Unix Top.PID and V$session.Process

[Sharma]

Try this one:

select substr(S.username,1,8) username, substr(osuser,1,10) osuser, process osprocess,
substr(machine,1,20) host,substr(P.terminal,1,10) terminal, type, sid, S.serial#,
substr(S.program ,1,25) program
from v$session S, V$PROCESS P
where P.pid = '123160'
and S.paddr=P.addr

OS process id is basically stored in pid column of V$PROCESS.