It is recommended that the embedded environment is run by an ordinary user, that is, a user who does not have super user privileges.

In this section, it is assumed that the username is otpuser and that the home directory of that user is:

        /export/home/otpuser

It is also assumed that in the home directory of otpuser, there is a directory named otp, the full path of which is:

        /export/home/otpuser/otp

This directory is the installation directory of the embedded environment.

The procedure for installing an embedded system is the same as for an ordinary system (see Installation Guide), except for the following:

A true embedded system must start when the system boots. This section accounts for the necessary configurations needed to achieve that.

The embedded system and all the applications start automatically if the script file shown below is added to directory /etc/rc3.d. The file must be owned and readable by root. Its name cannot be arbitrarily assigned; the following name is recommended:

        S75otp.system

For more details on initialization (and termination) scripts, and naming thereof, see the Solaris documentation.

#!/bin/sh
#  
#  File name:  S75otp.system
#  Purpose:    Automatically starts Erlang and applications when the 
#              system starts
#  Author:     janne@erlang.ericsson.se
#  Resides in: /etc/rc3.d
#

if [ ! -d /usr/bin ]
then                    # /usr not mounted
        exit
fi

killproc() {            # kill the named process(es)
        pid=`/usr/bin/ps -e |
             /usr/bin/grep -w $1 |
             /usr/bin/sed -e 's/^  *//' -e 's/ .*//'`
        [ "$pid" != "" ] && kill $pid
}

# Start/stop processes required for Erlang

case "$1" in
'start')
        # Start the Erlang emulator
        #
        su - otpuser -c "/export/home/otpuser/otp/bin/start" &
        ;;
'stop')
        killproc beam
        ;;
*)
        echo "Usage: $0 { start | stop }"
        ;;
esac

File /export/home/otpuser/otp/bin/start referred to in the above script is precisely the start script described in Starting Erlang. The script variable OTP_ROOT in that start script corresponds to the following example path used in this section:

        /export/home/otpuser/otp

The start script is to be edited accordingly.

Use of the killproc procedure in the above script can be combined with a call to erl_call, for example:

        $SOME_PATH/erl_call -n Node init stop

To take Erlang down gracefully, see the erl_call(1) manual page in erl_interface for details on the use of erl_call. However, that requires that Erlang runs as a distributed node, which is not always the case.

The killproc procedure is not to be removed. The purpose is here to move from run level 3 (multi-user mode with networking resources) to run level 2 (multi-user mode without such resources), in which Erlang is not to run.

For Solaris running on VME boards from Force Computers, the onboard hardware watchdog can be activated, provided a VME bus driver is added to the operating system (see also Installation Problems).

See also the heart(3) manual page in Kernel.

If the HEART_COMMAND environment variable is to be set in the start script in Starting Erlang, and if the value is to be set to the path of the Solaris reboot command, that is:

        HEART_COMMAND=/usr/sbin/reboot

then the ownership and file permissions for /usr/sbin/reboot must be changed as follows:

        chown 0 /usr/sbin/reboot
        chmod 4755 /usr/sbin/reboot

See also the heart(3) manual page in Kernel.

When the Erlang runtime system is automatically started from the S75otp.system script, the TERM environment variable must be set. The following is a minimal setting:

        TERM=sun

This is to be added to the start script.

For proper functioning of flushing file system data to disk on Solaris 2.5.1, the version-specific patch with number 103640-02 must be added to the operating system. Other patches might be needed, see the release README file /README]]>.

The following four installation procedures require super user privilege:

          [{os_mon, [{start_os_sup, true}, {os_sup_own, "/etc"}, 
          {os_sup_syslogconf, "/etc/syslog.conf"}, {os_sup_errortag, std_error}]}].

The hardware watchdog timer, which is controlled by the heart port program, requires package FORCEvme, which contains the VME bus driver, to be installed. However, this driver can clash with the Sun mcp driver and cause the system to refuse to boot. To cure this problem, the following lines are to be added to /etc/system:

This program is called when the machine is started. It can be modified or rewritten to suit a special system. By default, it must be called start and reside in /bin]]>. Another start program can be used, by using configuration parameter start_prg in application SASL.

The start program must call run_erl as shown below. It must also take an optional parameter, which defaults to /releases/start_erl.data]]>.

This program is to set static parameters and environment variables such as -sname Name and HEART_COMMAND to reboot the machine.

The ]]> directory is where new release packets are installed, and where the release handler keeps information about releases. For more information, see the release_handler(3) manual page in SASL.

The following script illustrates the default behaviour of the program:

The following script illustrates a modification where the node is given the name cp1, and where the environment variables HEART_COMMAND and TERM have been added to the previous script:

If a diskless and/or read-only client node is about to start, file start_erl.data is located in the client directory at the master node. Thus, the START_ERL_DATA line is to look like:

This program is used to start the emulator, but you will not be connected to the shell. to_erl is used to connect to the Erlang shell.

Here:

Log files are written in log_dir. Each log file has a name of the form erlang.log.N, where N is a generation number, ranging from 1 to 5. Each log file holds up to 100 kB text. As time goes by, the following log files are found in the log file directory:

The most recent log file is the rightmost in each row. That is, the most recent file is the one with the highest number, or if there are already four files, the one before the skip.

When a log file is opened (for appending or created), a time stamp is written to the file. If nothing has been written to the log files for 15 minutes, a record is inserted that says that we are still alive.

This program is used to attach to a running Erlang runtime system, started with run_erl.

Here pipe_name defaults to /tmp/erlang.pipe.N.

To disconnect from the shell without exiting the Erlang system, type Ctrl-D.

This program starts the Erlang emulator with parameters -boot and -config set. It reads data about where these files are located from a file named start_erl.data, which is located in ]]>. Each new release introduces a new data file. This file is automatically generated by the release handler in Erlang.

The following script illustrates the behaviour of the program:

If a diskless and/or read-only client node with the SASL configuration parameter static_emulator set to true is about to start, the -boot and -config flags must be changed.

As such a client cannot read a new start_erl.data file (the file cannot be changed dynamically). The boot and config files are always fetched from the same place (but with new contents if a new release has been installed).

The release_handler copies these files to the bin directory in the client directory at the master nodes whenever a new release is made permanent.

Assuming the same CLIENTDIR as above, the last line is to look like: