The computer that put Neil Armstrong on the moon (1960)

infolab.stanford.edu

39 points·raganwald··5 comments

"This is the type of computer that went to the moon in the Apollo missions from 1969 to 1972. There was one computer in the Lunar Excursion Module (LEM) and one the mothership (CM) circling above. It was the first use of integrated circuits, as still displayed in the timeline cabinet to the left. It's cycle time was 1 Mhz, 11 instructions. It had 1K of 16 bit words of erasable (RAM) core memory and 12K of read-only memory (ROM). The ROM held the "Colossus 249" flight control software. There were no disks or tapes in the flight system."

Some first person accounts from a SW engineering perspective from Peter Adler & Fred Martin - both from the MIT lab that developed the LM Guidance software.

http://www.history.nasa.gov/alsj/a11/a11.1201-pa.html http://www.history.nasa.gov/alsj/a11/a11.1201-fm.html

Check http://en.wikipedia.org/wiki/Apollo_Guidance_Computer for more information.

The strangest feature was its core rope memory. In order to save weight only the 1 bits had a core. Whenever a code change was made the memory had to be rewoven by hand by little old ladies, hence the name LOL memory.

This appears to be an earlier version, not the one that was used in the manned missions, the BLOCK II.

I worked for Decca Navigator in the 1970s. They had two ladies (not particularly little or old) who made read-only program memories for the Decca Omnitrac civil aircraft navigation computers. These had core arrays with the sense line hand-woven through the cores, going through a core or bypassing it depending on whether that bit should read as a 0 or a 1. They worked from printed charts referred to as 'knitting patterns'.

Much more information on the AGC at Wikipedia, including the instruction set: http://en.wikipedia.org/wiki/Apollo_guidance_computer

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