Floppy disk data separators...

Chuck Guzis cclist at sydex.com
Sun Jun 13 16:17:27 CDT 2010

On 13 Jun 2010 at 18:17, Tony Duell wrote:

> I've heard many complaints about the TRS-80 model 1 disk controller
> which used a 1771 with the intenral data separator. But I ran a model
> 1 for quite a few yesrs with a 'stock' expanison interface (no
> doubler, no date separator mod) and never had a disk error. Yes, I
> kept the heads clean. Yes, I checked the drive speed from time to time
> (but never had to adjust it). 

Didn't at least one of the "disk doublers" for the Model 1 use a one-
shot data separator, complete with 10-turn pots for adjustment?

I suppose that the internal data separator on a standard 8" line-
powered drive wasn't too bad, as those tended to have heavy spindle 
flywheel/pulleys.  As reliable as AC line frequency--until the belt 
started to slip...

Early 5.25" drives (Micropolis, Shugart...) had much less robust DC 
motor/tach setups.

Did any consumer-level operating system ever check spindle speed as 
part of its normal operation?   It would seem to be an easy check to 
do while waiting for a drive to come ready.


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