Pinout for SED9421

[Fred Cisin]

On Fri, 25 Nov 2005, Allison wrote:
> >>The all time worst was the 1771 internal data sep.  Tandy initally did
> >that to save parts. Really bad.

The 1771 may have CLAIMED to have an internal data separator; performance
did not bear that out.

> Tandys EI design got me a few trips to FtWorth to massage their heads
> with a bat for what they did.

You were much too gentle.  Next time, we'll loan you a bigger bat.

> Yes, 1meg was way above the usual 190k-380k common for for DDDS drives.
> The highest I got to with MFM was 800k (80tr 2sided).
880K   but a pain to use.


> >In particular, we gave up on Micropolis because of their stubborn
> >insistence on using a leadscrew positioner, long after almost everyone else
> >went to the faster taut-band.  I still have a 96 tpi Micropolis drive that
> The disk that Shugart used while innovative was really bad for repeatability
> of position and slooowwww.

the Micropolis lead screw was SLOW.  But noticably more reliable than
either the Shugart spiral, or the split bands.