IBM 9331-011 8" External Floppy Drive - eBay 183038271095

Adrian Stoness tdk.knight at
Fri Feb 2 00:41:59 CST 2018

plc companies aka industrial companies do these weird things to force u to
buy their hardware and be locked in..........

ge faunic had their workmaster systems for interfacing into series one six
90/ series systems ect u could get away with a 5155 or a p70 as those were
what the workmaster 1 and 2 were built from but in black and cost 12-20k
new with software and interface card and or searial cable

as for the weird plc that did the floppies with that spacing do you
remember the manufacture sounds like something siemens would do god their
products suck they seem to be really good at going out buying good hardware
software and making them disappear

On Fri, Feb 2, 2018 at 12:17 AM, Chuck Guzis via cctalk <
cctalk at> wrote:

> On 02/01/2018 09:39 PM, Fred Cisin via cctalk wrote:
> > When I first got a Micropolis drive, I found "100tpi" hard to believe.
> > But, interchange attempts showed that by the inner tracks, it was not
> > 96tpi, and nor a multiple of 48tpi.
> > My homemade developer, and my patience to keep trying weren't good
> > enough to be able to successfully do other than take their word for how
> > many.
> > (Seeing the difference between 96tpi and 100tpi should be easier than
> > telling the difference between Leica thread (39mm x 26 Whitworth threads
> > per inch) V the early Russian Fed (39mm x 1.0m DIN thread)
> > some of the earliest Canon imitations (39mm x 24tpi thread))
> Other than a brief encounter with an SA400 (single-sided 48 tpi. 35
> cylinders), the Micropolis 100 tpi drives were my first real run in with
> 5.25" drives.
> Great drives, heavy, built like a tank--and expensive.  I've got a
> late-model 96 tpi Micropolis that illustrates their NIH mindset--the PCB
>  pivots as you close the door latch.  Still used the precision-ground
> leadscrew positioner.  Buffered seek; something like 4 steps per
> cylinder, if you can believe it.
> ISTR that if you stick a formatted 100 tpi ddisk in a 96 tpi drive and
> do a read ID, the first cylinder reads as 6.  That is, the 100 tpi disk
> is offset a bit more toward the outside of the disk.  You can read a few
> cylinders after that, before the misregistration causes things to get
> weird.
> --Chuck

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