 The IBM PC XT in 1983, included an internal standard 10MB hard disk drive, and soon thereafter internal hard disk drives proliferated on personal computers, one popular type was the ST506/ST412 hard drive and MFM interface.HDDs continued to get smaller with the introduction of the 3.5-inch form factor in the middle of the decade Rodime 1983 and the 2.5-inch form factor PrairieTek 1988.Industry participation peaked with about 75 active manufacturers in 1985 and then declined thereafter even though volume continued to climb