Any of several types of assemblies where audio tape is encased in a self contained mechanism that provides very simple insertion and/or removal from a tape recorder or playback machine. These self contained mechanisms (the cassette) usually provide all of the wheels and rollers necessary for tape to be able to be moved past a tape head. All that is required of the tape playing/recording machine is to have motors, capstan, pinch roller, gears, and mechanisms designed to provide the torque to get the tape moving through the cassette and past an opening where the machine’s tape head comes into contact with the magnetic tape for recording and playback purposes.
There have been many types of cassette tape used over the years in audio and video, including 8-track, Beta, VHS, 8mm, and DAT (a.ka. R-DAT, S-DAT, and 4mm), but one type has been so ubiquitous that it’s “real” name has become less known. It is instead simply known as the generic “cassette tape.” The given name for this format years ago was the compact audio cassette, and was sometimes known as the musicassette. This format, developed by Phillips in the early 1960’s, works similar to an open reel tape machine, only the tape is much smaller (1/8 inch wide), speeds much slower (1 & 7/8 i.p.s), and the reels are housed in a cassette, which made it extremely convenient to use compared to the other options available at the time, hence its popularity.
The compact audio cassette was largely developed with dictation machines in mind (where the “micro cassette” later became standard), but quickly became a popular distribution method for recorded music. The format has also been instrumental in the explosion of home recording equipment. In the early 1980’s Teac/Tascam developed the “Portastudio,” which was a 4-track recorder designed for home studio use. By doubling the tape speed to 3 & 3/4 i.p.s and employing dbx noise reduction some pretty decent (by the standard then) recordings could be made in a true multitrack fashion.
Cassette tapes have also been widely used over the years as data storage for computer systems. Some of these have been in the form of standard (more or less) compact audio type cassettes, while others have been more proprietary formats. Today we still use several different formats of cassette tape (DAT, AIT, DLT, etc.) as a means to archive and backup important computer data.