IBM introduces the Model 3340 hard disk drive system for its System/370 mainframe computers. Housed in a large casing similar to a combined washer and dryer, this is the birth of modern hard disk technology, with read and write heads integral to the drive itself rather than being mounted on an arm which reaches into the drive casing. The 3340’s removable modules, each containing drive platters and the read/write heads, can be swapped out with other modules containing other drives. IBM ships the 3340 with two maximum storage capacities: 35 megabytes or 70 megabytes; the unit is internally called a Winchester hard drive, a case of a code name that sticks well beyond development. The 3340 is available through 1984.