fdrawcmd.sys is a floppy filter driver for Windows 2000/XP/2003/Vista/2008/7/8/10.

The driver exposes command-level access to the µPD765a floppy disk controller, making it possible to read/write many non-standard and copy-protected disk formats.

System Requirements


Version, last updated 25th April 2010 [view ChangeLog]

FdInstall.exe (111K)
Source Code (GitHub)


Advanced features unique to this driver

Other benefits


Can I use a USB floppy drive?

No. USB floppy drives contain a separate floppy controller chip, which is not directly accessible from the host PC. Without access to that it’s simply not possible to support formats beyond what the drive chooses to expose (typically DOS 720K and 1.44M formats only).

Which disk formats are supported?

Most PC-compatible soft-sectored disks should work. If there’s an existing DOS/Linux utility for them, you should have no problems. If in doubt, scan the disks with SAMdisk and see what shows up.

The level of support does still depend on the specific FDC chip in your PC. Some have problems with FM encoded disks, others with 128-byte sectors. The short-write feature of the driver relies on proper DMA behaviour too. These issues shouldn’t be a problem for the majority of users and disk formats.

I’ve connected a second drive but B: isn’t available. Why not?

Modern motherboards typically only support a single floppy drive, if they support one at all. If your BIOS doesn’t show a drive type for B: then it’s unlikely to be supported by your floppy controller chip.

This also applies to the Disk2FDI method used to read standard Amiga disks. It will only work with a second drive connected to the same cable, and your FDC must support both drives. Again, a USB floppy drive cannot be used for the second drive.

How do I use the driver to read/write disk images?

You need a disk utility to make use of the driver. See the Links section below to see if there’s a specific tool that suits your needs. For general purpose copying try SAMdisk.

How can I use this driver in my own application?

See the API page for more details.

The following applications are known to use fdrawcmd.sys:

Plus many other LibDsk-enabled applications for Windows!