Brief Historical Summary, IBM 350 RAMAC Disk Drive
Announced September 4, 1956
The IBM 350 RAMAC (RAMAC stands for (Random Access Method of Accounting and Control) magnetic disk drive was the first device able to provide direct access of less than a second for reading and writing or updating individually a very large number of records. The RAMAC disk drive marked the beginning of a revolution in computing by introducing transaction processing, beginning the replacement of sequential processing required with when databases had to be stored on inherently serial access media like paper or magnetic tape and punched cards.
The 350 RAMAC rotating disk drive stored 5 million characters (using a 6 bit character code plus a parity and a space bit per character) in the form of 50,000 100-character sectors. The disks were 2 feet in diameter and the disk stack consisted of 50 magnetic disks for data storage in a stack 20 inches high. The maximum access time was 0.8 seconds to any record in the stack.
Among the radical innovations beyond magnetic memory drums made to realize the RAMAC disk drive included:
Brief History
IBM established a small "advanced technology" laboratory, their first on the West Coast, in San Jose in 1952. The size was limited to 50 people and the main purpose was to acquire engineering talent on the West Coast given the reluctance on so many there to move to the IBM Laboratories back East. Rey Johnson, an inventive genius, was put in charge and given free rein to focus on projects that sometime in the future may benefit IBM. This freedom and exploratory environment led to the concept of a mass storage device to allow the implementation of transaction processing systems.
Earlier punch card accounting relied on pre-punched cards storing frequently used data that would be manually accessed to use in batch runs of new card data. Johnson believed a card to disk device could replace thisso called “tub file”. From this concept to a transaction oriented processing system based on magnetic disk files was a journey requiring innovation and dedication. The two individual most responsible for its design and implementation were Lou Stevens for the disk file and John Haanstra for the 305 system
US Patent 3,134,997, filed December 24, 1954 and granted in 5/19/64 to Stevens, Goddard and Lynott, claiming the basic RAMAC rotating disk stack and moveable head drive design.
Lou Stevens, W. Goddard and J. Lynott were all inducted into the Inventors Hall of Fame later.
The 350 RAMAC disk drive as the key component of the IBM 305 System demonstrated the value of magnetic disk storage to accounting and control applications. Today magnetic disk storage is pervasive in all computing applications and has become the way essentially all information is stored, and shared worldwide.
Additional Information
Bashe et al., "IBM'S Early Computers", MIT Press,1986, especially Chapter 8, "Disk Storage."
Kean, David W., "IBM San Jose, A Quarter Century Of Innovation”, 1977, CHM accession number: 102687875