On Thu, 23 Aug 2018, Mikulas Patocka wrote: > PC hardware from 1980s and 1990s didn't handle back-to-back accesses > correctly and required i/o delays (accessing a dummy port 0x80 was a > common practice) - and I think that the Alpha Avanti chipset suffers from > the same problem. Avanti systems used the National 87312 or 87332 super-I/O chips, so it can be easily checked with the relevant datasheets. As I recall it was more like actual ISA multi-I/O cards that had such timing issues. Maciej