On 10/2/17 5:22 AM, Jules Richardson via cctech wrote:
On 10/02/2017 01:46 AM, Alan Perry via cctech wrote:
There was a call to form the CAM (Common Access Method) Committee of
X3T9.2
(SCSI-2) on 30 Sept 1988 and they first met on 19 Oct 1988. The primary
goal was to come up with a SCSI subset to facilitate it support in
multiple
OSs and BIOS on PCs. At the first meeting, two items mentioned in the
minutes seem relevant. 1. Jim McGrath of Quantum was interested in
embedding SCSI in the drive without a physical SCSI bus and described
problems with reference to the PC/AT.
Does anyone know why IDE/ATA even came about? 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)
Did it simply come down to pressure from vendors, wanting to
distinguish between expensive workstation-class drives and something
cheaper which could be associated with the lowly PC?
Here is a complete quote from the minutes:
"Jim McGrath of Quantum defined his company's interest as being
primarily in the ability to embed SCSI into a drive without there being
a physical SCSI bus present. He described some problems of this
environment, with references to the PC AT bus in particular. Jim
believes that the greatest benefit of the CAM will come from a "severe
pruning of SCSI functionality in order to meet the goal of a precise,
simple, software interface."
alan
cheers
Jules
