Some more information on the 1202 and 1201 alarms: http://www.hq.nasa.gov/alsj/a11/a11.1201-pa.html

tl;dr: Some misconfigured switches meant that rendezvous radar jobs kept being erroneously scheduled, which used up available memory. Whenever there was no more memory available, the alarm would fire and the computer was rebooted. It would immediately restart (resuming from near where they left off) all the high priority jobs (while not restarting the radar jobs), meaning that it could still land safely.

Jack Garman had hand-written down all the trouble codes on a "cheat sheet". He's the one who called "go". I am not even sure if the MIT software team knew what 1201 and 1202 were.

The AGC was one of the first to use priority multitasking. The 1201 and 1201 faults were indication that lower priority tasks were getting yanked.

See "Moon Machines". Seriously.

What would be an example of a lower-priority task in this situation?

A couple of links to the videos you mentioned:

http://www.sciencechannel.com/video-topics/space-videos/moon...

The above is probably one of the most informative 2 minute videos I've ever seen.

https://www.youtube.com/watch?v=DWcITjqZtpU&list=PL7E6922816...

"there were no specs, we made it up" "if you screwed up you got a stack of papers that was 2 feet thick" "the overall memory for the Apollo guidance computer was 72 kilobytes"

https://www.youtube.com/channel/UClDdlBdSzrWIUijnnUDXobw

https://www.youtube.com/channel/UCNpdHqZ5OmFOnICpZz4Mflw

Clicked into the first one and got a thing about the insulation between the tanks - the 3rd video in the playlist was about them hiring surfboard makers to do the honeycomb insulation between the fuel tanks, since they had more experience working with the materials in the heat conditions.

Just another kind of "the space program was amazing" thing - the sheer diversity of people who got hired on to contribute is continually surprising. An amazing tribute to the pragmatism of NASA under the conditions.

Oops - display and keypad. See above :)

Display and keypad as I recall.

The problem was actually a deployment problem. The checklist for configuring the computer left a diagnostic mode on that sucked up a lot of CPU.

This is definitely the best way to listen to the audio:

http://www.firstmenonthemoon.com/

this is amazing

And I thought zero-downtime web app deployments were stressful... this really puts stuff into perspective.

It's embarrassing that web apps have has much downtime as they do given the processing power they are given.

It actually makes sense given the economics of the situation: time invested in high availability is a poorer use of resources than, say, adding features for most web sites.

We can make web sites that stay up, always. It's just that it costs a lot more and / or they do less.

Oddly enough Google is throwing an error on that file.... to many people downloading the file recently.

I've rehosted it here:

http://share.rothamel.us/Apollo_11_Landing.mp3

Because there was no text chat then. BBN was contracted to build the first four IMP machines in 1969.

We put someone on the moon before we invented text-chat? Wow.

We put men on the moon before we invented the digital watch.

We put men on the moon before we put wheels on suitcases.

http://www.nytimes.com/2010/10/05/business/05road.html

Seeing as the computers were spitting error numbers instead of error messages, I am guessing that wasn't an option at that time with the hardware they had.