IBM introduced the second generation of the 3 1/2" floppy drive in its PS/2 PCs in 1987. This floppy drive can write 1.44Mb or approximately 1.4 million characters to a floppy disk. This is a high density or HD floppy drive because it stores about twice the amount of data as its double density cousin.

The thirst for larger capacity drives did not stop here. In 1996, IBM introduced an extended density 3 1/2" floppy drive in its PCs. This drive can write 2.88Mb or almost 3 million characters to a floppy disk. Although offering a larger storage capacity, the extended density disk drive and floppy disk did not catch on.

The 3 1/2" high density floppy drive can use either double density or high density floppy disks. It is backward compatible with its predecessor the 3 1/2" double density drive. The extended density floppy drive is backward compatible with both its predecessors. It can use double, high, and extended density disks.

The 3 1/2" 1.44Mb high density floppy is the most popular today.