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by tiben_ 2630 days ago
"With rare, old media like that, the best chance to preserving them is reading the raw magnetic flux data with specialized equipment"

Kryoflux is great for that. https://www.kryoflux.com/?page=kf_features

1 comments

Or if you prefer free-as-in-speech kit, there's also Discferret (www.discferret.org) and a ton of other similar community-developed tools :)

(Full disclosure: I'm one of the guys behind Discferret but it hasn't seen much dev work recently due to lack of time on my part)

Seems the correct project URL is : https://discferret.com

That's interesting i was not aware of this project. I'll take a further look asap. Is there some feature/comparison sheet with Kryoflux available ?

Sorry, quite correct. Apparently I can't even remember my own domain name!

It'll do exactly what a Kryoflux can do, including flux-transition-level read and write. (I'm not sure if the Kryoflux can write). The big differences are that it has a complete Shugart drive interface which matches what floppy drive datasheets advise -- so it's fully open-collector, with the right type of gates.

This also makes it very flexible -- it's been used to read ST506 MFM/RLL drives and decode the resulting output. It's been connected to NEC 8-inch drives with non-Shugart interfaces.

Its only major problem was that it was expensive - about $150 per unit. You could probably get that down a lot by using a more appropriate FPGA. If I did it again, I'd probably use a Lattice MachXO and the Yosys/Nextpnr toolkit, and possibly an STM32 microcontroller.

Practically speaking if you didn't need Winchester support, you could probably use the STM32's timer and PWM peripherals with DMA reload, leaving a single-chip solution with a bit of LSTTL for the drive interface.

Heads up, store.discferret.com isn't resolving.
The store closed years ago. I was working 7am-6pm for a long while and just didn't have the time to put in.

I still have about a dozen boards and a few components, actually. Look me up on Twitter (@philpem) or Mastodon (m0ofx@mastodon.social) if you're interested in a board, my usual offer is "beer money plus shipping" :)

Thank you for theses details. Kryoflux can write back a read raw stream or some common image formats (IFP, ADF, G64 etc.)
Oh, wow. This is pretty cool. I've got some fairly oddball 5 1/4" disks from the 1980's that I'd like to try to preserve, and this looks like it would do the job. I'll echo what another comment says-- the store URL isn't resolving. I'd love to purchase one of these units.

I thought about using Kryoflux in the past, but their licensing is a complete non-starter for me. I'm not going to purchase hardware and license software that limit what I am allowed to do with it.

Unfortunately I don't sell the ready-made units any more -- they're just not cost-effective to sell like that at a price the market will bear.

I want to do a redesign with more cost-effective components (an STM32 Nucleo and a shield or Morpho backpack is one idea I'm considering).

I do have some PCBs left over, a bill of materials and can give you some guidance with part substitutions if you want to DIY one. Feel free to drop me a note on Twitter (@philpem), Mastodon (https://mastodon.social/@m0ofx) or email (via www.philpem.me.uk) if you're interested.