| | | | A device for the recording and playback of magnetic tapes. Drives can be of the helical or linear type, in which the tape reading /recording head touches or does not touch the tape respectively. Similar to a tape recorder, it accesses data in a sequential manner, i.e. it must read all the preceding data bolcks on the tape before getting to the data that is required. This means they are slow compared to other magnetic storage devices such as hard disk drives which allow for random access, however the speed deficit is offset by the fact that the media (tape cassettes) are cheap which makes it an ideal method for backups / archiving. In addition, whilst data access may be slow, the streaming of data to be stored to the tape can actually be very quick, with some drives managing 80MB/s or greater, that being comparable with hard disk drives. Tape autoloaders or libraries are devices incorporating a tape drive that are able to load and unload tapes automatically, making archiving and accessing large backups (or numbers or backups) easier. There are a number of interfaces used to connect the tape drive to a computer. The most common of these at present is the SCSI interface, however they may also be connected via Fibre Channel, IDE, Firewire, USB and more. The naming convention for tape drives is normally in terms of the maximum capacity of tape useable, with a 2:1 compression ratio. For example an 80/160 drive can store 80GB of data uncompressed or 160GB with a compression ratio of 2:1. | | | |
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