Well, I can give you an example (in Unix anyway). When Oracle starts up, it initiates several 'processes' - DBWR, LGWR, PMON, SMON, - all background processes. You'll see these in the database as sessions without usernames. In Dedicated server mode (vs. shared server), each new 'session' to the db also gets 1 server 'process'. Now that session can spawn additional Oracle processes (parallel server for example), or perhaps autonomous transactions (not sure if they get their own process or not). On Windows, there is one Oracle process, and the process has multiple threads. I think the processes parameter limits the number of threads the Oracle process can own. Now, in Shared Server (formally MTS), each session does not equal one process, as they are handled through the dispatcher and shared server processes. That's really just the surface, but I hope it helps. Chris Taylor Sr. Oracle DBA Ingram Barge Company Nashville, TN 37205 Office: 615-517-3355 Cell: 615-354-4799 Email: chris.taylor@xxxxxxxxxxxxxxx -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Mir M. Mirhashimali Sent: Tuesday, October 30, 2007 11:45 AM To: oracle-l Subject: processes vs sessions Good morning, can somebody explain what is the difference between Processes and Sessions init paramaters. Thanks -- Mir M. Mirhashimali Oracle Systems Manager Database Architecture, Enterprise Applications Rice University (713) 348 6365 -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l