Subject: Re: SMP on older, nonstandard types of i386?
To: Jon Lindgren <firstname.lastname@example.org>
From: None <email@example.com>
Date: 09/27/2000 21:46:49
* firstname.lastname@example.org, 2000-09-27, 17:05:53:
| I have a number of older Compaq Proliant boxes. These are p90s, and have
| a large compliment of nonstandard (non APIC stuff IIRC) components to
| support SMP (not to mention that standard pentiums don't support it "in
| house" either).
I don't recall at exactly which point the APIC/MPS machines appeared -
the initial multiprocessor Intel machines from Compaq were the
Systempro and Systempro XL.
The Systempro was an asymmetric dual processor system. The second
processor fielded only one interrupt - a kick from the primary
processor. This obviously meant that IO performance was not all that
it might be. Processors ranged from 386-25 through 486-66.
The Systempro XL was the first symmetric system, with two processors.
The second processor had an extra set of the standard (EISA) interrupt
controller(s). If a driver could support it, you could enable the
interrupt line on the second set of interrupt controllers and both
processors would receive the interrupt. Typically a particular piece
of hardware was configured to interrupt a particular processor
(`manual' interrupt load balancing !). The second processor also took
it's own clock interrupt (which you could stagger from the first). I
can't remember which processors were available, though it was unlikely
to be Pentium.
It may be that the first Proliants used a scheme similar to the XL (as
they went to four processors).
I lost touch after the MPS spec machines appeared.
The other set of machines which might be interesting are those based
on the Corollary (now owned by Intel) cbus. Some vendors (Mitac being
one) produced systems with up to 7 processors (7 * 386-16 in one
case). Digital also produced four processor (486) cbus systems.
Other oddities include the Apricot two processor machines (with MCA)
and four processor AST Manhattan systems (with a proprietary
It feels like a long time ago (around 6 years).