IBM 350 Disk Storage Unit

The IBM 350 Disk Storage was a major component of the IBM 305 RAMAC (Random Access Memory Accounting) system, introduced in September 1956. The 350 Disk Storage Unit consisted of the magnetic disk memory unit with its access mechanism, the electronic and pneumatic controls for the access mechanism, and a small air compressor. Assembled with covers, the 350 was 60 inches long, 68 inches high and 29 inches deep. It was configured with 50 magnetic disks containing 50,000 sectors, each of which held 100 alphanumeric characters, for a capacity of 5 million characters.