IBM 726 Magnetic Tape Reader/Recorder

The IBM 726 dual magnetic tape reader/recorder for the IBM 701 was announced on May 21, 1952. Unlike later IBM 7 track drives, the 726 could read backwards as well as forwards.The tape had seven parallel tracks, six for data (called a copy group, not a character) and one to maintain parity. Tapes were recorded in odd parity, to ensure at least one bit transition per copy group as well as for error checking.