Digital Audio Tape (DAT or R-DAT) is a signal recording and playback medium developed by Sony and introduced in 1987.

Although intended as a replacement for analog audio compact cassettes, the format was never widely adopted by consumers because of its expense, as well as concerns from the music industry about unauthorized high-quality copies.

Meanwhile, the phenomenon of sticky-shed syndrome has been noted by some engineers involved in re-mastering archival recordings on DAT, which presents a further threat to audio held exclusively in this medium.

Included in the signal data are subcodes to indicate the start and end of tracks or to skip a section entirely; this allows for indexing and fast seeking.

[citation needed] In 1976, another digital audio tape format was developed by Soundstream, using one inch (25.4 mm) wide reel-to-reel tape loaded on an instrumentation recorder manufactured by Honeywell acting as a transport, which in turn was connected to outboard digital audio encoding and decoding hardware of Soundstream's own design.

This system was used in June 1978 to record Aaron Copland's "Appalachian Spring" by the St. Paul Chamber Orchestra conducted by Dennis Russell Davies.

The production version of the 3M Digital Mastering System was used in 1979 to record the first all-digital rock album, Ry Cooder's "Bop Till You Drop," made at Warner Brothers Studio in California.

[citation needed] Other examples include dbx, Inc.'s Model 700 system, which, similar to later Super Audio CDs, used a high sample-rate delta-sigma modulation rather than PCM; Decca's 1970s PCM system,[3] which used a videotape recorder manufactured by IVC for a transport; and Mitsubishi's X-80 digital recorder, a 6.4 mm (1⁄4 in) open reel digital mastering format that used a very unusual sampling rate of 50.4 kHz.

[citation needed] Sony continued to produce blank DAT tapes until 2015 when it announced it would cease production by the end of the year.

Although it has been superseded by modern hard disk recording or memory card equipment, which offers much more flexibility and storage, Digital Data Storage tapes, which are broadly similar to DATs, apart from tape length and thickness on some variants, and are still manufactured today unlike DAT cassettes, are often used as substitutes in many situations.

[citation needed] The DAT recorder mechanism was considerably more complex and expensive than an analogue cassette deck mechanism due to the rotary helical scan head, therefore Philips and Panasonic Corporation developed a rival digital tape recorder system with a stationary head based on the analogue compact cassette known as S-DAT.

(Lossy compression was necessary to reduce the data rate to a level that the DCC head could record successfully at the linear tape speed of 4.75 cm/s that the compact cassette system uses.)

As DCC was launched at the same time as Sony's Minidisc format (which has random access and editing features), it was not successful with consumers either.

However, DCC proved that high quality digital recording could be achieved with a cheap simple mechanism using stationary heads.

[citation needed] In the late 1980s, the Recording Industry Association of America (RIAA) unsuccessfully lobbied against the introduction of DAT devices into the U.S.

One of these efforts, the Digital Audio Recorder Copycode Act of 1987 (introduced by Sen. Al Gore and Rep. Waxman), initiated by CBS Records president Walter Yetnikoff, involved a technology called CopyCode and required DAT machines to include a chip to detect attempts to copy material recorded with a notch filter,[6] meaning that copyrighted prerecorded music, whether analog or digital, whether on LP, cassette, or DAT, would have distorted sound resulting from the notch filter applied by the publisher at the time of mastering for mass reproduction.

[citation needed] In December 1987, The Guitar And Other Machines by the British post-punk band The Durutti Column, became the first commercial release on DAT.

[10] Several other albums from multiple record labels were also released as pre-recorded DATs in the first few years of the format's existence, in small quantities as well.