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Hooking up an 8" floppy to a modern PC

Malvineous

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Not that I mean to keep going on about the Kryoflux, but you're right when you say the hardware is pretty simple. The KF is just a standard ARM development board with a few customisations like a floppy drive connector. The manual comes with a schematic. The firmware handles basic drive control, but the software is what makes the difference. It's this which is able to decode all the disk formats, and I believe it's so far able to do this better than anything that came before it (I think the Catweasel's poor performance is what inspired the Kryoflux in the first place.) As to whether it can write back all sorts of odd floppy formats, you'd have to ask the Kryoflux team. I believe they're able to write "weak" bits used by some copy protection schemes, so I would be surprised if there was something it couldn't write (providing of course the drive itself is able to.) IIRC analogue calibration disks are one of the things it can't write.

I am interested in reversing the process as lynchaj mentions, so you could plug the KF into a floppy controller instead of a floppy drive, and then make disk images appear as actual disks on a real machine. I believe the latest hardware revisions might be able to do this, if someone were to write the firmware for it. The Kryoflux team aren't interested in this (or writing firmware to make the KF appear as a standard USB floppy drive) because their focus is on preserving original disks, and primarily those from games. They don't see the point in wearing out floppy drives and disks by using them more than the minimum necessary to get a good copy.

I hadn't heard about the XT-FDC project, but it's great to hear people are working on things like this. The XT-FDC project though is aimed at a completely different audience than the Kryoflux is. The Kryoflux is designed to preserve the data in full - from copy protection to tracking information added by disk duplication companies. Once this data is preserved, essentially the disks are no longer important. Their biggest customers appear to be museums and the like. But the XT-FDC project seems more aimed at people who want to actually use real floppy drives, all the time. Not that that's a problem, but the two devices serve difference purposes. If you want to use floppies all the time you'll be disappointed with a Kryoflux, and if you want a flux perfect copy you'll be disappointed with anything else!
 

Chuck(G)

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I've already posted on a floppy simulator using an AVR a year ago. I've got one now using a PIC32 and am working on getting it to the point of emulating MFM hard drives. Besides, there are commercial floppy simulators already on the market. Again, nothing special.

You say "flux perfect copy". Does the KF quantitatively measure the flux; i.e. give me the flux strength in oersteds for each domain? What do you use--a special drive with a SQUID or GMR head?

You know, I've got a pile of disks with deteriorated binder--you can't put them in a drive because you'll be left with a clear cookie and a cloud of brown dust. How will the KF do with those?

I've got disks with tracks that are dynamically positioned--that is, they're all written relative to track 0--and track 0 is almost never in the same position from disk to disk. How does the KF do with those? Not to mention the floppies that I have that employ embedded servo.

Have you looked at the Disk Ferret? My feeling from what Phil has written is that it's far superior to the KF. How about the Deviceside USB unit?

There was nothing wrong with the Catweasel; only the software was lacking. I think that's because Jens was interested in the Amiga only and left the rest as an exercise for the user.

My point being is that as much as you defend the KF, you haven't even seen what lies below the surface of the issue. It appears that you're interesting in preserving computer games, not geological survey information, architectural blueprints, telemetry data or historical works.
 
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Malvineous

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I'm actually only interested in preserving my own things, and they're all PC disks anyway. I only got the Kryoflux because at the time it was the only way I could find that would allow a 5.25" floppy to be connected via USB. But you're right - once you go beyond 'consumer' games and the like, there are many specialist fields that require unique equipment. The Kryoflux is only designed to read floppy disks that you can use in a handful of consumer devices (so PC, Amiga, C64, etc.) Those disks of yours which are dynamically positioned would (I presume) not belong to one of these consumer grade systems anyway, so if that's the case it's not really what the Kryoflux is designed for. Their focus is on preserving games, and so far, they seem to support all the systems needed for all the games they are interested in. Can't really fault them for that. The fact that 8" drives work at all is just a bonus.

I would be interested to know how you intend to read those disks with deteriorated binder...

EDIT: Looking at the Disc Ferret (seems the Disk Ferret is something different entirely) it again seems to be aimed at a similar but different purpose. Like the KF they complain about the Catweasel's lack of support, but I can't see any direct comparison with the KF. It looks like the timing is faster to allow connection of hard drives as well as floppies, but since it uses the same floppy connector as the KF it is unlikely to be much different when using it with floppies (as far as what it reads off the drive.) But it does have open source firmware and software, which is one up from the Kryoflux.

I think it would be relatively simple to write firmware for both devices so you could use the KF software with the DF and vice versa, since the hardware is so similar (when using it with floppy drives at least.) But the real test is going to be what the DF software is like. The KF team are quite proud of the quality of their software (e.g. being able to correctly extract data from multiple reads of some bad sectors) so it will be interesting to see whether writing good software is as hard as the KF team have suggested!
 
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patscc

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I wonder if you can use a similar process as for 'fixing' the deteriorated binder on magnetic audio/video tape, maybe tweaking the read amplifier circuit on the drive a bit ?
patscc
 

Chuck(G)

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Pat, go find a pile of old Wabash-branded floppies and let me know how you make out. Most drives simply peel the oxide right off the first track they're on--and after that, the heads are fouled completely. I'm going to try the Nu-Finish approach to see if that makes a difference on a few of these, but I'm not optimistic. Evidently Wabash knew they had bad binder for years and so just lowered their prices rather than fix the problem. My heart sinks when I see one of those disks.

I'm playing with a non-contact method of recovery, but it means that the disk is pretty much ruined in the process, so I only get one shot at it.

(I should mention that I do data recovery professionally)
 

patscc

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Sure thing. I'll put that right in my queue of things to do.
Just out of curiosity, since I'm sure you have more of them than me, have you ever tried baking them, I think around 100 F[sup]o[/sup] is what the tape restoration guys use ?
patscc
 

Chuck(G)

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Baking will only help if your medium has picked up excess moisture--it helps a bit, but oxide shedding is still a huge problem for the vintage tape guys. They came up with the Nu-Finish solution and it seems to work some of the time.
 
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