Distribution Media Format

Distribution Media Format (DMF) is a format for floppy disks that Microsoft used to distribute software. It allowed the disk to contain 1680 KiB of data on a 31⁄2-inch disk, instead of the standard 1440 KiB. As a side effect, utilities had to specifically support the format in order to read and write the disks, which made copying of products distributed on this data storage medium more difficult.