HP 7900A Disc Drive

The 7900A was a combination disc drive with a fixed hard disc and a removable hard disc platter. It had a total storage capacity of 4.9MB. The 7900A had an average access time of 35ms and a data transfer rate of 245K per second. The 7900A had an external power supply (P/N 13215A, included in the price). The 7901A (introduced in 1972) had a single, removable platter with no fixed disc, and an integrated power supply.