4 ms·

I could be wrong. But I think part of why they did it this way was so they could edit things on the fly if a emergency dictated so. Having to ship a compiler (w

I could be wrong. But I think part of why they did it this way was so they could edit things on the fly if a emergency dictated so. Having to ship a compiler (would have likely been an entire separate computer) would have not been feasible. With things done this way and documented this why they could (fairly sure did) have the pages printed out on paper and such. And if say there was some bug or new routine that needed to be added mid flight they could go to a key board input (no screen) and with the instructions from the ground reprogram a section or add a new jump point or change a value mid flight. Remember, computers were not what they are today. They did not have super powerful laptops and such with fancy tools.

datenwolf 10y ago
> I could be wrong. But I think part of why they did it this way was so they could edit things on the fly The AGC code was stored in ROM. Notably a specific kind of ROM called "rope memory".
- nameless912 10y ago
  Hey, uh, Apollo <n for n > 10 and n < 18>? This is Houston. Could you pull out the ROM banks and flip a couple of bits for us? we made a mistake or two. All you need are some wire cutters and a very steady hand.
- mbrumlow 10y ago
  "The bulk of the software was on read-only rope memory and thus couldn't be changed in operation, but some key parts of the software were stored in standard read-write magnetic-core memory and could be overwritten by the astronauts using the DSKY interface, as was done on Apollo 14." Seams you were mostly right about not being able to change it. I was only somewhat right because I assumed it would all be editable. I over estimated the technology they had back then. I would gather from that there was for more fixed code than editable. Source: https://en.wikipedia.org/wiki/Apollo_Guidance_Computer https://en.wikipedia.org/wiki/Apollo_Guidance_Computer
  - datenwolf 10y ago
    > "The bulk of the software was on read-only rope memory and thus couldn't be changed in operation, but some key parts of the software were stored in standard read-write magnetic-core memory and could be overwritten by the astronauts using the DSKY interface, as was done on Apollo 14." Ah, yes right, there was something. I've been fascinated by the AGC by some time¹, yet I completely forget about that. Time to hunt down the mission protocols to understand what this patch did. ------ 1: … and the LVDC, which is the computer that controlled the Saturn-V. Because it was based on the computers used in ICBMs still a lot of information about that is classified. A lot of people conjectured that it was a IBM System 360 reshaped, but when actual LVDS board got torn down by electronics nerds over the past couple of years some significant differences to the 360 were discovered.

datenwolf 10y ago

> I could be wrong. But I think part of why they did it this way was so they could edit things on the fly The AGC code was stored in ROM. Notably a specific kind of ROM called "rope memory".

nameless912 10y ago
Hey, uh, Apollo <n for n > 10 and n < 18>? This is Houston. Could you pull out the ROM banks and flip a couple of bits for us? we made a mistake or two. All you need are some wire cutters and a very steady hand.
mbrumlow 10y ago
"The bulk of the software was on read-only rope memory and thus couldn't be changed in operation, but some key parts of the software were stored in standard read-write magnetic-core memory and could be overwritten by the astronauts using the DSKY interface, as was done on Apollo 14." Seams you were mostly right about not being able to change it. I was only somewhat right because I assumed it would all be editable. I over estimated the technology they had back then. I would gather from that there was for more fixed code than editable. Source: https://en.wikipedia.org/wiki/Apollo_Guidance_Computer https://en.wikipedia.org/wiki/Apollo_Guidance_Computer
- datenwolf 10y ago
  > "The bulk of the software was on read-only rope memory and thus couldn't be changed in operation, but some key parts of the software were stored in standard read-write magnetic-core memory and could be overwritten by the astronauts using the DSKY interface, as was done on Apollo 14." Ah, yes right, there was something. I've been fascinated by the AGC by some time¹, yet I completely forget about that. Time to hunt down the mission protocols to understand what this patch did. ------ 1: … and the LVDC, which is the computer that controlled the Saturn-V. Because it was based on the computers used in ICBMs still a lot of information about that is classified. A lot of people conjectured that it was a IBM System 360 reshaped, but when actual LVDS board got torn down by electronics nerds over the past couple of years some significant differences to the 360 were discovered.