agc2A number of years ago I read a contractor’s report about Computers In Spaceflight.  It was fascinating to me to understand just how much went into this one facet of space programs, and just how little computing power it took.  Any college student familiar with basic electronics can understand the fundamentals of these early computers, but the true magic was what the programmers did to squeeze so much out of such a “small” package.  Now it’s easier for us to have one of our very own thanks to one man’s hard work.

agc3John Pultorak spent close to $3000 and ten hours a week over four years to make ~15,000 connections between ~500 chips to build his AGC clone.  Then he documented it all in this exquisite 9 volume set of documents.  Even better, he’s released his information into the public domain to save others from having to do all the research and development themselves.agc1

Like many of these niche interests, there’s a group of enthusiasts who can help you with your version.

John has documented his project in 9 separate pdf files:

  • Part 1 – Overview [8.1 MB]: Introduces the project.
  • Part 2 – CTL Module [9.9 MB]: Design and construction of the control module.
  • Part 3 – PROC Module [6.7 MB]: Design and construction of the processing (CPU) module.
  • Part 4 – MEM Module [6.8 MB]: Design and construction of the memory module.
  • Part 5 – IO Module [7.0 MB]: Design and construction of the diskplay/keyboard (DSKY) module.
  • Part 6 – Assembler [0.5 MB]: A cross-assembler for AGC software development.
  • Part 7 – C++ Simulator [5.2 MB]: A low-level simulator that runs assembled AGC code.
  • Part 8 – Flight Software [2.8 MB]: My translation of portions of the COLOSSUS 249 flight software.
  • Part 9 – Test & Checkout [0.9 MB]: A suite of test programs in AGC assembly language.