Quarter-inch tape drives: leading the pack for secondary storage

In the late seventies, two concepts were devised which together allowed the development of today´s high performance data cartridge drives. The first concept was “streaming”. If the data rate of the storage device was slightly slower than the data rate to or from the host computer, then data flow between the two devices would be continuous. The buffers within the host system would act as reservoirs to regulate the flow of data. There would be no need to stop and start the recording medium between data transactions. This allowed considerable simplification of the tape drive mechanism. The second concept was that of the data cartridge itself. Although deceptively simple in appearance, the data cartridge contains a complete mechanism to drive and guide the tape with high precision. In quarter-inch cartridge drives, data is recorded in the so called “serpentine” fashion. Recording starts on a particular track at the beginning of the tape and runs to the end of the tape. The recording head is then repositioned to a new track location and recording takes place in the reverse direction of the tape motion