prstat log

Hi All,

Operating System and Version: SunOS,Solaris 10 sparc(64 bit)
RDBMS Version: 10.2.0.4.0

But the prstat logs of my system shows:-
NPROC USERNAME SWAP RSS MEMORY TIME CPU
83 cemsbin 5204M 3604M 22% 53:46:00 6.7%
2 adm 244M 240M 1.5% 15:13:53 3.5%
77 oracle 17G 10G 65% 4:24:47 0.8%
140 root 1723M 480M 2.9% 1:43:33 0.7%
3 sys 1632K 3544K 0.0% 0:00:00 0.5%
Total: 486 processes, 3850 lwps, load averages: 3.77, 4.45, 4.94

What does the MEMORY denotes?
Is it the %memory used from RAM?
Or is the %memory used by user it has been allocated?
What does these parameters denote:-
NPROC USERNAME SWAP RSS MEMORY TIME CPU?

Is the %memory usage of oracle user in the prstat log normal?
Should it affect the system and apparently cause system to crash?

Please confirm whether the oracle user can use more memory than the SGA+PGA taken together.

Thanks in advance.