Allied troops only discovered Germany's tape recorders at war's end
During the Second World War, Allied listeners monitoring Nazi radio realised Germany had some new way of recording broadcasts, but they could not work out what it was. The answer, magnetic tape, surfaced only when Allied forces captured German recording equipment as they advanced across Europe. Americans then brought it home and turned it into an industry.
Fritz Pfleumer invented magnetic tape for sound recording in Germany in 1928, building on earlier Danish work that recorded onto magnetic wire. The idea is simple: a thin magnetisable coating on a long plastic strip stores signals as it passes a recording head. Rising political tensions and war kept further German developments largely secret. Afterwards Jack Mullin, John Herbert Orr and Richard Ranger developed commercial formats in the United States, and the singer Bing Crosby, an early enthusiast, invested heavily in Ampex, a company building tape machines.
The impact on broadcasting was enormous. Radio had always gone out live; tape let programmes be recorded and aired later or repeated. From the early 1950s computers adopted tape for data storage, and videotape followed for television, home VCRs and camcorders, even storing medical data such as heart recordings. Information is laid down in tracks, either running along the tape's length or slanting across it in the helical-scan method used by most video machines.
Tape is not built to last forever. Depending on conditions, it can begin to break down after 10 to 20 years. Tapes made in the 1970s and 1980s often suffer from sticky-shed syndrome, in which the binder holding the coating absorbs moisture and decays; gently baking them at low temperature can revive them long enough to copy the contents elsewhere. Archival formats such as LTO are the exception, designed specifically for long-term storage.
Newer media replaced tape in many roles: hard drives displaced cassette loaders on home computers, CDs and MiniDiscs overtook audio cassettes, and DVDs pushed out VHS. Yet it survives for backups, and as of 2014 Sony and IBM were still pushing its capacity higher.
Source: Magnetic tape
