It is recommended that the Embedded Environment is run by an ordinary user, i.e. a user who does not have super user privileges.

Throughout this section we assume that the user name is otpuser, and that the home directory of that user is,

        /export/home/otpuser

Furthermore, we assume 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 installation of an embedded system does not differ from that of an ordinary system (see the Installation Guide), except for the following:

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

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

        S75otp.system

For further 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

The file /export/home/otpuser/otp/bin/start referred to in the above script, is precisely the script start described in the section Starting Erlang below. The script variable OTP_ROOT in that start script corresponds to the example path

        /export/home/otpuser/otp

used in this section. The start script should be edited accordingly.

Use of the killproc procedure in the above script could be combined with a call to erl_call, e.g.

        $SOME_PATH/erl_call -n Node init stop

In order to take Erlang down gracefully see the erl_call(1) reference manual page for further details on the use of erl_call. That however requires that Erlang runs as a distributed node which is not always the case.

The killproc procedure should not 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 should not run.

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

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

If the HEART_COMMAND environment variable is to be set in the start script in the section, Starting Erlang, and if the value shall be set to the path of the Solaris reboot command, i.e.

        HEART_COMMAND=/usr/sbin/reboot

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) reference manual page in Kernel.

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

        TERM=sun

which should be added to the start script described in the section.

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. There may be other patches 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 the FORCEvme package, which contains the VME bus driver, to be installed. This driver, however, may clash with the Sun mcp driver and cause the system to completely refuse to boot. To cure this problem, the following lines should be added to /etc/system:

This program is called when the machine is started. It may be modified or re-written to suit a special system. By default, it must be called start and reside in /bin]]>. Another start program can be used, by using the configuration parameter start_prg in the 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 should 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. See release_handler(3) in the application sasl for further information.

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 the environment variables HEART_COMMAND and TERM have been added to the above script.

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

Where pipe_dir/ should be /tmp/ (to_erl uses this name by default) and log_dir is where the log files are written. command [parameters] is executed, and everything written to stdin and stdout is logged in the log_dir.

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

with the most recent logfile being the right most in each row of the above list. 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 logfile 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're still alive.

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

Where 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 called start_erl.data which is located in the ]]>. 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 is not possible to change 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 this 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 should look like: