Via @mountain_ghosts via The Register
One of the reason planes and vehicles in general are so reliable and safe is because all of the components are supposed to be rigorously tested until all failure modes can be accounted for and work around a found.
Now Boeing has had some oopsies with their angle of attack indicators back in ~2016, but those were new parts that’s clearly didn’t get tested enough.
This computer is likely an old design and it’s kept that way because we know how it fails, can predict those failures and know how to respond to them. Switching to a newer flight computer with a 64bit architecture would allow for storage of longer numbers, but it would also mean that every line of every bit of software that touches that computer would have to be gone over and tested with a fine toothed comb before any plane with the new computer would be allowed to fly again.
It’s much cheaper and safer to use an already known design and just work within its limits.