IBM MT72 magnetic tape typewriter, 1967.

Detail of tape control unit. Automatic typewriters that did away with much of the repetition involved in manual typing were available in the 1920s, using punched paper as a recording medium. The more versatile MT72, introduced in 1964 and manufactured in the Netherlands, used magnetic tape cartridges instead. A small computer linked to an IBM 72 'golf ball' typewriter allowed documents to be recorded, re-typed and corrected. Names and addreses on one tape could be added to a standard letter on another.