On 2017-10-02 08:22, Jules Richardson via cctalk wrote:
> I mean, why SCSI wasn't used? It would have been an established standard by > then, the drive complexity seems comparable to IDE/ATA (i.e. intelligent > commands over a parallel bus), and SCSI controllers can be extremely simple - > just a handful of LS logic ICs - unless you want to add loads of command > queuing and such (again, comparable to IDE) The simple fact IDE is a single master to indexed slave only interaction vs a SCSI conversation where each ID must be both an initiator and respondent on a contentious shared bus separates the complexity quite a bit. PIO IDE controllers can be just a few bus buffers and an address decoder. PIO IDE slaves only have to decode a register address and synchronously return 16-bits at a time and only while selected by a simple strobe. -Alan
