🚀 go-pugleaf

(I've removed the Distribution line; why limit things like this
to the US?)

In <1992Sep11.121830.17069@hubcap.clemson.edu> zilla@nj.nec.com (John Lewis) writes:
| Someone told me that the SGI multiprocessor machines cannot run
| different unix processes on different processors; they can only
| run a single (but possibly parallelized) process at a given time.

This is completely incorrect.  You can run multiple threads of
one process, or completely seperate processes on each CPU.

| The reason was said to be that the machines do not implement
| any mechanism for simultaneous writes.

There is a bus called the MP or Sync bus that handles cache
coherency issues.  If a process with multiple threads, or
seperate processes use shared memory, they need to provide
some mechanism (normally the hardware spinlocks or higher
level library routines based on them) to avoid attempts
at simultaneous access to the same memory locations (if
they care).

| Is the new sun multiprocessor (4/690?) similar?

It is 'similar' in that multiple processes can run on multiple
CPUs.  The exact methods used for semaphoring are different.
--
Let no one tell me that silence gives consent,  |   Dave Olson
because whoever is silent dissents.             |   Silicon Graphics, Inc.
    Maria Isabel Barreno                        |   olson@sgi.com