[rescue] What to do with the SS20

[Steven M Jones]

On 06/22/2014 05:37 PM, Sandwich Maker wrote:
> " Also, I believe all SunOS 4 releases can only have one CPU executing
> " kernel code at a time. I'm not sure if technically you have to call that
> " asymmetric multiprocessing, rather than SMP.
>
> now that you mention this, i think you're right.  it wasn't a problem
> for ${WORK[1995]}, as we were doing complex fpga layouts and sims, and
> 2 cpus meant the engineers - and the systems - could do useful work on
> one cpu while the big heavy sim app hogged the other one.

I was at a place for most of 1991 where I first met Solbourne gear, and
one major use was to run Synopsys and other EDA software. Whatever the
task, the Solbournes just soaked up the load and kept going.

> ... solbourne dug into the kernel
> code and implemented fine-grained spinlocks, but sun basically just
> put one giant spinlock around the entire kernel.  since solbourne
> licensed sun's codebase, why couldn't sun just build on their work?

I suspect the answer lies with the work Sun was already doing on SVR4
with AT&T in the late 80s, so that they already had a path that would
lead there with the new OS. Why do more than temporarily hold off the
threat from Solbourne and others until that was ready?  But I wouldn't
mind finding out from those in the know. Especially if it's something
like, "Oh, we didn't think they'd do that, so we didn't include it in
the license terms..."

--S.