Is UMS threads different from worker threads ?

I have read that there is only one UMS thread per processor . So for a 4 way
box, there are only 4 UMS threads . What are the default 255 worker threads
then ?
So if i have 5 processes that want to run in parallel... does that mean only
1 process will be worked upon while the remaining 4 would be queued to be
processed ? Can someone bring some more light here ?Hassan,
I think what you call UMS threads are listener threads that put work in the
scheduler queue and wakeup sleeping/waiting threads.
(most of )The other threads are scheduled to work for the client that has a
connection to sqlserver, everything ranging from network I/O, disk I/O,
sqlprocessing, etc is done by the other worker threads. WHen a thread does
an I/O (network or disk) it will wait/sleep until the I/O event finishes.
The (worker) thread is then availabel for other work. When the I/O finishes
it (the sql process) it is rescheduled again.
.
--
Mario
www.sqlinternals.com
"Hassan" <fatima_ja@.hotmail.com> wrote in message
news:eJ5H0B$lDHA.2732@.TK2MSFTNGP11.phx.gbl...
> I have read that there is only one UMS thread per processor . So for a 4
way
> box, there are only 4 UMS threads . What are the default 255 worker
threads
> then ?
> So if i have 5 processes that want to run in parallel... does that mean
only
> 1 process will be worked upon while the remaining 4 would be queued to be
> processed ? Can someone bring some more light here ?
>sql