HP drives

Chris Elmquist chrise at pobox.com
Tue Dec 28 19:13:01 CST 2010

On Tuesday (12/28/2010 at 02:45PM -0700), Eric Smith wrote:
> Tony Duell wrote:
>> Howeer, was there ever a 70 cylinder 5.25" drive? That is one that was
>> only designed to use 70 cylinders ? I mean a raw drive, not a
>> drive+controller like the HP units we're discussing.
> I haven't heard of one, though Micropolis made 77-track 5.25" drives  
> with 100tpi (vs. 35 or 40 track at 48tpi and 80 track at 96tpi), and a  
> few other vendors offered compatible drives, e.g. the Tandon TM100-4M,  
> where the "M" designates it as a 100tpi model.

Yes...  I can confirm these facts as I have two of each of those 100tpi
drives here and they connect to a Micropolis designed controller which
served as a reference design for that floppy subsystem.  Vector Graphic
deployed it in one of their early floppy based systems as well.

Chris Elmquist

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