Apple Floppy Drives (was: More Apple Pimpers)

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Tue Nov 6 21:48:50 2001

RE: apple II

I've worked around and with them. Never serious 6502 programming but
used
apps on them like UCSD pascal. The disks worked ok compared to my NS*
{NS* disk controllers are reliable} and yes they were sensitive only to
the
extent that an unshielded 34pins cable didn't like to be near some
monitors.
The tubes in metal cases were ok but some of the plastic cased ones
tended
to radiate noise that the cables seemed to find.

It's beauty was the basic logic was simple as were the drive hardware and
that
helped it work better than most. Some of the better floppy systems of
the time where
neither simple nor cheap.

RE: trs80

>TRS-80 drives? I have a beautiful Model 1 setup. But talk about
trashing disks! And slow!


Slow was running the z80 at 1.7mhznot the disks fault though the step
rates were
really slow even for sa400s!..

See above and yep the tube was plastic cased and worse hot chassis!
Grounding
was poor on the drives, their internal regulators were at limits current
wise plus the
data separator in the EI was very poor. Not to worry though, as most
tended to
crash from the sloppy and noisy console to EI interface.

>What about the single board CP/M machines? I have them too. The disk
drives on the >Osborne were, based on extensive experience, the least
reliable ever made. If one
>drive could read what another had written, it was a gift from God. And
with the double density upgrade, it was much worse.


That was the drives and I always thought the SA400 series to be really
poor even
though my NS* had three of them. TM100s were not much better! Also
there was
some really bad media based on some of the media failures I've had over
the years.

The SA400 was the slowest, most unreliable floppy of the time, it made
everything
it was attached to look bad. The worst part is many vendors of early
5.25 drives
had their own version of worst at one point or another.

>And even later, how about the "ingenious" DEC double disk-munching
drives, that couldn't >format disks?


The drives could but the controller didn't, therein lies the difference.
The RX02 was
old when the 1771 FDC was young so comments based on post 1980 tech are
not reflective of then(pre 1980s). I'd call the RX01/2 the 1970s
version of an
IDE floppy as it was smart and executed commands that were higher level
than
even the 1771, mostly due to the microcoded controller. The RX01/2 were
reliable enough though the RX50 was pretty poor. In my book after the
RX02 the next useable floppy from DEC was the RX33 (teac FD-55GFR).

The commie controllers were a good idea that suffered from poor
implementation.
they were fast in themselves but the serial link was limited.

Allison
Received on Tue Nov 06 2001 - 21:48:50 GMT