Booting an IBM MP 3000 S/390 System

Guy Sotomayor ggs at
Thu Aug 6 13:43:49 CDT 2015

On 8/6/15 11:05 AM, Eric Christopherson wrote:
> On Thu, Aug 6, 2015 at 12:41 PM, Guy Sotomayor <ggs at> wrote:
>> Back to the MP 3000.  There are a number of CPUs in the box.  Two are the
>> most
>> obvious: the SBC running OS/2 and the actual S/390 CPU.  However, there is
>> another
>> S/390 CPU in the box as well.  It is not visible (at least directly) to S/W.
>> It is responsible
>> for providing the high performance I/O capabilities (like native disk access
>> and making
>> them appear as conventional channel attached devices instead of RAID-5 SSA
>> drives).
>> The OS/2 SBC is there to emulate some of the slower devices (card
>> reader/punch,
>> direct attached 3270s, etc).
> So the OS/2 computer is actually a component of the mainframe's
> control processor, not a separate PC?
In various other S/390 and z/Series machines, there is a laptop that is 
the "service element" with
special S/W (now I think on Linux).  On the MP3000, it is a single board 
computer that is on what
looks like a big PCI card.  By it's nature it is hooked into various 
parts of the MP3000 system through
the various other things that sit on the PCI bus.  Note that the PCI bus 
is shared between the SBC
and the other parts of the MP3000.

If you don't fire up the system element software the OS/2 system would 
appear as a somewhat
"normal" PC with a bunch of special device drivers.

There's a great diagram (too complicated to reproduce in ASCII art) that 
illustrates all of the major
components in the MP3000.  It's located in the IBM Redbook "Multiprise 
3000 Technical Introduction".
It's Figure 1 on page 8 of the redbook.  This is a really great 
introduction on the MP3000.

TTFN - Guy

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