Jay Jaeger cube1 at
Thu Aug 26 14:46:57 CDT 2021

On 8/25/2021 3:57 PM, Fred Cisin via cctalk wrote:
> On Wed, 25 Aug 2021, Jay Jaeger via cctalk wrote:
>> I don't have that code, however a couple of points:
>> First of all, I think Vector Graphic actually used Micropolis drives 
>> (and I suspect yours are because of the hard sectoring).  I have 
>> Micropolis drives on my Altair.  Back in 2006 I imaged my floppies - 
>> by reading the sectors on my Altair and transferring the data over to 
>> my PC and saving an image file.
>> Note that at least for the 100 TPI Mod II model you'd have to use an 
>> actual Micropolis drive or the tracks won't line up.  I don't know if 
>> that is also true of the Mod I drives which have a more standard 
>> tracks per inch.
> Important points!
> Yes, Vector Graphics was 100tpi.  That was not the only unusual aspect 
> to their format.
> Yes, Micropolis ALSO made 48tpi single sided drives.  I don't remember 
> whether they were 35 track or 40 track; I used one for years on a TRS80 
> (which wass 35 track); it was an exceptionally reliable, albeit heavy 
> and slow-steppping drive.

35 track. The aforementioned "Mod I" models.

> For 100tpi, there also existed Tandon TM100-4M drives.  The M stood for 
> "Micropolis".   One of the TM100-4M drives that I had did not have the 
> 'M' on the label.
> -- 
> Grumpy Ol' Fred             cisin at


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