360/50 microcode listing

Jon Elson elson at pico-systems.com
Thu May 7 21:05:16 CDT 2015

On 05/07/2015 01:07 PM, Dave G4UGM wrote:
>> -----Original Message-----
>> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Jon Elson
>> Sent: 07 May 2015 18:17
>> To: General at classiccmp.org; Discussion at classiccmp.org:On-Topic and Off-
>> Topic Posts
>> Subject: Re: 360/50 microcode listing
>> On 03/13/2015 01:32 PM, Al Kossow wrote:
>>> CHM was able to obtain volumes 18-20 of the IBM 2050 drawings, which
>>> are the microcode charts and ROS dump. I got them scanned and uploaded
>>> yesterday to http://bitsavers.org/pdf/ibm/360/fe/2050
>>> This was one of the things that I had been trying to locate for a
>>> while now.
>> Just a curious thing I've noticed.  Given the historic significance, and the large
>> number of machines produced, I'm kind of amazed at the incredibly small
>> number of 360's that apparently exist.
>> Yes, I know, any would-be collector could drag home a PDP-8 and put it in his
>> garage, even a whole rack mount system with an RK02 (or 3), dectape and
>> paper tape reader, and still get his car in the garage.  And, the system could
>> be run off normal mains power.
>> You can't do that with a real 360 (some 360/20's were pretty small), even a
>> 360/30 was a pretty big box.  And, you can't run a 360 off normal residential
>> power, either.  Many of the peripherals used 3-phase motors, and hacking
>> the converter/inverter to run off single phase would not be a task for any but
>> the most experienced EE.
>> But, it sure is a shame that there appear to be a tiny number of machines in
>> existence.  One list shows 15 or 16 machines, excluding the model 20.
>> Probably there are a couple more hidden somewhere, like the B1900 that
>> came to light so recently.
>> As fas as I can tell, NONE of these systems is complete enough to ever run,
>> with the possible exception of the
>> 360/30 at the CHM, which does seem to have a complement of peripherals,
>> and maybe control units, too.
>> Given the number of DEC 10's that are actually up and running, this seems a
>> bit of a surprise.  there might be some emotional attachments that are
>> behind this disparity.
>> Anybody have some comments?
> I think that you are not comparing like with like. How many KA10's are there left as that’s the DEC System/10 that’s comparable with the S/360. If you want to compare IBM Mainframes with DEC System/10 then you need to include S/360, S/370 and 43xx boxes. Now there may be few S/360's but there are 370's and I am sure there are many 43xx boxes.
> However I think that the quantity of preserved mainframes is dire when compared with other items of "technology" history. There are hundreds of preserved static steam engines, steam locomotives, vintage ,  veteran and classic cars or automobiles (not that vintage and veteran have specific definitions in relation to cars/automobiles), radios and TVs etc. I am sure there are more concorde aeroplanes and possibly even space shuttles than there are S/360's...
Well, I'm pretty sure that the Concordes have been 100% 
preserved, other than the one that crashed.  True also for 
the shuttles.

But, no, there is a list of known/suspected/rumored 360's, 
and it lists 15 or 16 "real" 360 processors (I'm excluding 
the 360/20, of which they list 5 units.)

There are several KA10's RUNNING!  Compared to how many of 
those were built, there seem to be a LOT higher percentage 
of those still extant than of the 360's.  (Maybe a bunch are 
still to be revealed, I suppose.)  And, I'm pretty sure 
there are NO 360's running.  The LCM is trying to get a 
360/20 running.  Maybe they are going to start with a small 
project before attempting something harder.


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