=== PC Floppy Drive types ===
The IBM PC supports two 3 standard diskette formats on a 5.25 inch drive:* The first is double earliest IBM PCs used single-sided, double density, 40 cylinders, 300 RPM, floppy drives which yields yield a capacity of 360KB 160KB per disketteside. This is And MS-DOS 1.0 only supports single-sided drives. * Double-sided drives were introduced in the original IBM PC in 1982 and are supported in MS-DOS 1.1. They originally had a capacity of 320KB per diskette. MS-DOS 2.0 extended the capacity to 360 KB with a new disk format. The double density drive rotates at 300 RPM[https://minuszerodegrees.net/5150/early/5150_early.htm Source]* The second format A new floppy drive was introduced with the PC/AT in 1984. It is double sided, quad density, 80 cylinders, with a total capacity of 1.2 MB. The high density drive rotates at '''360 RPM''', so only 15 sectors can be written on a track instead of 18.
The IBM PS/2 introduced two standard 3.5 inch diskette formats:
* The first is a double sided, double density, 80 cylinders, format yielding a capacity of 720KB. The double density drive rotates at 300 RPM.
* The other is double sided, quad density, 80 cylinders, with a total capacity of 1.44 MB. The high density drive rotates at 300 RPM.
Note: The earliest IBM PCs used single-sided floppy drives and MS-DOS 1.0 does not support double-sided drives. Double-sided drives were introduced in the IBM PC in 1982 and are supported in MS-DOS 1.1. [https://minuszerodegrees.net/5150/early/5150_early.htm Source]
Fun fact: The original IBM PC didn’t have a hard drive, even as an option. And MS-DOS 1.x didn't have any support for hard drives either. Hard drives only became a thing with the introduction of the IBM PC/XT and MS-DOS 2.0 in 1983. But the floppy drive was not the only option to load programs on the original IBM PC. You could also use a tape deck, just like on Amstrad CPC. However, the tape port disappeared with the PC/XT. [https://en.wikipedia.org/wiki/IBM_cassette_tape Source]