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 inch (13 mm) wide, and there are six data tracks plus one parity track for a total of seven parallel tracks that span the length of the tape. Data is stored as six-bit characters, with each bit of the character and the additional parity bit stored in a different track.
An IBM 704mainframe with IBM 727 7-track tape drives on the leftReel of 1/2" tape showing beginning-of-tape reflective markerA write-protection ring had to be inserted in the back of a reel to allow its tape to be written on.A reel of half-inch magnetic tape being loaded onto an IBM 729 tape drive that is attached to an IBM 1401 being restored at the Computer History Museum.
These tape drives were mechanically sophisticated floor-standing drives that used vacuum columns to buffer long U-shaped loops of tape. Between active control of powerful reel motors and vacuum control of these U-shaped tape loops, extremely rapid start and stop of the tape at the tape-to-head interface could be achieved. When active, the two tape reels thus fed tape into or pulled tape out of the vacuum columns, intermittently spinning in rapid, unsynchronized bursts resulting in visually striking action. Stock shots of such vacuum-column tape drives in motion were widely used to represent "the computer" in films and television.
The IBM 726 dual magnetic tape reader/recorder for the IBM 701 was announced on May 21, 1952.
IBM 727edit
The IBM 727 Magnetic Tape Unit was announced for the IBM 701 and IBM 702 on September 25, 1953. It became IBM's standard tape drive for their vacuum tube era computer systems. It was withdrawn on May 12, 1971.
IBM 728edit
The IBM 728 magnetic tape drive was used on the SAGE AN/FSQ-7 computer. It was physically similar to the IBM 727, but with significantly different specifications.
The IBM 729 Magnetic Tape Unit was IBM's iconic tape mass storage system from the late 1950s through the mid-1960s. It was used on late 700, most 7000 and many 1400 series computers. A new dual gap head assembly allowed read-after-write verification.
IBM 7330edit
The IBM 7330 Magnetic Tape Unit was a low cost slower tape system. It was common on 1400 series computers.
IBM 2400 Seriesedit
The 2400 Series Magnetic Tape Units were introduced with the System/360. Most were IBM 9 Track format drives, but they could be ordered with seven-track read/write heads, allowing them to read and write seven-track tapes.
Legacyedit
As of 2020, IBM still sells magnetic tape cartridge drives using half-inch wide tape in the Linear Tape-Open and 3592 formats.
Sourcesedit
IBM 726 Magnetic tape reader/recorder
IBM 727 Magnetic tape unit
Bitsavers.org Magnetic Tape Equipment manuals (PDF files)
A22-6589-1_magTapeReference_Jun62.pdf – Reference manual for 7 track drives
(photo) Sold with 705 in 1955.
Wikimedia Commons has media related to Half inch magnetic tapes.
November 23, 2023
track, first, magnetic, tape, data, storage, devices, introduced, 1952, what, generally, known, track, tape, magnetic, tape, inch, wide, there, data, tracks, plus, parity, track, total, seven, parallel, tracks, that, span, length, tape, data, stored, character. 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 inch 13 mm wide and there are six data tracks plus one parity track for a total of seven parallel tracks that span the length of the tape Data is stored as six bit characters with each bit of the character and the additional parity bit stored in a different track An IBM 704 mainframe with IBM 727 7 track tape drives on the leftReel of 1 2 tape showing beginning of tape reflective markerA write protection ring had to be inserted in the back of a reel to allow its tape to be written on A reel of half inch magnetic tape being loaded onto an IBM 729 tape drive that is attached to an IBM 1401 being restored at the Computer History Museum These tape drives were mechanically sophisticated floor standing drives that used vacuum columns to buffer long U shaped loops of tape Between active control of powerful reel motors and vacuum control of these U shaped tape loops extremely rapid start and stop of the tape at the tape to head interface could be achieved When active the two tape reels thus fed tape into or pulled tape out of the vacuum columns intermittently spinning in rapid unsynchronized bursts resulting in visually striking action Stock shots of such vacuum column tape drives in motion were widely used to represent the computer in films and television Contents 1 Technical details 2 Generations 2 1 IBM 726 2 2 IBM 727 2 3 IBM 728 2 4 IBM 729 2 5 IBM 7330 2 6 IBM 2400 Series 2 7 Legacy 3 SourcesTechnical details editDensity Initial recording density was 100 characters per inch Later models supported 200 556 and 800 characters per inch Inter record gap A gap initially one inch later 3 4 inch between records allowed the mechanism time to start and stop the tape Latency There was only a 1 5 ms delay for the stopped tape to reach its full reading or writing speed Markers Aluminum strips were glued several feet from the ends of the tape to serve as logical beginning and end of tape markers Write protection A removable plastic ring in the back of the tape reel was inserted to indicate that writing should be permitted Generations editIBM model726 727 728 729 7330Density chars in 100 200 248 200 556 800 200 556Tape speed in s 75 75 75 75 112 5 36Transfer rate chars s 7 500 15 000 18 750 15 000 41 700 60 000 22 500 62 500 90 000 7 200 20 016End of record gap 1 inch 100 chars 16 67 words 0 75 inches 150 chars 25 words 0 75 inches 186 chars 31 words 0 75 inches 150 417 600 chars 25 69 5 100 words 0 75 inches 150 417 charsRewind speed in s avg 75 read backwards 500 500Start time ms 10 5 5Stop time ms 10 5 5Max length of reel ft 1 400 2 400 2 400 2 400 2 400Base composition cellulose acetate PET film or cellulose acetate PET film or cellulose acetate PET film PET filmIBM 726 edit The IBM 726 dual magnetic tape reader recorder for the IBM 701 was announced on May 21 1952 IBM 727 edit The IBM 727 Magnetic Tape Unit was announced for the IBM 701 and IBM 702 on September 25 1953 It became IBM s standard tape drive for their vacuum tube era computer systems It was withdrawn on May 12 1971 IBM 728 edit The IBM 728 magnetic tape drive was used on the SAGE AN FSQ 7 computer It was physically similar to the IBM 727 but with significantly different specifications tracks 6 data 1 synchronization words 6 chars 32 data bits 1 parity bit 3 end of file bits words inch 41 33 IBM 729 edit The IBM 729 Magnetic Tape Unit was IBM s iconic tape mass storage system from the late 1950s through the mid 1960s It was used on late 700 most 7000 and many 1400 series computers A new dual gap head assembly allowed read after write verification IBM 7330 edit The IBM 7330 Magnetic Tape Unit was a low cost slower tape system It was common on 1400 series computers IBM 2400 Series edit The 2400 Series Magnetic Tape Units were introduced with the System 360 Most were IBM 9 Track format drives but they could be ordered with seven track read write heads allowing them to read and write seven track tapes Legacy edit As of 2020 IBM still sells magnetic tape cartridge drives using half inch wide tape in the Linear Tape Open and 3592 formats Sources editIBM 726 Magnetic tape reader recorder IBM 727 Magnetic tape unit Bitsavers org Magnetic Tape Equipment manuals PDF files A22 6589 1 magTapeReference Jun62 pdf Reference manual for 7 track drives IBM 727 Magnetic tape unit photo Sold with 705 in 1955 nbsp Wikimedia Commons has media related to Half inch magnetic tapes Retrieved from https en wikipedia org w index php title IBM 7 track amp oldid 1167712286, wikipedia, wiki, book, books, library,
