P and T processes don't terminate--why?

We're running Oracle 6.0.33 on a Sparc-10 and have noticed that processes controlling connections to the database are hanging around taking up memory. We had a situation this morning where the databases wouldn't come up and on doing a process list, saw 11 processes of this type:

oracle 27349 0.0 0.0 488 0 ? IW 08:20 0:00 oracle<SID> P:4096,3,6, oracle 27971 0.0 0.0 356 0 ? IW 08:30 0:01 oracle<SID> T:I,1024,5

Combined, these processes were taking up 150M of memory. Ordinarily, these processes should die when the databases are brought down. For some reason they did not terminate. I killed each one using kill -15 and was then able to restart the databases without problems.

Does anyone know if this is a known problem which has been solved in 6.0.36? This has been a recurring problem for us.

-- 
Peter Steele        Unix Services Manager            peter.steele_at_acadiau.ca 
Acadia Univ., Wolfville, NS, Canada B0P 1X0  902-542-2201  Fax: 902-542-4364