Weave your name into the Apollo computer
The Apollo Guidance Computer's programs were not saved to a disk. They were woven. A wire threaded through a magnetic core stored a 1, and a wire passing around it stored a 0. Type a name and see it as AGC words and rope.
Two 7-bit characters fit in each 15-bit AGC word. Words are shown in octal, as the programmers wrote them.
Weave the bits: 10 words against the clock
You get a target word in octal. Click the cores to send the wire through (1) or around (0) until your word matches. Each octal digit is three bits, so the cores are grouped in threes. Wrong submissions cost 5 seconds.
Best time: —
Rope complete
Software you could hold in your hands
Woven, not written
Rope was made by threading wires through or around rings of magnetic material. In the real modules each core was shared by many wires: with 192 wires through or around each core, a single core held 192 bits.
Weeks per module
Manufacturing a rope module was slow and expensive: about 8 weeks and around $15,000 each. Once the software was woven in, it could not be changed, so it had to be right.
The weavers
The rope was woven at Raytheon near Boston, largely by experienced women textile workers. Engineers nicknamed it "LOL" memory, for "little old ladies". The skill in their hands is a big part of why the code flew exactly as written.
36,864 words
The Block II AGC had 36,864 words of fixed (rope) memory and 2,048 words of erasable memory. The 7 core sets and 5 VAC areas that ran out during the 1202 alarms lived in that small erasable memory.
Why octal?
Each word had 15 data bits plus a parity bit. 15 bits split neatly into five groups of three, and each group of three is one octal digit (0–7). Alarm codes like 1202 are octal numbers too.
What this toy simplifies
Here each word gets its own wire through 15 cores, which makes the pattern easy to read. Real rope packed many words through each core. Your name is stored as plain 7-bit ASCII, which the AGC didn't use.