Attaching 5.25″ floppies via USB

Attaching 5.25″ floppies via USB

Floppy disks are a relic of the past these days. You can still see the odd 3.5″ floppy – and there are even still companies making 3.5″ USB drives you can plug into your system today. But 5.25″ floppy drives (360k and 1.2 meg variety) are much more scarce. So scarce, in fact, that you’re likely not to find any outside of an old vintage computer. Most modern PC’s since the Pentium don’t even have connectors, interfaces that support them, and I know of no vendors that make USB 5.25″ drives.

So what is one to do if they have old 5.25″ floppies they need to read? Turns out others have had the same problem – so you’re not alone.

Here’s some options:

  1. Find a service that will convert them – Usually for a fee around $5-$25 per disk.
  2. Buy an old vintage Intel pre-Core based computer from eBay that has a working 5.25″ drive.
    This means a 486 or lower computer. Almost all plug-in floppy controllers require a PC who’s motherboard has an ISA interface (not PCI). You must also be careful because older 8-bit ISA floppy controllers (from the XT/AT era) often will NOT work in faster 386/486/Pentium ISA interfaces (even though they are supposed too).
  3. Use a flux-style reader. These allow you to attach a 5.25″ drive to a controller board which then connects to your USB port. The big limitation is that you cannot interact with the disks via DOS or command line options. Instead, you need to read/write whole disk images or operate at the sector level. These readers do this by reading flux data. While this is more complicated, it is the method that archivists are using to backup disks. Reading flux data gives you the ability to read/write disks from almost any platform and in any format – even copy protected disks.
    1. GreaseWeasle V4 [NEW 2022]
      Interfaces with 8″, 5 1/4″, and 3 1/2″ drives. Amazingly, it only costs $31 CAD and seems to get as good reviews as the Kryoflux. Definitely one of the cheapest options on this list. Since it extracts the raw flux transitions from the drive, any diskette format can be captured and analyzed – PC, Amiga, Amstrad, PDP-11, many older electronic musical instruments, and industrial equipment. The Greaseweazle also supports writing to floppy disks. The design is fully open and comes with no license encumberment.
      [UPDATE 10-2022] I just bought one of these and could not be happier. It’s pretty sweet!
    2. Kryoflux
      The Holy Grail of floppy readers, but not cheap at 105€. It is able to read all formats, save as a raw stream, or export to common sector formats like the Acorn Electron, Apple, Amstrad CPC, Archimedes, Atari 8-bit, Atari ST, BBC, Commodore 64, Commodore Amiga, MSX, IBM PC, PC-8801, Sam Coupe, Spectrum, E-MU Emulator & Emulator II, DEC RX01 & RX02 and many others.
    3. Device Side Data’s FC5025
      USB 5.25″ floppy controller plugs into any computer’s USB port and enables you to attach a 5.25″ floppy drive. Even if your computer has no built-in floppy controller, the FC5025 lets you read those old disks. It also understands formats used by Apple, Atari, Commodore, TI, and others.
    4. Supercard Pro
      I don’t know very much about this one, but here’s a review and this page which contains a lot of useful information.
    5. DREM
      DREM is a MFM/RLL hard drive emulator that can read raw dumps of a hard drive. It also allows you to read floppies. More here.
  4. ISA on modern PC’s

Cables/Adapters for connecting 3.5/5.25/8″ floppy drives to your PC:

  • CablesOnline
    CablesOnline has a good selection of universal floppy cables for a very reasonable price.
  • Dbit
    The DBit FDADAP board is a small adapter which adapts 8″ floppy disk drives (Shugart SA800 style bus) to work with the PC 3.5″/5.25″ floppy disk cable pinout. It has 34- and 50-pin connectors which can be connected to the PC floppy controller and the 8″ disk drive using simple straight-through ribbon cables (not included), and a 3.5″ style power connector for the on-board microcontroller

Dead/Discontinued controllers

  • Catweasel
    Discontinued PCI board for connecting to floppies. Like other solutions, it doesn’t make drives show up as a drive letter – but rather lets you read raw formats for all sorts of platforms.

Other resources/discussions:

16 thoughts on “Attaching 5.25″ floppies via USB

  1. Nice, little write-up. Do you know why 3.5″ USB floppy drives with read/write exists but not for 5.25″? Is it solely due to lack of market demand or is are there technical reasons?

    1. At time floppy drives was widely used as configuration and program storage for various industrial devices (automated CNC mills etc.), PBX communication hardware, some military hardware etc. These devices still cost a fortune and in general works just fine. Usually older devices (made circa 1980-ties) use 5.25″ floppy drives and newer ones, made before year 2000 – 3.5″ floppy drives.

  2. SuperCard Pro happens to be the most universally used floppy archiver available. With dozens of third parties supporting through emulators and utilities (which support virtually every disk format known for 3″, 3.5″, 5.25″, and 8″ disk formats). Because of this, it is the “holy grail” of floppy readers. 🙂

  3. Today is April 26th, 2021.
    When you click on the “old vintage pre-Intel Core based computer” link in the article, the first three computers are vintage Macs, which are useless because the first one has a 800K floppy drive and the other two are for parts.

  4. Can anyone tell me why I get this message (below)when I try to order the Fc5.25 controller from devise side: Access Denied This access has been administratively prohibited by the site operator. No further information is available.

  5. looking for an adapter to use on a 5.25 external drive from an older computer. Would like to read 5.25 disks with draft material, copy to CD to use revise with WORD.

  6. Where can I buy a 5.25 adapter to connect a 5.25 external floppy drive to new computer using usb…don’t say the California bay side whatever…they are out to lunch impossible to deal with…

  7. I have an old computer running Windows 10 that has the connector that works with a 3.5″ floppy drive, but the manual doesn’t talk about 5.25″ drives. I am wondering if it would work. The motherboard is a Asus P6T with an i7 920 processor. I have lots of old 5.25″ floppy drives saved from computers that I retired.

  8. Any BIOS that lets you select the 5.25″ types (360K and 1.2M) is compatible, you just have to get a matching floppy cable, or a passive adapter from the 3.5″ drive connector.
    So most PCs made in 2000-2010 also are compatible. No need to get a 486 for this…

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