TRS-80 Model II

From: Joe <rigdonj_at_intellistar.net>
Date: Wed Feb 25 15:59:53 1998

At 08:30 AM 2/25/98 -0600, you wrote:
>You know, I have a WD-1000-XX controller that supposedly can talk to
>these drives. It also can talk to 5.25" drives.
>
>These controllers are SASI on the 'other' end (I think).
>
>Hmmm. I don't see many SA-1000's being offered for sale . ..
>
>Jeff

   I don't know if they're SA-1000s or what but I have two 8" DDs out of a
Tektronix piece of gear. I haven't had time to fool with them so i don't
even know how many contacts there are in the connector but they use AC motors.

   Joe

>
>> > Those are 8.4MB drives. Not SCSI, not even ST-506. Those are 8"
>> > Shugart mechanisms in there, 4 heads by 256 cylinders. I forget
>> > how termination worked in those units (haven't seen one in action
>> > in at least 12 years). And yes, the write protect switch and the
>>
>> Probably an SA1000 type interface. It's similar-ish to an ST506 interface
>> in that there's a control cable that goes to all the drives and a
>> separate data cable from each drive to the controller.
>>
>> The control cable has 50 wires, and is sort-of 8" floppy drive like. In
>> fact you can have a mixture of 8" SA800 floppy drives and SA1000
>> winchesters on the same control cable (up to 4 drives total). The data
>> cables were only used on the hard drives, of course.
>>
>> You terminate the control cable at the last drive (furthest from the
>> controller). The data rate is 4.34Mbps.
>>
>> Here's a pinout od the control cable. All odd numbers are ground...
>>
>> 2 Reduce Write Current*
>> 4 Head Sel 2*
>> 8 Seek Complete*
>> 14 Head Sel 0*
>> 16 Sector Pulse*
>> 18 Head Sel 1*
>> 20 Index Pulse*
>> 22 Ready*
>> 26 DS1*
>> 28 DS2*
>> 30 DS3*
>> 32 DS4*
>> 34 Step direction (low = in)
>> 36 Step Pulse*
>> 40 Write Gate*
>> 42 Track 00*
>> 44 Write Fault
>>
>> Rest not used.
>>
>> The data cable has the same pinout as an ST506 data cable, apart from an
>> extra clock from the controller to the drive on pins 9 (+ve) and 10
>> (-ve).
>>
>> > Ward Griffiths
>>
>> -tony
>>
>>
>
>
Received on Wed Feb 25 1998 - 15:59:53 GMT