Although 5.25 floppy disks are still available for purchase, there are different specifications, and not all of them work with the Disk II drive. For example, the more “modern” high-density (HD) disks will not work. The correct specification is:

  • Double Density (DD)
  • Single Side (SS) or Double Side (DS)
  • 48 tpi

Whether you choose Single or Double Side, it doesn’t matter. But DS means that both sides of the disk can be used, and that’s why I always buy and use Double Side. But there’s a catch.