On 02/09/2018 12:26 PM, allison via cctalk wrote: > IBM PC early also did that... other vendors of the 8088 didn't work > in the 64K and early 256K IBM PCs due to a slight timing variation > that reputedly intel helped design in. One gate fixed it but it was > undocumented thing you could getaway with only with Intel 8088s.
Hmm, must have been *very* early PCs, as mine had an AMD 8088 in it--but wasn't AMD a licensee of the Intel part? But then, so was NEC. I think IMSAI used the "different" NEC 8080s in their floppy controller, as they were inexpensive (because of the incompatibility) and in the particular application, it didn't matter. I do recall very early 8085s having a "reset" bug, necessitating some external glue, but it's been too long for me to remember the details. --Chuck