I have recently been assigned to work on project that uses a lot of communication based on files, file watchers etc. This is a pattern that seems very old to me and I want to ask about it (of course, in a way that can be answered SE format).
Is such a question on-topic on Retrocomputing.SE?
In general, I think so.
However, the specific example you cited seems a lot like the UNIX "everything is a file" philosophy applied to application code. This feels timeless to me, so I'm not going to be a good judge of whether it should be on-topic.
I'll agree with Wizzwizz4 on this. While in general it may - like most stuff - be on-topic, design patterns aren't anything that gets out of date - heck, most punch card algorithms are still a thing - so it is quite border line, and may rather belong to generic Stack Overflow.
The only case I can think of, that may fit without any doubt is, if it's about details of working on an old, no longer maintained OS/runtime and not supported in modern versions/offsprings.
Let me think of a design pattern (or at least something close) that I'd consider on-topic....
"Mix, match, sort and filter" tape files (like handled in N. Wirth's "Algorithms and data structures" probably fits - That's a pattern that only very rarely shows up these days and is at risk of being lost in history, because the problems (trading algrithm efficiency for fewer tape runs and changes) encountered there are simply no longer existing.
Generally, "patterns" (rather: habits) that were applied back then quite frequently (and often, with reason) would definitely rather fall into the category of an anti-pattern (and, thus, in real danger of complete extinction) these days, like (I'm exaggregating a bit in the following)
Apart from such examples, I can relly not think of "real Design Patterns" (as in the Gang of Four book) that would fit here and not way better in other places.
