatibilities, have been made.</item>
- <tag><c>&lt;Minor&gt;</c></tag><item>Increased when new functionality
- has been added.</item>
- <tag><c>&lt;Patch&gt;</c></tag><item>Increased when pure bug fixes
- have been made.</item>
- </taglist>
- <p>When a part in the version number is increased, all less significant
+ <list type="bulleted">
+ <item><c>&lt;Major&gt;</c> - Increases when major changes,
+ including incompatibilities, are made.</item>
+ <item><c>&lt;Minor&gt;</c> - Increases when new
+ functionality is added.</item>
+ <item><c>&lt;Patch&gt;</c> - Increases when pure bug fixes
+ are made.</item>
+ </list>
+ <p>When a part in the version number increases, all less significant
parts are set to <c>0</c>.</p>
-
<p>An application version or an OTP version identifies source code
- versions. That is, it does not imply anything about how the application
+ versions. That is, it implies nothing about how the application
or OTP has been built.</p>
- <section><title>Order of Versions</title>
- <p>Version numbers in general are only partially ordered. However,
- normal version numbers (with three parts) as of OTP 17.0 have a total
- or linear order. This applies both to normal OTP versions and
- normal application versions.</p>
-
- <p>When comparing two version numbers that have an order, one
- compare each part as ordinary integers from the most
- significant part towards less significant parts. The order is
- defined by the first parts of the same significance that
- differ. An OTP version with a larger version include all
- changes that that are part of a smaller OTP version. The same
- goes for application versions.</p>
-
- <p>In the general case, versions may have more than three parts. In
- this case the versions are only partially ordered. Note that such
- versions are only used in exceptional cases. When an extra
- part (out of the normal three parts) is added to a version number,
- a new branch of versions is made. The new branch has a linear
- order against the base version. However, versions on different
- branches have no order. Since they have no order, we
- only know that they all include what is included in their
- closest common ancestor. When branching multiple times from the
- same base version, <c>0</c> parts are added between the base
- version and the least significant <c>1</c> part until a unique
- version is found. Versions that have an order can be compared
- as described in the paragraph above.</p>
-
- <p>An example of branched versions: The version <c>6.0.2.1</c>
- is a branched version from the base version <c>6.0.2</c>.
- Versions on the form <c>6.0.2.&lt;X&gt;</c> can be compared
- with normal versions smaller than or equal to <c>6.0.2</c>,
- and other versions on the form <c>6.0.2.&lt;X&gt;</c>. The
- version <c>6.0.2.1</c> will include all changes in
- <c>6.0.2</c>. However, <c>6.0.3</c> will most likely
- <em>not</em> include all changes in <c>6.0.2.1</c> (note that
- these versions have no order). A second branched version from the base
- version <c>6.0.2</c> will be version <c>6.0.2.0.1</c>, and a
- third branched version will be <c>6.0.2.0.0.1</c>.</p>
- </section>
+ <section>
+ <title>Order of Versions</title>
+ <p>Version numbers in general are only partially ordered. However,
+ normal version numbers (with three parts) as of OTP 17.0 have a total
+ or linear order. This applies both to normal OTP versions and
+ normal application versions.</p>
+ <p>When comparing two version numbers that have an order, one
+ compare each part as ordinary integers from the most
+ significant part to less significant parts. The order is
+ defined by the first parts of the same significance that
+ differ. An OTP version with a larger version includes all
+ changes that are part of a smaller OTP version. The same
+ goes for application versions.</p>
+ <p>In general, versions can have more than three parts.
+ The versions are then only partially ordered. Such
+ versions are only used in exceptional cases. When an extra
+ part (out of the normal three parts) is added to a version number,
+ a new branch of versions is made. The new branch has a linear
+ order against the base version. However, versions on different
+ branches have no order, and therefore one can only conclude
+ that they all include what is included in their
+ closest common ancestor. When branching multiple times from the
+ same base version, <c>0</c> parts are added between the base
+ version and the least significant <c>1</c> part until a unique
+ version is found. Versions that have an order can be compared
+ as described in the previous paragraph.</p>
+ <p>An example of branched versions: The version <c>6.0.2.1</c>
+ is a branched version from the base version <c>6.0.2</c>.
+ Versions on the form <c>6.0.2.&lt;X&gt;</c> can be compared
+ with normal versions smaller than or equal to <c>6.0.2</c>,
+ and other versions on the form <c>6.0.2.&lt;X&gt;</c>. The
+ version <c>6.0.2.1</c> will include all changes in
+ <c>6.0.2</c>. However, <c>6.0.3</c> will most likely
+ <em>not</em> include all changes in <c>6.0.2.1</c> (note that
+ these versions have no order). A second branched version from the base
+ version <c>6.0.2</c> will be version <c>6.0.2.0.1</c>, and a
+ third branched version will be <c>6.0.2.0.0.1</c>.</p>
</section>
+ </section>
+ <section>
+ <title>OTP 17.0 Application Versions</title>
<marker id="otp_17_0_app_versions"/>
- <section><title>OTP 17.0 Application Versions</title>
- <p>The following application versions were part of OTP 17.0. If
- the normal part of an applications version number compares
- as smaller than the corresponding application version in this list,
+ <p>The following list details the application versions that
+ were part of OTP 17.0. If
+ the normal part of an application version number compares
+ as smaller than the corresponding application version in the list,
the version number does not adhere to the version scheme introduced
- in OTP 17.0 and should be considered as not having an order against
+ in OTP 17.0 and is to be considered as not having an order against
versions used as of OTP 17.0.</p>
<list>
<item><c>asn1-3.0</c></item>
@@ -262,6 +268,6 @@
<item><c>wx-1.2</c></item>
<item><c>xmerl-1.3.7</c></item>
</list>
- </section>
+ </section>
</chapter>