To start up Earthworm automatically on a unix machine boot, you can put it in the /etc/init.d scripts.

Here's an example from a Linux box:

We've got our Earthworm directories set like this:

/opt/earthworm/earthworm_7.3
/opt/earthworm/active_ew <- this is a link to the above; always the active EW version
/opt/earthworm/run_working/params
/opt/earthworm/run_working/logs
The contents of /etc/init.d/earthworm is:
#!/bin/sh
#This is the earthworm software start up script
EW=/opt/earthworm
EW_PARAMS=/opt/earthworm/run_working/params
export EW_PARAMS
case "$1" in
        start)
                if [ ! -f $EW/start_earthworm.sh ]
                then
                        echo "earthworm startup: cannot find start script start_earthworm.sh"  > $EW/run_working/logs/start_earthworm.log 2>&1 &
                        exit
                fi
                su rtem -c $EW/start_earthworm.sh > $EW/run_working/logs/start_earthworm.log 2>&1 &
                ;;
        stop)
                su rtem -c $EW/active_ew/bin/pau
                ;;
        restart)
                $0 stop
                $0 start
                ;;
        *)
                echo "usage: start " # stop|start|restart"
                ;;
esac

We've got this symlink:
/etc/rc3.d/S99earthworm -> /etc/init.d/earthworm

The contents of /opt/earthworm/start_earthworm.sh is:

#!/bin/bash
# Start up earthworm in background
cd /opt/earthworm/active_ew
source /opt/earthworm/run_working/params/ew_linux.bash
startstop >& /opt/earthworm/run_working/logs/startstop &