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The IBM 727 Magnetic Tape Unit was announced on September 25, 1953. It provided
intermediate speed, large capacity storage for programs and data, and it was also used as
a high-speed input unit for information previously recorded on magnetic tape.
Selector circuits in the IBM 701 could control from one to five 727 units. When more than
five 727 units were to be operated with the 701 system, additional circuits had to be
ordered, which could then be field installed.
Recording density was 200 bits per linear inch. Tape could be read in a forward direction
or back-spaced at a rate of 75 inches per second. Tape could be rewound at an average rate
of 500 inches per second. The reading or writing rate was 15,000 characters a second.
For transferring data from punched cards to magnetic tape, an IBM 714 Card Reader and an
IBM 759 Card Reader Control Unit were connected to the 727. The speed of recording was 250
cards a minute.
For transferring data from tape to cards, an IBM 722 Card Reader and an IBM 758 Card Punch
Control Unit were connected to the IBM 727. Records of 80 characters or less could be
punched at a speed of 100 cards per minute.
For transferring data from tape to print, an IBM 717 Printer and IBM 757 Printer Control
Unit were connected to the 727. Information could be printed at a speed of 150 lines a
minute.
The IBM 727 was also used as a tape unit with the IBM 705 Data Processing System, which
was introduced on October 1, 1954. Renting for $550 a month, the 727 was withdrawn from
marketing on May 12, 1971.
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