Oracle get ospid from spid & get ospid from sid

Get ospid from sid

set lines 150  
col username for a15  
col osuser for a10
col machine for a15  
col program for a20  
select b.spid, a.username, a.program, a.osuser, a.machine, a.sid, a.serial#, a.status 
from gv$session a, gv$process b  
where addr=paddr(+) and sid=&sid;

Get sid from ospid

 col sid format 999999 
col username format a20 
col osuser format a15 
select b.spid,a.sid, a.serial#, a.username, a.osuser 
from v$session a, v$process b  
where a.paddr= b.addr and b.spid='&spid'
order by b.spid;