Today we will back in time and make a look over the first commercial computer, is
The IBM 305 RAMAC, publicly announced on September 13, 1956, was the first
commercial computer that used a moving head hard disk drive. RAMAC stood for
"Random Access Method of Accounting and Control". Its design was motivated by
the need for real time accounting in business. The IBM 350 disk system stored 5 million
8-bit (7-bits plus 1 odd parity bit) characters. It had fifty 24-inch diameter disks.
Two independent access arms moved up and down to select a disk, and in and
out to select a recording track, all under servo control. Average time to locate a single
record was 600 milliseconds.
The original 305 RAMAC computer system weighed over a ton and could be housed
in a room of about 9 m (30') by 15 m (50'); the 350 disk storage unit measured around
1.5 m² (16 sq ft). The first hard disk unit was shipped September 13, 1956.
The additional components of the computer were a card punch, a central processing
unit, a power supply unit, an operator's console/card reader unit, and a printer. There
was also a manual inquiry station that allowed direct access to stored records. IBM
touted the system as being able to store the equivalent of 64,000 punched cards.
Usefull Links : Mudogeek , http://en.wikipedia.org/ ,IBM Archives on the 305
