In a Dedicated Server Configuration a Server Process handles
requests for a Single User Process

smon is background process in a sga.
its name is system monitor.function is monitering the system
its used for database recovery when database is crash.

smon is used for rolling forward the committed data and 
rolling back the rollback data.smon writes commited data 
from log buffer to data files.

its a background process.its used when archive log parameter
enabled.its making archive file.archive file is a replica 
of redolog file.

A Shared SQL area is required to process every unique SQL 
statement submitted to a database and contains information
such as the parse tree and execution plan for the
corresponding statement. 

In a Multi-threaded Server Configuration many user processes
share a group of server process.