Oracle Automated Start

From http://download.oracle.com/docs/cd/B19306_01/server.102/b15658/strt_stp.htm#CFAHAHGA
2.2.2 Automating Database Startup and Shutdown on Other Operating Systems

To automate database startup and shutdown by using the dbstart and dbshut scripts:

Log in as the root user.

Edit the oratab file for your platform.

To open the file, use one of the following commands:

On Solaris:

# vi /var/opt/oracle/oratab
On AIX, HP-UX, Linux, and Tru64 UNIX:

# vi /etc/oratab
Database entries in the oratab file are displayed in the following format:

SID:ORACLE_HOME:{Y|N|W}
In this example, the values Y and N specify whether you want the scripts to start up or shut down the database, respectively. For each database for which you want to automate shutdown and startup, first determine the instance identifier (SID) for that database, which is identified by the SID in the first field. Then, change the last field for each to Y.

You can set dbstart to autostart a single-instance database that uses an Automatic Storage Management installation that is auto-started by Oracle Clusterware. This is the default behavior for an Automatic Storage Management cluster. If you want to do this, then you must change the oratab entry of the database and the Automatic Storage Management installation to use a third field with the value W and N, respectively. These values specify that dbstart auto-starts the database only after the Automatic Storage Management instance is started.

Note:
If you add new database instances to the system and if you want to automate startup for them, then you must edit the entries for those instances in the oratab file.