13 Jun
2010
13 Jun
'10
2:17 p.m.
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.
--Chuck