Baydel Unibus disk systems

[Mike Ross]

On Sat, Mar 19, 2016 at 9:41 PM, Christian Corti
<cc at informatik.uni-stuttgart.de> wrote:
> On Fri, 18 Mar 2016, Mike Ross wrote:
>>
>> I just have the controller board; I don't have any of the hard drives
>> left. All I remember is the disk was an 8" and the interface is a
>> single 40-pin cable; so not SMD and not SCSI. Far too early for IDE or
>> ATA. Any suggestions for what the interface might have been and what
>> disks might have been used? What hard disks were around in late 70s /
>> early 80s that used a single 40-pin connector??
>
>
> My guess is that it's not a controller board but just the interface to the
> controller found in the external enclosure, probably with the hard drive.
> The interface would implement things like NPR and BR and the like, so there
> wouldn't be enough board space to implement a complete hard drive
> controller, especially if the board dates from that era. IMO it's something
> like a RX211 board for hard drives.

Well you were right on the money! I found a manual for the thing. More
precisely I found I had a manual for the QBus version of the thing
squirreled away.

Baydel called the entire Qbus subsystem the 'Baydel D405' - and Google
returns precisely zero relevant hits for that search! I don't know
what they called the Unibus version. The host interface (Unibus or
Qbus) was indeed only half the system. Bayel referred to it as the
'I-board' (for 'interface'); it talked via the 40 pin connector to the
'P-board' (for 'personality') mounted in the drive chassis; the
P-board did indeed implement the drive controller functions. The drive
was a Pertec D8000 20MB Winchester; the drive chassis could contain
one of these (which all my systems did) or two of these (which needed
a special handler for the OS) or one 20MB hard disk plus one Shugart
8" floppy - which emulated an RX02.

That all rings bells with what I had.

Doesn't help much as the chances of me finding such a subsystem are
tending to zero I suspect. But mystery solved!

Thanks

Mike

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