Diskovering Nostalgia: A 5.25-inch Floppy Tale
Leontien Talboom, Technical Analyst, Cambridge University Library
Chris Knowles, Digital Archivist, Churchill Archives Centre
Over the summer Churchill Archives Centre and Cambridge University Library (UL) teamed up to figure out a workflow for 5.25-inch floppy disks. The origin of this project was last year on World Digital Preservation Day when Chris came over to the UL to see the display of older equipment from the Cambridge University Libraries’ Digital Preservation Lab, which is based at the UL. We got chatting about digital preservation and difficult-to-read carriers, specifically 5.25-inch floppies. At the time the Transfer Service was not up and running yet and so we weren’t able to do anything immediately, but this summer we were able to bring together Churchill’s floppy disks and the UL’s equipment for this exciting joint project!
The Churchill 5.25-inch Floppy Disks
Before we started our work on the transfers, we researched guides and workflows created by other institutions, the ones from the University of Michigan and Dalhousie University being of particular interest as they had a step-by-step guide to their workflow. Furthermore, the driver and software used in these guides are the same as the one available to us on CUL’s FRED, the FC5025 floppy controller. This driver and a Kryoflux, along with a separate 5.25-inch floppy drive seems to be the most commonly used solution in our community for reading these types of carriers.
After this initial phase of research, Chris brought 30 disks that Churchill has across its holdings to the UL. Our first step was to test the FC5025 floppy drive and how it worked; this was done with a test floppy disk available in the lab. This process went smoothly and we quickly moved on to the Churchill carriers. However, our success did not last for long. The first carrier from the Churchill lot did not read as easily as the test disk…
We quickly discovered that this was due to the fact that this disk was not formatted in any of the available formats provided with the FC5025 software, which is called Disk Image and Browse. While the software was able to generate a disk image in multiple formats, in all cases it would give an error message saying that multiple sectors failed to read correctly.
After this initial hurdle we undertook more research and see if we could find anything else online about this issue. We stumbled across this blog which reviews the FC5025 driver. Not only is this a very helpful blog, the comments were especially useful. Someone in this comment section mentioned how a Hex Editor can be very helpful in determining if a disk image has been successful or not. If a repeating pattern in blocks can be found in the hex editor, it means that the disk image was not successful. If there is a list of the content at the start and no repeating pattern, it means that the disk image was successful or somewhat successful.
This led us to circulating through all the options on the Disk Image and Browse software and resulted in finding some formats that worked for the Churchill carriers. This was a tedious process, but worth it when seeing actual data showing up in the editor.
Of the 30 disks from Churchill, one read without errors, and the software could create a disk image as well as extract individual files; 25 read with a significant error message; and 4 would not read at all. The 25 that read with errors resulted in files that we could open in a text editor and read some file contents. While this resulted in quite a lot of human readable content without any further manipulation, it was obvious that we were only seeing partial files, and we had no way of knowing what proportion of the disk we were seeing.
We have also discovered why this has probably happened in our case. The carriers in question were older double density carriers and had been manufactured by UK companies such as Wang Laboratory or International Computers Limited (ICL). The formats listed in the US-made FC2025 software were not as popular in the UK at the time; notably, IBM had a far smaller market share in the UK than the US, but similarly those UK brands saw little use in the US.
This is also why our coworkers across the pond seem to have a far higher success rate and ease in copying over material from these carriers, as they will be largely formatted for IBM computers, which the Disk Image and Browse software supports.
The floppy disks at the UL
In the time between writing this blog and doing the joint project, the UL has also identified a number of 5.25-inch floppy disks in the collection. All of these floppy disks sit within one collection. Luckily these were nowhere near as difficult as the ones from the Churchill collection. All of the UL floppy disks were formatted for MS-DOS, which the FC5025 floppy disks was able to read and transfer without any issues. However, transferring and ensuring that these were transferred correctly would have not been as easy if the joint project with Churchill hadn’t been completed.
Workflow and next steps
A summary of our workflow for 5.25-inch floppy disks can be found below. This workflow is heavily influenced by some of the great guides that we found online. In the future we are hoping to do more of these projects as there are other digital carriers that are difficult to read and we may be able to come up with some solutions together.
Feel free to reach out to us about floppy disks or other exciting digital forensics projects that you are working on, as we are always happy to hear about what other institutions and places are up to!
Workflow for 5.25-inch floppy disks
Using the FC5025 in the FRED (which appears to be self-contained, and not using any features of FRED other than the inbuilt FC5025 controller, the accompanying software, and the 5.25-inch floppy drive).
Determine format & operating system — There may be some indications on the label. For example Double Density, High Density, Double sided, Single Sided, etc. The manufacturer of the disk might also be a good indication of the operating system they were used with, but there are certainly generic manufacturers which will not give any indication of what type of machine they were used on.
Open software Disk Image and Browse — This software makes it possible to create disk images and, for some formats, do logical file transfers. If the format is unclear from the disk, it is useful to cycle through all the options on the machine, starting with the MS-DOS options. Some of the formats will generate disk image files no matter what type of disk has been inserted into the drive, and can capture at least some content even if the copying process showed multiple errors at all stages, but equally many or all of these disk images may be gibberish.
If the disk imaging proceeds without errors then we believe you can be confident in the copy; if there were errors, the disk image can be examined with a hex editor, or even simple text editing software, where the presence of human-readable text would indicate that you have copied at least some data, and that the Disk Type in the software used to generate the image is not too distant a relative of the actual disk type in question. At present, we have no way of determining what proportion of a disk’s content such partial copies represent.
If disk is double sided — Make sure to check the back
If disk format is not in the FC5025 list — We have had some success in creating disk images with other formats. We are unsure why this has exactly worked, but from reading sources online it seems that many of these early devices had quite a bit of overlap in the way they were formatted and operating. However, it seems that this will only ensure that text is picked up and readable in the Hex Editor and this is not always the case.
