Well they weren’t running a Windows program, or it would have “crashed”, there was an error in the checklist, a switch in the wrong position, that confused the radar system or somesuch, that’s why the 1202 errors.
But the system just prioritized and kept on keeping on. We can talk about how primitive the hardware was, but the computer code they wrote to run was pretty tight. This was done under contract by MIT, at the Draper laboratory. Charles Draper was one of those once in a lifetime kind of special geniuses, he’d cut his teeth on sophisticated wartime aircraft navigational instruments so he was a natural to get heavily involved in Apollo.
Parts of the software program were actually hard wired into the spacecraft itself, as “core memory”, custom tailored and specifically wired for each unique mission. Tiny wire loops around an iron core, bazillions of them, each representing bits and bytes, 1s and 0s, made by the nice ladies at Raytheon or wherever. There’s a pretty good YouTube video transcription of period NASA films showing the process, it was amazingly labor intensive and time consuming.
I worked all that stuff in missile guidance systems and know it very well. Had to learn how they were designed so I could fix them when needed.