Drum memory

Drum memory was a magnetic data storage device invented by Gustav Tauschek in 1932 in Austria.

In most designs, one or more rows of fixed read-write heads ran along the long axis of the drum, one for each track.

In November 1953 Hagen published a paper disclosing "air floating" of magnetic heads in an experimental sheet metal drum.

In the era when drums were used as main working memory, programmers often did optimum programming—the programmer—or the assembler, e.g., Symbolic Optimal Assembly Program (SOAP)—positioned code on the drum in such a way as to reduce the amount of time needed for the next instruction to rotate into place under the head.

This method of timing-compensation, called the "skip factor" or "interleaving", was used for many years in storage memory controllers.

The outer surface of the drum was lined with electrical contacts leading to capacitors contained within.

Magnetic drum memory units were used in the Minuteman ICBM launch control centers from the beginning in the early 1960s until the REACT upgrades in the mid-1990s.