Definition: RAMAC

(Random Access Method of Accounting and Control) The first computer with a hard disk. Introduced by IBM in 1956 and officially the IBM 305 RAMAC and 350 storage unit, all 50 of its 24" platters combined held less than five million alphanumeric characters. Nevertheless, it was the first time a computer could be used to find a single record from a file. Until then, magnetic tapes were the primary storage medium, and in order to find any specific data, every record had to be read starting at the beginning of the reel. Even more time consuming, trays of punch cards had to be fed through a mechanical sorter to find a desired account (see sorter). See magnetic tape and IBM.

Weighing more than a ton, about a thousand units were built and leased until production ceased in 1961. The RAMAC had a drum memory for program storage, and it was programmed via plugboard, switches and punch cards. See tabulator, plugboard and early computers.

The RAMAC - One MP3 File

Although this was amazing technology in 1956, RAMAC's 50 platters in total held the equivalent of "one" MP3 music file. The RAMAC sold for approximately $35,000 in the late 1950s, equivalent to roughly $300,000 in today's dollars. Much of the cost was RAMAC's "huge" disk system. (Images courtesy of IBM.)

RAMAC Resurrected

In 1994, IBM named its hard disk array RAMAC. In the 38 years since RAMAC was launched, the platter density jumped from two thousand to 260 million bits per square inch. Access time decreased from 600 to 9.5 milliseconds. (Image courtesy of IBM.)

Would They Have Believed It?

This is a hard drive sale at a Micro Center store in 2022 for 800,000 times as much storage as the RAMAC. (Image courtesy of Micro Center.)