A magnetic tape drive is a type of data storage device that stores data on a long, thin ribbon of magnetic tape. Tiny magnetic particles are layered onto the tape. A magnetic field is produced by a data signal applied to a recording head, which aligns the particles on the tape. The stored data is represented by this alignment. The tape is passed over a read head, which uses the alignment of the magnetic particles to produce an electrical signal in order to read the data.
Since magnetic tape drives function sequentially, data must be read or recorded from start to finish. As a result, they are less effective for applications requiring random access, such computer file access.