Recording tape

Magnetic tape is a medium for magnetic recording, made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders. A device that stores computer data on magnetic tape is a tape drive (tape unit, streamer).

Magnetic tape revolutionized broadcast and recording. When all radio was live, it allowed programming to be recorded. At a time when gramophone records were recorded in one take, it allowed recordings to be made in multiple parts, which were then mixed and edited with tolerable loss in quality. It was a key technology in early computer development, allowing unparalleled amounts of data to be mechanically created, stored for long periods, and to be rapidly accessed.

Nowadays, other technologies can perform the functions of magnetic tape. In many cases, these technologies are replacing tape. Despite this, innovation in the technology continues, and Sony and IBM continue to produce new magnetic tape drives.

Over years, magnetic tape made in the 1970s and 1980s can suffer from a type of deterioration called sticky-shed syndrome. Caused by hydrolysis of the binder of the tape, it can render the tape unusable.

The oxide side of a tape is the surface that can be magnetically manipulated by a tape head. This is the side that stores the information, the opposite side is simply a substrate to hold the tape together. The name originates from the fact that the magnetic side of most tapes is made of an oxide of iron. Sometimes chromium is also used.

Magnetic tape was invented for recording sound by Fritz Pfleumer in 1928 in Germany, based on the invention of magnetic wire recording by Oberlin Smith in 1888 and Valdemar Poulsen in 1898. Pfleumer's invention used a ferric oxide (Fe
2O
3) powder coating on a long strip of paper. This invention was further developed by the German electronics company AEG, which manufactured the recording machines and BASF, which manufactured the tape. In 1933, working for AEG, Eduard Schuller developed the ring-shaped tape head. Previous head designs were needle-shaped and tended to shred the tape. An important discovery made in this period was the technique of AC biasing, which improved the fidelity of the recorded audio signal by increasing the effective linearity of the recording medium.

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