[SunRescue] Loads

[James Lockwood]

On Thu, 9 Mar 2000, Peter Koch wrote:

> They never sold any machine with four SM-61 or faster. The
> only four CPU configuration that sun supported ever was the
> SS20-514, e.g. two 50 MHz dual cpu modules with 1MB supercache
> each. The reason was simple: Four 60 MHZ (or faster) would
> clog the M-Bus and run slower than four 50 MHz cpus.

Actually no.  Sun experimented with a SS20/614 configuration internally,
but they determined that it was highly likely to melt the machine into a
pile of slag.  There was simply no way to cool those CPU's effectively in
that tight chassis, the /514 config was already marginal.

> Notice that the Hypersparc have only 256 kb cache...

Some also had 512KB or 1MB.  Ross was able to do high-speed quad CPU's
largely due to advancements in their fab technology which let them produce
cooler running CPU's.

I'm not saying that mbus saturation doesn't occur, it certainly does.  If
your app has highly localized access patterns, though, this is much less
of an issue.

-James