Project Kryoflux – Part 2: Why Bother with it?

The Kryoflux isn’t expensive, but then again, it’s not exactly disposably cheap. Floppy disks have long been obsoleted, so why even bother with it? Is it really worth it? As alluded to in the previous part, getting access to data on disks can be problematic – so I intend to go into a bit more detail about this, but the short answer is that the Kryoflux makes it easy!

You might have many floppy disks waiting to be recovered. If they’re modern High Density IBM disks that you wrote yourself, it’s unlikely it’d be too hard to recover the files off them as they’re pretty much supported by USB floppy drives (which are still available) or by moderately modern PCs. Even double density IBM disks written yourself isn’t likely to be a challenge as most floppy drives can still read them, although some will not write them. Drives are still relatively plentiful for 3.5″, so it’s easy.

Although it appears that you probably don’t need a Kryoflux for this case, there might be some compelling reasons. Copy protected disks, or disks with unusual formatting that cannot be read under the USB floppy drives include the DMF format (1.68Mb) that used different sector lengths – i.e. Microsoft’s way of reducing the number of floppies used to distribute software, or 1.72Mb format which used 82 tracks and were popularized by Winimage and other disk utilities like 2M which allowed you to cram more onto a floppy. Little did we forsee that these “formats” worked well with Windows 95/98 but fail under 2000 and above even when using native onboard controllers and are inaccessible when used with USB floppies. Using a Kryoflux, these formats can be analyzed and most likely recovered from!

Another issue is that of media degradation and bit rot. Over time, the magnetic media used by floppy disks can be worn by use from friction between the head and the disk, or by a loosening of the binder adhesive used to adhere the magnetic coating to the base film. This results in a loss of magnetic material that is holding your data. Worse still, over time, dust and other contaminants which are on the surface of the disk can adhere and cause read errors and head wear. This produces a characteristic click-click-click-click-click sound which increases and decreases as the read progresses along – these contaminants can rub against the head and cause drive damage but they also cause the head to “skip” along the surface – so the magnetic flux readout in that area turns into noise rather than the actual recorded flux.

Bit rot also happens to even the most well stored media – the magnetic media slowly demagnetizes itself due to stresses like thermal cycling, and alternating magnetic fields nearby or even adjacent disks and movement of those disks. Time is the enemy.

Worse still, less carefully stored disks may have particulate matter (dust, sand) which can scratch the donut (magnetic media) causing permanent loss of drive and disk. With poorly stored media that faces the sun, the heat can cause the media to be physically warped and locally shrunk and impossible to read. So even with a Kryoflux, the cards aren’t all in your hands, but the Kryoflux appears to be more tolerant of issues and its retry algorithms can be quite useful in reassembling a complete disk from disks which may not even read in the host system anymore. Even if it doesn’t get your data back, you can see why (in many cases) and whether there’s any hope. If there is, you can even try absurdly high numbers of retries or change drives and merge the results carefully. Even better is the possibility of reading the flux data and then later (when a new sector format is available) converting the previous read into a new format without re-reading.

IBM 5.25″ drives are more difficult to get, but is still not a major issue. For basic cloning of generic MFM formats like those used by certain CP/M systems, it may be able to use regular PC controllers with special software like Teledisk (abandonware) or ImageDisk, although they have trouble handling mixed sector sizes as some controllers cannot support certain data rates or sector lengths. In many cases, the Kryoflux can make sense of these sectors, but they may not be exported to the sector format due to the logistical problem of creating mixed sector size sector images. But at least using the Kryoflux, you can see these and take whatever action is appropriate.

The other challenge comes from non IBM formatted disks – disks like the Apple 800k GCR coded double density disks. There is just no way away from specialized hardware to understand these disks on an IBM/PC. Unfortunately, the specialized hardware is often the same hardware that ends up being rare, costly and itself, worthy of preservation. If anything, we’d like to avoid shoving oodles of disks into an elderly floppy drive which may be very hard to replace and hoping it reads. What if it fails? Doing it on the native systems brings about issues of not being able to copy special disks/sector formats, and also not having sophisticated error recovery options. Transmitting and storing these images can be extremely difficult as connectivity has moved along, and older systems often have storage and RAM limitations.

The Software Preservation Society is astute to these problems – and their claim that our “art and digital heritage” is being lost on magnetic media isn’t far from the truth. The ROM chips that preceded the floppy disks are inherently stable – but the magnetic media and media that have since surpassed it just aren’t as stable.

Why did I bother?

People who know me will probably object and stop me here and scream – but you’ve always been a PC person! Okay, yeah, pretty much. But the Kryoflux offers me opportunities to recover more from the Kaypro CP/M disks. But that’s a steep price to pay for a few disks.

Well, as it turns out, one of my colleagues (Robert, also the person who let me into the Syquests I recovered earlier) at UNSW who has access to the records room for the Water Research Centre and inside was a treasure trove of old Mac formatted disks. Most of them were Double Density 800k GCR coded and I knew there was no way I would be able to find an old Mac nowadays and make it work. Even finding a working monitor could be an issue with their “special” monitor connections and all.

I should make a note that everything here was done purely non-commercially. My tinkering with their floppy disks and recovery was self-initiated, and no compensation was requested nor offered. It was a labour of love. None of the recovered data was used by UNSW – and none of it had contributed to their operations in any way.

So I guess, what follows is a “small list of floppies” (20 or so, but the total number of disks was >300) which were the reasons for buying a Kryoflux.

SS701-Install1 SS701-Install2 SS701-DiskTools SS701-Fonts SS701-Tidbits SS701-MacintoshBasics

Ever seen an original Macintosh System 7.0.1 Install Disk set? Neither have I until now. But these gems heralded the new era of High Density floppy drives, prominently displaying a warning not to insert it into double density double and single sided drives. When I was in primary school, I had fond memories of the compact Macintosh LC II which ran System 7 and featured a colour GUI (512×384 from memory). This was a wonder compared to my monochrome 386SX I used at home. This set even has the tutorial disk titled Macintosh Basics.

Hypercard 22A wonderful piece of software that was “miles” ahead of its time. It offered hyperlinked slides with scriptable programmability and embed abilities and ran on System 7 (this one is Version 2.2). The things this can do were very advanced for its time, and easy to use – one can argue that Powerpoint hasn’t matched it in all regards even today.



System 7 Tune UpThis is another interesting utility disk. System 7 users would recognize this and might have used it themselves at one point in time. Interestingly, this is a Double Density disk – without the density detect hole punched, and prominently features the word Double Sided on the shutter to differentiate it from a Single Sided disk.



Apple Macplus TourAnother tasty disk – this one is a tour disk for a Macintosh Plus. Now that’s digital archaeology.





Take a Fresh Look at the Apple FamilyNow I don’t know what to expect from this one – it’s a lovely pinky watermelon colour and it seems to be a promotional disk. Maybe one of the earlier attempts at digital advertising. But whatever it is – all I know is that I want to know what’s on this!




Aldus PagemakerI also had access to some old software distributed on floppy. This one’s the first disk of the Aldus Pagemaker set – I think this would have been Version 3.0 or older.




Clarisworks Installer British 1991There’s also good old Clarisworks – many of my primary school documents were written in it. This one says Copyright 1991 – that makes it (likely) 22 years old. Considering that people consider magnetic media retention to be between 10-30 years, it’s high time this one got some attention.



Ontrack Disk ManglerHere’s a disk for the support software for the Syquest drive under Mac. Interesting, because I didn’t know Ontrack made Disk Manager for Mac. I remember their days when they made software for PCs to bypass BIOS limitations by inserting an INT13h layer on startup, but this caused many issues with different OSes and it was then known as Ontrack Disk Mangler. Funny how Ontrack are now data recovery specialists …


MS Excel4 for Mac D1There was also Microsoft Excel for Mac version 4. And also Microsoft Word for Mac, version 5.

MS Word5 for Mac D1






Imation TranslucentAlso worth taking a look at was all of the document floppies left behind by former students. Many of them were cryptically labelled, or not labelled at all … this one is a translucent Imation floppy (when floppies got cheap and nasty – notice the lack of fabric lining on the inside of the shell). This is a rare one as it’s Mac preformatted – these weren’t all that common.


Fuji DD 1SAnd here’s a special. This is a single sided double density disk. It’s considered a rare find since 3.5″ disk drives tended to be double sided except for the earliest ones. When they were labelled single sided, it implied that only one surface was verified – the drive itself doesn’t know the difference and in some cases, there was no standardization as to which side would be the single side, so often both sides were functional. As an aside – we know who owns this disk …

Toshiba MS-DOS 33


Of course, it wasn’t only Apple floppies that were interesting. There were several PC ones too – this one appears to be MS-DOS v.3.3 for a Toshiba laptop




nt4-d1 nt4-d2 nt4-d3And this is a set of disks for Microsoft Windows NT 4 Workstation. It was an OEM set, but I had never laid my hands on one of these ever!




Yeah. I know. You really have to be a geek to get excited about a few old floppies which nobody has paid attention to for many years. But there’s something special about putting your hands on something that’s old – the nostalgia one gets.

As an aside … we discovered this too – System 7 (I think) Install CD for a Quadra 610/630 still in its caddy! Another blast from the past!

Quadra 610/630 Install CD in Caddy

We didn’t find the machine though … onto the next part …

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5 Responses to Project Kryoflux – Part 2: Why Bother with it?

  1. Pingback: Project Kryoflux – Part 3: Recovery in Practise | Gough's Tech Zone

  2. Pingback: Project Kryoflux – Part 1: The Board and Associated Hardware | Gough's Tech Zone

  3. Caroline Martin (University of Manchester Library, UK) says:

    Hi, If I power off the floppy drive first, can I then disconnect the floppy drive from the Kryoflux board (even though the Kryoflux board still has power)? At the moment, each time I want to try another floppy drive, I power off the whole PC (so the Kryoflux board goes off too) before I power off the floppy drive and replace it with another one. I’m really worried about damaging the Kryoflux board.

    • lui_gough says:

      Generally, hot-swapping of drives with either the board or floppy drive powered on is a recipe for disaster. Some of the pull-up units have failed through careless or improper hot swapping. Regardless of situation, removal of all power before disconnecting or making connections is highly recommended, as is taking proper precautions against static electricity induced damage.

      That being said, if you only have two drives to swap between, consider using a single ribbon and hooking the A drive assignment to one, and the B drive assignment to the other. Then, you can switch between the two in software, without having to worry about cable wear, or possible damage to the board from ESD or accidental improper connections.

      If you have more drives, and don’t want to go to the hassle of shutting down everything – your options really depend on your power configuration. If you are using the internal power from the ATX power supply, you cannot remove power safely without shutting down the system – so that’s a no go. For 3.5″ drives, I have gotten away with a homemade USB + switch on 5v + connector end cable which thus allows me to remove power without disturbing the ground connection (which should prevent a severe switch-on transient), and for 5.25″ I use a switchable external standalone power supply.

      The procedure I follow is:
      1. Turn off power to drive while keeping the ground connection intact.
      2. Unplug the Kryoflux board from the USB cable (thus isolating power to it).
      3. Remove power connection to drive, thus isolating the whole setup and making it safe to change over.
      4. Change over the ribbon from one drive to the next.
      5. Plug in the new drive to the power supply BUT LEAVE SUPPLY OFF!
      6. Plug in the Kyroflux board to the USB bus.
      7. Power on the power supply to drive.
      8. Run a calibrate command to ensure the drive is responding correctly. If not, wiggle/re-seat edge connectors (common issue on 5.25″ drives) and check cable orientation.

      Overall, I have done this procedure over 20 times and haven’t encountered any issues, but I would suggest you keep boards “on hand” if failure is not an option. If you have more boards, you can “dedicate” boards to a given floppy drive set and avoid the cable-swapping mess, although you will need to still carefully plug-and-power each board and drive as needs dictate. I cannot be held responsible if you run into issues – sometimes an unlucky static discharge can take out a chip and kill the board, and to that end I have been rather lucky seeing as I take minimal to no ESD precautions.

      – Gough

  4. Caroline Martin (University of Manchester Library, UK) says:

    Thanks so much for your advice. That is really useful.

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