The 3.5-inch HD (High Density) microfloppy was first introduced in 1987, and first used on the IBM PS/2 range, and the Macintosh IIx. It quickly become almost universally used on PC and Macintosh hardware.
High density disks were recognisable by a second hole in the opposite corner to the write-protect notch and a HD logo. Their capacity was 1.44 MB in both PCs and Macintosh machines.
By 1988, the 3.5-inch disk (all types) were outselling the 5.25-inch minifloppy.
An even higher-capacity Extended Density (ED) microfloppy was introduced in 1991, with a capacity of 2.88 MB, but this variation was not widely used. Throughout the 1990s, various attempts were made to introduce higher capacity 3.5-inch floppy disk replacement, such as the Floptical disk, SuperDisk and HiFD.
Macintosh computers were the first to stop using floppy disks (on the iMac) in 1998, and during the 2000s, PC manufacturers began to remove drives from new PCs.