Drum Memory Wave was a magnetic data storage system invented by Gustav Tauschek in 1932 in Austria. Drums have been extensively used within the 1950s and into the 1960s as laptop memory. Many early computers, referred to as drum computer systems or drum machines, used drum memory as the main working memory of the pc. Some drums had been also used as secondary storage as for instance varied IBM drum storage drives and the UNIVAC FASTRAND sequence of drums. Drums had been displaced as primary computer memory by magnetic core memory, which supplied a better steadiness of measurement, speed, value, reliability and potential for additional improvements. Drums have been then replaced by onerous disk drives for secondary storage, which had been both inexpensive and provided denser storage. A drum memory or drum storage unit contained a large metal cylinder, coated on the outside floor with a ferromagnetic recording materials. It could possibly be thought of the precursor to the exhausting disk drive (HDD), however in the type of a drum (cylinder) slightly than a flat disk.

In most designs, one or more rows of mounted learn-write heads ran along the long axis of the drum, one for each monitor. The drum's controller merely chosen the correct head and waited for the info to look beneath it because the drum turned (rotational latency). Not all drum items had been designed with each observe having its personal head. Some, such as the English Electric DEUCE drum and the UNIVAC FASTRAND had multiple heads moving a brief distance on the drum in contrast to trendy HDDs, which have one head per platter surface. In November 1953 Glenn E. Hagen of Logistics Research, Inc. printed a paper disclosing "air floating" of magnetic heads in an experimental sheet metallic drum. Flying heads turned normal in drums and onerous disk drives. Magnetic drum units used as major memory have been addressed by phrase. Drum items used as secondary storage were addressed by block. Several modes of block addressing have been doable, relying on the system.