<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE chapter SYSTEM "chapter.dtd">

<chapter>
  <header>
    <copyright>
      <year>1997</year>
      <year>2021</year>
      <holder>Ericsson AB, All Rights Reserved</holder>
    </copyright>
    <legalnotice>
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
 
      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

  The Initial Developer of the Original Code is Ericsson AB.
    </legalnotice>

    <title>Erlang on embedded systems</title>
    <prepared>Fredrik Tillman</prepared>
    <responsible></responsible>
    <docno>ETX/B/SFP/TILLMAN:96-001</docno>
    <approved></approved>
    <checked></checked>
    <date>1997-11-12</date>
    <rev>PA1</rev>
    <file>intro.sgml</file>
  </header>
  <p>This manual is a complement to the other manuals and describes how
    to install, run and maintain Erlang on an embedded system.
    </p>
  <p>For more information about how to install and start Erlang read 
    XXXXXXXX.
    </p>

  <section>
    <title>Memory Usage</title>
    <p>Solaris takes about 17 Mbyte of RAM on a system with 64 Mbyte of
      total RAM. This leaves about 47 Mbyte for the applications. If
      the system utilizes swapping, these figures cannot be improved
      because unnecessary daemon processes are swapped out. However,
      if swapping is disabled, or if the swap space is a precious
      resource in the system, it becomes necessary to kill off
      unnecessary daemon processes.
      </p>
    <p>The following start-scripts can be deleted to
      prevent unnecessary daemons from starting:
      </p>
    <list type="bulleted">
      <item><c>/etc/rc2.d/S72autoinstall</c></item>
      <item><c>/etc/rc2.d/S74autofs</c></item>
      <item><c>/etc/rc2.d/S76nscd</c></item>
      <item><c>/etc/rc2.d/S80PRESERVE</c></item>
      <item><c>/etc/rc2.d/S80lp</c></item>
      <item><c>/etc/rc2.d/S88sendmail</c></item>
      <item><c>/etc/rc2.d/S92volmgt</c></item>
      <item><c>/etc/rc2.d/S93cacheos.finish</c></item>
      <item><c>/etc/rc3.d/S15nfs.server</c></item>
    </list>
    <p>More information is expected from Sun on how to modify the
      kernel in order to reduce the memory consumption. This will be
      performed by modifying the <c>/etc/system</c> file.</p>
  </section>

  <section>
    <title>Disk Space Usage</title>
    <p>The disk space required by Solaris can be minimized by using the
      Core User support installation. It requires about 80 Mbyte of
      disk space. This installs only the minimum software required to
      boot and run Solaris.  The disk space can be further reduced by
      deleting unnecessary individual files. However, unless disk
      space is a critical resource the effort required and the risks
      involved may not be justified.</p>
  </section>

  <section>
    <title>Other Issues</title>
    <p>Future releases of OTP will include more information on how
      Solaris can be configured for use with embedded systems to get
      maximum performance. Issues which will be investigated include:
      </p>
    <list type="bulleted">
      <item>how disabling swapping affects the system</item>
      <item>how locking processes in memory may yield performance benefits.</item>
    </list>
  </section>
</chapter>

