On Wed, Dec 18, 2019 at 1:52 PM Paul McJones <paul@mcjones.org> wrote:

Computer History Museum curator Dag Spicer passed along a question from former CHM curator Alex Bochannek that I thought someone on this list might be able to answer. The paper "The M4 Macro Processor” by Kernighan and Ritchie says:

> The M4 macro processor is an extension of a macro processor called M3 which was written by D. M. Ritchie for the AP-3 minicomputer; M3 was in turn based on a macro processor implemented for [B. W. Kernighan and P. J. Plauger, Software Tools, Addison-Wesley, Inc., 1976].

Alex and Dag would like to learn more about this AP-3 minicomputer — can anyone help?

[I recommend that follow-ups go to coff, which is Cc'ed here]

I took a short stab at this, but can find little beyond references in the aforementioned M4 paper.

I did, however, run across this: https://www.cia.gov/library/readingroom/document/cia-rdp78b04770a000100110018-1

This appears to be a declassified letter written to the US Air Force at Bowling Green Air Force Base in regards to spare parts fo the AP-3 computer; dated October 19, 1966. The list of parts seem reasonable for a minicomputer, and it further seems reasonable to believe that this may be related to the same type of computer referenced in the M4 paper. However, details of the sending party have been redacted, and there is nothing pointing to the identity of the manufacturer.

Sadly, that's all that seems available. I wonder if, perhaps, Doug McIlroy (Cc'ed directly to float this to the top of his stack) can shed more light on the topic?

- Dan C.