The BBC has put together a great back story on the building and programming of the computer aboard Apollo 11 that guided and controlled the trip to and from the moon. The video interviews are amazing as is the entire story.
Programming the computer, doing navigation with the sextant, and wrapping the “rope cores.” Gad. It was an amazing feat but given this piece of the technology it was even more amazing. Building an iPhone app looks like child’s play compared to this stuff.
However, the entire computer was not so hi-tech. In order to make sure that the software was robust it was “woven” into so-called “rope core memories”.
These used copper wires threaded through or around tiny magnetic cores to produce the ones and zeroes of binary code at the heart of the software.
Pass the copper wire through the core and the computer read it as a one. Pass it around and it was read as a zero.
“Once you get it wired it’s not going to change without breaking those wires,” said Mr Hall. The rope core memories would become know as “LOL memory” after the “little old ladies” who knitted together the software at a factory just outside Boston.
These ladies would sit in pairs with a memory unit between them, threading metres and metres of slender copper wires through and around the cores.