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Mike Stewart here! I led the restoration of the AGC documented on CuriousMarc's channel and co-administrate VirtualAGC. There is a lot to unpack here. First: this is indeed a real …

For the communications project specifically (and also a couple of other projects we have going on), I combined the FPGA AGC and the Monitor into a single design that runs on a Digi…

The Command Module system test code Sundial includes a slightly earlier version of these same routines: https://github.com/thewonderidiot/sundiale/blob/master/sundi... This is a wo…

No, it's not. The 1 here is using interpretive index register X1 to index onto GAINBRAK. The star on the DMP means that multiplication is indexed. GAINBRAK is one of the pad-loaded…

People frequently seem to think this is about the line number it's on (666), but that doesn't have anything to do with it. That line number is a totally modern construction; the or…

That call to STOPRATE was there to zero out attitude rate commands at the moment the astronaut switches into the semimanual final descent program P66. It was removed in the final f…

These files were originally put on GitHub in the VirtualAGC repository [1] in 2015. The code was publicly released and digitized into these source files in 2009, through cooperatio…

Wherever we added modern comments, they are denoted by a double hashtag (##) at the beginning of the line. Everything else, minus formatting concerns, is directly from the original…

Don is still around, and is still awesome! His memory for events around that time is surprisingly sharp, for it being 50 years ago. He's been an invaluable resource for us at the V…

The Interpreter was written by Charley Muntz, not Margaret. Margaret wrote a large chunk of the DSKY display routines and a lot of the alarm/abort logic.

Nah, they put a couple of precautions in to make sure you couldn't put the computer into standby accidentally. First, software has to set a bit to enable standby mode to be entered…

Many years now of research and simulation of the system (I led the restoration of the computer mentioned in the article). There's not a single place where you can read everything, …

Solder is used extensively in satellites nowadays. The catch, though, is that you must use leaded solder, because the lead dramatically decreases the occurrence of tin whiskers. Ro…

Did it use wet tantalums, though? If the alternative is "solid tantalums", then it didn't -- SCD 1006755, the only type of tantalum used in the computer, specifies them as "Capacit…

Sadly most of what you read by googling these problems is misinformation. It was actually an incredibly sinister systems integration bug, that wasn't well described even at the tim…

To the contrary! In our AGC, all of the capacitors not tucked into cordwood holes sport a KEMET logo and part number: https://photos.app.goo.gl/oGsrgXBpNMccmkWV7 I think the Comput…

Yeah, it was absolutely incredible to see that clock being generated for the first time. That was the first module we powered up, since it's the easiest -- just give it 4V and 14V …

Yes, the current plan is to do a bit of an exhibition/tour with it. Details are still murky, since we still have a good bit of work to do to get it fully working.

Yeah, definitely. We took a ton of pictures and video. I'm not sure when they will be posted, since I'm sure there's a lot of editing to do.

Hey all, Mike here! I'll be more than happy to answer any questions about the project, the AGC we're restoring, or anything else!

I haven't used or prepared rope memory, but I have done quite a bit of research and planning to potentially construct some in the future. Using it wasn't terribly exciting; the rop…

Indeed! He has a fun anecdote on his website [1] about the throttle control routines, which he was responsible for. His account of it is worth reading, but long story short: The IC…

Yep, that's right -- Don was the guy who came up with that procedure.