SUMMARY: Two CPUs under 4.1.4

From: Jan-Olaf Droese (
Date: Wed Aug 18 1999 - 09:10:38 CDT

Sorry for the delayed summery, but I have been out of town for a couple of

Most of the replies I've got stated that the configuration I'm asking for
is not officially supported by Sun but will probably work. Jochen Bern
<> wrote that he has a Sparc20 with two
CPUs running fine under 4.1.3_U1, so 4.1.4 will probably also work.

Nearly anyone who answered pointed out that the multiprocessor
capabilities of SunOS 4 are not comparable to those of Solaris 2.
Adding a second CPU will not give you the same speed-up as it does
with Solaris 2. Also it is important to use CPUs of exactly the same
type. Mixing CPUs won't work.

Thanks to all who answered,


Original question was:

we have an old Sparc20 which is still running 4.1.4 and (for many reasons)
can't be upgraded to Solaris 2 in the near future.
Since we are running out of CPU-cycles, I'd like to put in another CPU of
the same type. I know that with >= 5.5 this will work without any problems,
the machine will run as stable as before, but with twice the CPU-power.
What do I have to expect when I drop in the second CPU? Will it still run
as stable as it does now, or does 4.1.4 have problems with more than one=20
CPU? Are there any gotchas I should be aware of?

Jan-Olaf Droese         | Lahmeyer International GmbH | #include
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