[Simh] Disk info request

[Clem Cole]

On Wed, Mar 9, 2016 at 11:16 AM, Johnny Billquist <bqt at softjar.se> wrote:

> I suspect MSCP came before SCSI.


I agree.   In DEC's case, support for MSCP certainly was first, but I
believe the protocols are contemporaries. NCR was a very early SCSI player,
but Western Digital, Shugart or someone like that might have driven it
originally (I've forgotten - I have some early SCSI docs at home, I
think).  I forget when I first saw it.


I do know NCR's SCSI 54C30 (and later the *C700) chip set became the de
facto standard  and they were early UNIX adopters.  Plus the aftermarket
folks were using "industry standard" interfaces on the drive side and just
replicating the Massbus or whatever on the host side for SW compliance.
 BSD Unix in particular was birthed using aftermarket I/O for cost reasons
 - i.e. most of the system we had a Berkeley (and other University sites)
had SI or Emulex controllers, not real DEC ones.     Ultrix inherited all
of the support from BSD, but the code was written by the CSRG folks in the
late 70's early 80's.

While using when DEC supported a technology works as a good first order
system and certainly for DEC developed ones, the bottom line is that SCSI
was on other systems that came from the rest of industry long before DEC
picked it up.  Thus we have to be careful dating things by using when DEC
brought out support.

Clem
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