[vcf-midatlantic] How To Geek article on floppy data recovery
hjohnson at retrotechnology.info
Wed May 20 17:08:48 EDT 2020
Reply to David Gesswein:
Sorry for the delay in reply, I work offline from this discussion group,
and don't read it daily as most do. I always appreciate the informed
views of my good friend David. Especially so in this case because, as he
points out, he is a producer of similar tech, for MFM hard drive data
recovery *and* emulation. He knows more than I.
I acknowledge the value of lower cost. But it creates a market where
more costly solutions are discouraged. He discusses cost AND time, as
user issues. Some people give up their time, to save costs; some give up
costs to save their time. But more buy cheap, and sometimes audience
A consequence of inexpensive items is that most do not stick around
long. that's why I brought it up! But others can try to recreate them
when they aren't available (reliably). Thus the "blue pill"
Greaseweasel saga, seems to be, to either build a more reliable one (use
the proper CPU chip); or to build one on a better CPU (to move forward).
My thanks to Jeff Jonas for passing along some Facebook/greaseweasel
info, that is where they congregate.
"the projects don't cooperate" is a problem, as David describes. I
agree. Developers tend to redevelop rather than rework. Also, old stuff
gets lost, or may be hard to recover for redevelopment. This is true in
most technology; it's ironically true in vintage computing, but
thankfully not always.
"most of the value is in the decoding code". The value is split, between
the enabling hardware to do the read; and the enabling software to
decode the sampled flux-patterns. The historic example of the Catweasel
series, is that the hardware producers did not make popular decoding
software; others did. I did not determine if the FOUR or FIVE developers
of Catweasel decoders, cooperated much or not. Each grabbed some piece
of vintage computing disks by brand & model (TRS-80 for instance).
"I image with real hardware when I have it". Yes, that was the ultimate
solution for Intel M2FM disks, which at one point were imaged by
Catweasel. The images were reproduced as floppies, and read again on
Intel systems! I'll contact David privately for more information about
his imaged disks, to route his results to active INtel Multibus
Of course, we in vintage computing are generally interested in "real
hardware". But I get
pushback often, in advocating use of period PC-compatibles to image
conventional diskettes (made with Intel/NEC/WD floppy disk controller
ICs) with Dunfield IMAGEDSK tools. "I hate old PC's!" is the most terse
way to describe that. Thus the value of microcontroller based floppy
drive emulators and floppy recovery hardware. Well, each of us chooses
our areas of vintage interest.
I had private discussions of the topic, with "Gordon S." AKA gsteemso.
He was of a mind, that some kind of vintage-hardware solution for floppy
recovery had some merits. I think it will be a challenge to make such a
thing at the price of a few tens of dollars, like the other
microcontroller solutions. But a solution like the Greaseweasel is a
$200 built-for-you solution; some floppy emulators sell for that price.
So: a re-vintaged solution is conceivable, but I don't think it would be
At this point, the discussion is a matter of specifics and techie
details. A little too much so, for general email discussion lists like
this, I believe, and the thread seems to have died down. If that's
because I didn't reply and took some discussion privately, my apologies.
I hope those participating were informed as I was, and those interested
can find more information as they see fit.
Regards, Herb Johnson
Herbert R. Johnson, New Jersey in the USA
http://www.retrotechnology.com OR .net
preserve, recover, restore 1970's computing
email: hjohnson AT retrotechnology DOT com
or try later herbjohnson AT retrotechnology DOT info
More information about the vcf-midatlantic