problem with shared memory

[Tod Pike]

I recently had a problem submitted to me that I thought the net would be
able to help with.  A group here has a system that uses shared memory
extensively.  This application works fine on a Microvax, but they were
having problems with it on Suns (3/60's).  The first process would create
a shared memory segment, and attach to it OK, but a second process could
not attach to the segment, getting EINVAL.

I "fixed" the problem by replacing the more or less generic kernel on
their 3/60's with a kernel config'd just for their machine.  Both configs
had the "options IPCSHMEM", "options IPCSEMAPHORE" and "options
IPCMESSAGE" set.  I am mystified as to why the specific kernel worked and
the generic kernel did not.  Any ideas?

	Much Thanks,
	Tod Pike

tgp at sei.cmu.edu
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, PA.  15213