Tuesday, Aug 29, 2006 at 22:39
Spot on Geoff :)
There are sites on the net that contain all of the assembly & microcode from every mission - including the most complex of all - the "J" mission that was Apollo 17.
Incredible stuff to see it all run in only kilobyte chunks of contextual, dynamically loaded code. They just don't have to be that clever these days, and sloppy code is OK because it can be.
The Apollo Guidance Computer (AGc) - brilliant stuff:
Off WIKI:
The Apollo flight computer was the first to use integrated circuits (ICs).
The Block I version used 4,100 ICs, each containing a single 3-input NOR logic
gate. The later Block II version used dual 3-input NOR gates in a flat-pack; approximately 5,600 gates in all. The gates were made using resistor-transistor logic (RTL). They were interconnected by a technique called wire wrap, in which the circuits are pushed into sockets, the sockets have square posts, and wire is wrapped around the posts. The edges of the posts bite the wire with tons of pressure per square inch, causing gas-tight connections that are more reliable than soldered PC boards. The wiring was then embedded in cast epoxy plastic. The decision to use a single IC design throughout the AGC avoided problems that plagued another early IC computer design, the Minuteman II guidance computer.
The computer's RAM was magnetic core memory (4K words) and ROM was implemented as core rope memory (32K words). Both had cycle times of 12 microseconds. The memory word length was 16 bits; 15 bits of data and 1 odd-parity bit. The CPU-internal 16-bit word format was 14 bits of data, 1 overflow bit, and 1
sign bit (one's complement representation).
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