Can something be obsolete if it never caught on? The world tends to have completely forgotten about DAT, which was supposed to take the place of cassettes but provide a pure digital experience. DAT stands for Digital Audio Tape and at one time it was going to the be the future.
The DAT tape format was a little smaller than cassette but physically had more in common with a VHS tape, including a little door on the front that protected the tape surface. The tape was 4mm wide, not too much wider than a cassette tape either.
DAT never really made much of a splash because there wasn’t a lot of content available for it. Back during its short heyday in the late 1980s, there were only a few hundred albums available on DAT, while the competing compact disk already had hundreds of thousands. DAT’s real strength was that it was recordable and portable, but that didn’t resonate with a public which was already perfectly comfortable with regular cassettes. DAT gave you real digital quality, but that didn’t sway people.
For most folks, DAT’s useful life was a mere blip in the history of technology, but if you were an IT professional in the late 20th and early 21st century, you realize that DAT had another life. Renamed DDS (digital data storage) DAT became a cheap and popular method for data backup in the days when a gigabyte was still a lot. It kept evolving to the point where one tape could store as much as 40GB (which again, seemed like a lot.) DAT suffered from the same problems as any tape, namely being fairly fragile and sensitive to heat and humidity, but it did offer a real backup solution in the days before recordable DVDs and cloud storage.
DAT finally gave way to other forms of tape storage and then to cloud or hard-drive based storage, but believe it or not it managed to have an almost fifteen-year lifespan. Not bad for a failed audio format.