At the end of 2025, we published the first challenges for the RedMimicry CTF. Obtaining the floppy disks themselves was relatively easy via eBay. However, I struggled to find a suitable size template for designing the labels. If you also want to create your own floppy disks: For wrap-around labels, they need to be 7 x 7 cm.

Writing to the floppy disks proved more challenging than expected. A naive attempt using a USB floppy drive was unsuccessful. The writing process was only successful on about 20% of the disks. Was it a problem with the disks themselves? Their age? Or perhaps an inadequate drive? Probably a combination of all of these.

We discovered the GreaseWeazle project in a retro forum. It's an open-source controller for internal floppy disk drives; we used the Sony MPF920-E. GreaseWeazle instruments the drive at the hardware level, thus achieving a better success rate and allowing it to rewrite damaged sectors multiple times.

The failure rate dropped below 5% with the use of GreaseWeazle. Absolutely acceptable for a medium whose last major manufacturer ceased production 15 years ago. Writing to a disk takes approximately 2 minutes. This allowed us to write all the disks in a single workday.

In addition to the solutions submitted on our CTF platform (  rcr.sh  ), the floppy disks have been an eye-catcher and a conversation starter at every event so far!

If you don't have a floppy disk yet, feel free to drop by one of the events linked on our homepage.