IBM System/370 turns 50 years old

Jon Elson elson at
Tue Jun 30 18:38:17 CDT 2020

> On 30/06/2020 16:44, Kyle Owen via cctalk wrote:
>> Happy birthday to the 370! Looks like it was released to 
>> the press on 30
>> June 1970.
Well, actually, IBM released the first 370 in 1968, only 
they didn't want to tell anybody too soon.
So, they camouflaged it as a new 360 model, the /85, and 
only sold it to the (US) NSA, so nobody was going to get to 
see it for a while.

The 360/85 was a prototype of the 370/165, and they really 
didn't change much to make it the 370.
The /85 had 16-bit static RAM for a small writable control 
store and storage buffer (cache), as well as a read-only 
control store for the 360 instruction set.  The 370/168 
moved up to 64-bit static RAM chips, and the entire control 
store was writable.  They also changed the logic cabinet 
layout a bit.

The computer console was identical, as far as I can tell, 
although photos of the /85 are extremely rare.
The /85 was the first machine IBM delivered with the MST4 
monolithic logic chips, storage buffer, writable control 
store, water cooling, and probably a few other things.


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