-----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...
Dave
G4UGM