The IBM 7330 Magnetic Tape Unit was IBM's low-cost tape mass storage system through the 1960s. Part of the

IBM 7 track IBM's first magnetic-tape data storage devices, introduced in 1952, use what is now generally known as 7-track tape. The magnetic tape is 1/2" wide, and there are six data tracks plus one parity track for a total of seven parallel tracks th ...

family of tape units, it was used mostly on

1400 Year 1400 ( MCD) was a leap year starting on Thursday (link will display the full calendar) of the Julian calendar. The year 1400 was not a leap year in the Proleptic Gregorian calendar. Events January–December * Henry IV of Englan ...

series computers and the

IBM 7040 The IBM 7040 was a historic but short-lived model of transistor computer built in the 1960s. History It was announced by IBM in December 1961, but did not ship until April 1963. A later member of the IBM 700/7000 series of scientific compute ...

/7044. The 7330 used

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnet ...

up to long wound on reels up to diameter.

Data format

The tape had seven parallel tracks, six for data and one for

parity Parity may refer to: * Parity (computing) ** Parity bit in computing, sets the parity of data for the purpose of error detection ** Parity flag in computing, indicates if the number of set bits is odd or even in the binary representation of the ...

. Tapes with character data (BCD) were recorded in even parity. Binary tapes used odd parity. (709 manual p. 20) Aluminum strips were glued several feet from the ends of the tape to serve as beginning and end of tape markers. Write protection was provided by a removable plastic ring in the back of the tape reel. A ¾ inch gap between records allowed the mechanism time to stop the tape. At 200 characters per inch, a single 2400-foot tape could store the equivalent of some 50,000

punched card A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...

s (about 4,000,000 six-bit bytes). Low speed (36 in/s) dual density (200, 556).

External links

Bitsavers.org Magnetic Tape Equipment manuals
(PDF files) 7330 7330 Tape 7330 {{compu-storage-stub