On the 370165 and the 36085

As noted in my post "The Case of the Bashful Computer", I found that the IBM System-360 Model 85 computer had the same type of double projection console as was found on the IBM System-370 Model 165, thanks to an advertisement at the time of introduction that appeared in the March 1968 Datamation.

In the book "IBM's 360 and Early 370 Systems", a copy of which I had the incredible good fortune of purchasing in a thrift shop, it was noted that "a cost-reduced version" of the 360-85 was the 370 that was furthest ahead in design. Given the front panel similarity, I suspect that this was what later became the 370-165, but the book doesn't say.

The book Microprogramming: Principles and Practices by Samir S. Husson gives the microcode formats for the IBM System-360 Model 40 and Model 50. Documents on Al Kossow's web site give the microcode format for the Model 30; this was also discussed in Bell and Newell, in an excerpt from a paper on a microprogrammed implementation of EULER on a 360-30 reprinted there.

A table in the book by Husson gives the microcode word length for other models of the 360 as well:

Model 20: 60 bit word... with one 16-bit microinstruction and two 22-bit microinstructions; one instruction is selected to execute from those three

Model 25: 16 bits Model 30: 50 bits Model 40: 56 bits Model 50: 88 bits Model 65: 100 bits Model 85: 108 bits

In a web search, I have been able to find out that the 370-145 had a 32 bit long microinstruction.

Would anyone here happen to know if the 370-165 and 370-168 did, in fact, have a 108-bit microinstruction word similar to that of the Model 85?

John Savard Usenet Zone Free Binaries Usenet Server More than 140,000 groups Unlimited download