IBM 5150
From Computer History Wiki
The IBM 5150 was IBM's entry into the personal computer marketplace, the IBM PC. The original configuration was for 64kb of ram, and a tape drive, but could be expanded to include a diskette drive, and a hard disk. Back then, both types of disk drives were of the 5 1/4" full height form factor.
The IBM PC, also established the 8 bit expansion slot, or ISA bus standard. thumb|right|200px|IBM PC Motherboard
The PC was replaced by the wildly popular IBM XT.