On 2/1/22 15:40, Paul Koning via cctalk wrote:
On Feb 1, 2022, at 4:31 PM, Grant Taylor via cctalk <cctalk@classiccmp.org>
wrote:
On 2/1/22 11:23 AM, Paul Koning via cctalk wrote:
Did any DEC MSCP disks use it?
Please expand "MSCP". My brain is failing to do so at the moment.
Mass Storage Control Protocol, the geometry-independent storage access scheme
DEC created in the early 1980s. Early implementations include the HSC50 (for
VAXclusters) and the UDA50 (Unibus adapter), talking to disk drives such as the
RA80.
With MSCP, DEC switched to addressing disks by sector offset, as SCSI did
later, rather than by geometry (cylinder, track, sector)
All SCSI devices were logical block number, all the way back
to the original SASI (Shugart Associates System Interface).
I had a 10 MB Memorex Winchester drive with SASI adapter on
my Z-80 CP/M system in about 1981 or so. Maybe I
misunderstood your sentence above, what the "later" applied to.
Jon
