> I would posit that Distributed systems are typically a category of concurrent systems Absolutely, and so are interactive systems, which are distributed/concu

> I would posit that Distributed systems are typically a category of concurrent systems Absolutely, and so are interactive systems, which are distributed/concurrent between the computer and the human user. In TLA+ all of these are described in the same way, but colloquially, engineers think of them differently, and there are actually good reasons for that, too. E.g. virtually no concurrent algorithms (for a single computer) account for a failure of a single core and its associated L1 cache, but all distributed algorithms do.