* 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. Double-sided drives were introduced in the IBM PC in 1982. [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. But the floppy drive was not the only option to load programs on IBM PC. You could also use a tape deck, just like on Amstrad CPC. However, the tape port disappeared with the IBM PC/XT.