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Apollo program source code

ibiblio.org

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Re: Apollo program source code

#41

Post by polyfractal »

samstave wrote: post #36
GnarfGnarf wrote: post #6

Earlier quoted context omitted.

"Core" memory is resistant to cosmic rays. The state of a core bit will not change when bombarded by radiation in Outer Space. Can't say the same of solid state memory. I worked on core memory computers in the 60's. You had 16K, tape drives (no disks) and FORTRAN. What a gas!

Just curious how they knew this given how young the computing industry was at the time that this was used. Were there some "Well, that's interesting..." moments where we launched something and realized it was affected by cosmic rays?

I think it's just an understanding of how the underlying physics work. Alpha and beta radiation will cause bits to flip in solid-state devices, because the state is held with electrons. Whereas core rope memory stores that state as magnetic fields in ferrite cylinders. So radiation will basically just bounce right off the giant ferrite cores (giant relative to solid-state semiconductors, that is).

*I am not a physicist, someone correct me if I'm grossly wrong.

Re: Apollo program source code

#42

Post by brendn »

samstave wrote: post #36
GnarfGnarf wrote: post #6

Earlier quoted context omitted.

"Core" memory is resistant to cosmic rays. The state of a core bit will not change when bombarded by radiation in Outer Space. Can't say the same of solid state memory. I worked on core memory computers in the 60's. You had 16K, tape drives (no disks) and FORTRAN. What a gas!

Just curious how they knew this given how young the computing industry was at the time that this was used. Were there some "Well, that's interesting..." moments where we launched something and realized it was affected by cosmic rays?

My guess is that radiation's effects on solid-state technology was well-known from nuclear tests.

Re: Apollo program source code

#43

Post by maaku »

Create wrote: post #18
Retric wrote: post #11

Earlier quoted context omitted.

At a low level your correct, but you can use error correction and a lot of redundancy to prevent cosmic rays from corrupting solid state memory and still have a lot more than 16K of storage space for a long time.

...and radhard designs.

...which involve error correction and a lot of redundancy. But I assume you meant radhard electronics boxes, which lets you run whatever you want within a cosmic-ray shielded box.

Re: Apollo program source code

#44

Post by kabdib »

samstave wrote: post #36
GnarfGnarf wrote: post #6

Earlier quoted context omitted.

"Core" memory is resistant to cosmic rays. The state of a core bit will not change when bombarded by radiation in Outer Space. Can't say the same of solid state memory. I worked on core memory computers in the 60's. You had 16K, tape drives (no disks) and FORTRAN. What a gas!

Just curious how they knew this given how young the computing industry was at the time that this was used. Were there some "Well, that's interesting..." moments where we launched something and realized it was affected by cosmic rays?

Hubble, the ISS and other low-orbit satellites are affected by the South Atlantic Anamoly, which funnels down charged particles from the Van Allen belts.

(This /was/ a surprise to the folks who designed Hubble, but the spook satellite people apparently knew all about it . . . and didn't tell the Hubble folks, not even over beer or something. Great win for national security, guys ).

Re: Apollo program source code

#45

Post by charlieok »

andrewcooke wrote: post #4

hmmm. so the "bugger words" at the end of, for example, http://www.ibiblio.org/apollo/listings/Colossus249/MAIN.agc.... are checksums - see http://books.google.cl/books?id=3fKzL0HfJp4C&pg=PA232&#3... anyone know the etymology? is it just a shortened form of "debugger"? is "bugger" not common slang in american english? or is this a joke?

I'm pretty sure it's a reference to Ender's Game. Also, the fact that Ender's Game was published in 1985 is of no import whatsoever.

Re: Apollo program source code

#47

Post by Create »

maaku wrote: post #43
Create wrote: post #18

Earlier quoted context omitted.

...and radhard designs.

...which involve error correction and a lot of redundancy. But I assume you meant radhard electronics boxes, which lets you run whatever you want within a cosmic-ray shielded box.

you can do more than just improve on the boxing

https://en.wikipedia.org/wiki/Rad-hard#Radiation-hardening_t...

Re: Apollo program source code

#48

Post by AsylumWarden »

strangetimes wrote: post #12
exDM69 wrote: post #3

Fun fact: the actual programs in the spacecraft were stored in core rope memory, an ancient memory technology made by (literally) weaving a fabric/rope, where the bits were physical rings of ferrite material. http://en.wikipedia.org/wiki/Core_rope_memory

"Some programmers nicknamed the finished product LOL memory, for Little Old Lady memory." LOL.

Great! Texting LOL to my grandmother suddenly has a whole new meaning. I love it! She often complains her memory is getting old so it works even better!

Re: Apollo program source code

#49

Post by AsylumWarden »

Nate75Sanders wrote: post #5
andrewcooke wrote: post #4

hmmm. so the "bugger words" at the end of, for example, http://www.ibiblio.org/apollo/listings/Colossus249/MAIN.agc.... are checksums - see http://books.google.cl/books?id=3fKzL0HfJp4C&pg=PA232&#3... anyone know the etymology? is it just a shortened form of "debugger"? is "bugger" not common slang in american english? or is this a joke?

Bugger is not common slang in American English. You can find people who will argue about that, but they don't get out much.

I've used bugger since the first of the Austin Powers movies. My friends and I used it until one of them married a South African girl and she made us stop being as it was incredibly impolite and rude apparently. I started again last year after watching Top Gear and then recently got yelled at by a new accounting manager who moved into the office across from my cubicle. Once again, I was being crude but in all honesty, for me, the word is no different than saying frag, frell, crude bunnies, etc.
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