Hard Drives

In September 1956, the first hard disc drive – the IBM 350- was introduced. It was part of the IBM 305 RAMAC (random access method of accounting and control) computer. With a size of 60 x 68 x 29 inch and a weight of a ton, the hard disc was able to store barely 5 MB.

The IBM consisted of fifty 24 inch (61 cm) wide, vertically stacked discs, which reached 1200 revolutions per minute. Also there were only two grapplers that placed the read/ write heads on the desired track. Therefore the access time was 600 milliseconds and the data transfer rate about 1 KB per second. On each of the 100 tracks per disc surface 100 Bit per inch could be recorded.

The IBM 305 RAMAC was rented to companies for ca. 3.200 $ per month.