360/50 microcode listing

Ian S. King isking at uw.edu
Thu May 7 16:29:26 CDT 2015


I got a 360/20 "running" at LCM, but we didn't have the 2560 MFCM
reader/punch for which it was wired.  Unlike other 360s, the /20 didn't use
the channel architecture - all peripheral interfaces were built into the
2020 box.

And the machine won't even process instructions without peripherals being
sensed.  The printer and reader/punch are purely electromechanical, and all
electronics is in the interface, including such niceties as cover
interlocks and card-bin status.  Every macro-instruction cycle, the
microcode checks for those things and would stall if they were not in

I always wanted to emulate the MFCM, but there were always other
projects... and even with the ALDs, it was a sizeable challenge.

On Thu, May 7, 2015 at 12:15 PM, Chuck Guzis <cclist at sydex.com> wrote:

> On 05/07/2015 11:56 AM, Robert Ferguson wrote:
>> Is there a reliable estimate of the number of extant relatively complete
>> and/or actually working System/360 machines? A registry, perhaps?
>> I would find that to be a very interesting data point.
> I'd be interested also, in that a simple 360 CPU is essentially useless.
> You need at least a minimum collection of working peripherals to be able to
> do anything at all.
> --Chuck

Ian S. King, MSIS, MSCS, Ph.D. Candidate
The Information School <http://ischool.uw.edu>

Archivist, Voices From the Rwanda Tribunal <http://tribunalvoices.org>
Value Sensitive Design Research Lab <http://vsdesign.org>

University of Washington

There is an old Vulcan saying: "Only Nixon could go to China."

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