At one time hard drives looked similar to today’s laser copy machines. As time passed personal computers became popular and the hard drive shrunk to the size of a floppy disk drive…an 8 inch form factor floppy disk drive. It was at this time when hard disk drives (HDDs) simply followed the form factors set by floppy disk drives (FDDs) and the two sizes were virtually interchangeable.
In 1988 PrairieTek broke with tradition and invented the first modern day HDD form factor that did not follow FDDs. The new form factor was dubbed 2.5 inch and it is now the common form factor used in most notebooks today. Oddly enough, 2.5 inch FF drives are actually 2.75 inches wide and can range in height from 7 to 15mm. A typical 2.5 inch form factor notebook is 9mm tall and can come with up to 500GB of storage capacity. Read more at TweakTown.