[Simh] Disk info request

[Johnny Billquist]

On 2016-03-09 17:10, Clem Cole wrote:

> Anyway, a few things changed... local caches were introduced on the
> drive, which mitigated a lot of what UNIX was doing because they did
> their own arm scheduling.   Plus drive manufacturing got better at
> packing sectors, so when before the max number of sec/cyl was a fixed
> amount, the larger drives now sec/cyl changed depending on the drive.
>   Much less the whole bad block stuff would screw up all the OS work.
> Finally,  SCSI introduce the idea of a single Logical disk block (i.e.
> the disk was just a linear array of blocks) and all the scheduling was
> left to the controller microcode (i.e. a dumb OS was better than one
> that tried to out smart the controller).

That is also the case with MSCP... Not sure if it predated SCSI, but for 
Unix systems, I suspect MSCP came before SCSI.
(And is the reason why I ask if VMS really try to figure out geometry 
for MSCP, since it don't really make much sense, or even can be done 
accurately, depending on the disk.)

	Johnny