Post by @thalia@discuss.systems

2026-10-16 04:40 UTC

Throughout this process, I fixed about a dozen bugs in the original assembly program and many other small issues. It seems it was less tested than the assembler, my last porting project, which had impressively few bugs in its 3,583 lines of assembly. 6/6

Replies (1)

@thalia@discuss.systems 2026-10-24 21:48

You've heard of Y2K and the 2038 problem, but what about the 1975 problem? The UNIX form letter generator converts the current date to a string, but it only handles 1974. Why isn't it more general? Well, the form utility was written around 1971 when UNIX used a different unit for time, jiffies (60ths of a second) since the current year instead of seconds since 1970. This 60× precision caused times to overflow a signed 32-bit integer every 13.6 months, so the epoch was bumped yearly. This yearly ritual of modifying the kernel meant it wasn't worth generalizing to support any year. An earlier version of form uses jiffies since a 1972 epoch. The version from UNIX V4–V6 does the bare minimum to update it to the new system of seconds since 1970, while keeping the yearly overflow. #unix #retrocomputing #vintagecomputing

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