A cool vintage hardware hack.

From: Bob Shannon <bshannon_at_tiac.net>
Date: Sun Feb 2 09:27:01 2003

Not a chance.

Take a look at the interface schematics for the 13037 (interface) versus
the 12821A. There is near-zero doubt that
these need totally different drivers, as MAC disks make a good deal of
lower-level information
available to the controller than CS/80 does.

CS/80 drives use a logical block address very much like a modern ATA
drive. The MAC interface sees
the drive as raw sectors, tracks and surfaces.

It may be that by adding the HPIB option to the MAC controller that some
firmware translation takes place
that tries to make the 'H' series drive look just like a MAC drive, but
from looking at some RTE manuals it
seems that 'H' series drives were supported on the 12821A, at least by
the standard drivers. I guess what we
really need to know here, is did HP support 'H' series drives on a 13037
with the same driver as MAC drives.
 From what I've read of the 'MAC to H-series upgrade' program, this was
not the case.

I do know that at one point HP wanted all their MAC disk users to
'upgrade' to 'H' series disks, but the user
community did not like this 'upgrade' path due to the loss of
performance and system reconfiguration issues. HP's response seems to
be the adoption of CS/80 and the 12821A which on paper had a slightly
higher data transfer
rate than MAC disks.

I would have expected any drive on a 13037 to look, well, like a 13037
drive, but I'm getting a very different
impression from the RTE documentation and user community publications.

Hopefully I'm wrong here, I do realize it would make life easier for you
if I am.


Eric Smith wrote:

>Bob Shannon wrote:
>
>>I would think the CPU would have to use totally different drivers.
>>
>>Talking to the 12821A interface is TOTALLY different than talking to the
>> 13037 interface board from
>>the I/O backplane perspective.
>>
>
>I know that. I was asking whether they'd look the same to the computer if
>they were both plugged onto a 13037. I suspect the answer is yes, because
>all drives plugged onto a 13037 probably look to the host like MAC drives
>even if the 13037-to-drive interface is actually HPIB. Part of the point
>of the 13037 MAC controller was to provide some measure of device-
>independence.
Received on Sun Feb 02 2003 - 09:27:01 GMT