Margaret Hamilton, NASA's lead developer for the Apollo program, standing next to all the code she wrote by hand that took humanity to the moon in 1969.
🇺🇸🇺🇦
@heydaave @rogward Fortran was used for simulation on mainframes, but the Apollo guidance computer software was hand-written assembly (as well as a second interpreted language run by a small interpreter in the AGC code, mostly for higher-math calculations that were tedious and error-prone to hand-code).
IIUC this is because compilers at the time couldn't output anything nearly as memory-efficient as hand-rolled logic and space was at an absolute premium on the AGC, since individual bits were stored via weaving metal cores together and so every bit translated directly into more weight on the mission and more time for the seamstresses doing the physical programming.
@mtomczak
I spent a lot of time with good old FORTRAN simulating train operations -not scheduling, actual dynamic wheel- rail interactions through curves under braking/pulling etc. Also individual car "rock and roll" on uneven track. I had jobs that ran 10+ hours to simulate a few minutes, swapping modules in and out of 32k memory on my pdp-11 for each iterative step.
@dbc3 That is so cool. I hear stories like this sometimes and my feelings are split down the middle between "I'm glad I don't have to deal with that level of detail" and "The era where machines were that explicit was kinda awesome." Barely anyone really understands how computers work these days (in the sense that even coding directly in assembly is coding atop two layers of abstraction, at least, from the dance of the electrons).
@mtomczak
I wrote graphics routines on my Apple II w/o an assembler, keying in hex instructions. I generated mesh data for finite element models, drew pictures to validate data, then displayed results of mainframe analysis with colored stress contours, animated deflections. This was before NASTRAN & ANSYS had any graphical display features.
I used those tools to, among other things, get AAR approval of the custom railcar to carry STS solid rocket boosters from Ala. to Fla.
#computasaurus
@mtomczak @rogward That's a nice history lesson, Mark. Thanks. I wasn't thinking about SWAP. It's a damned miracle we made it to the moon and back.