Question about 'user process' in the context of Oracle
an user process is a piece of software
  that can connect to an oracle server.
  You (the user) can start a piece of
  this kind of software, then connect to
  oracle.


Not quite. A User Process in Oracle is different than a client, which is what I think you are referring to. The user starts a client program (SQL*Plus, Pro*C, etc.), which runs on the client system. This program contacts the Oracle database server, typically either via TNS or IPC. It is the Oracle database that spawns the User Process. It's a bit confusing terminology in that a User Process from the database perspective is really just another process that Oracle starts, but it is specific to a user's connection to the database - it is a server process. It is outside of the user's direct control.