Booting an IBM MP 3000 S/390 System

Eric Christopherson echristopherson at
Thu Aug 6 13:05:59 CDT 2015

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?

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