The origin of the phrases ATA and IDE [WAS:RE: formatting MFM drives on a IBM PC]

Alan Hightower alan at alanlee.org
Mon Oct 2 10:27:25 CDT 2017


 

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 
 


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