TU79 Magnetic Tape Transport

From Computer History Wiki
Jump to: navigation, search


TU79
Manufacturer: DEC
Media: standard half-inch 9-track tape
Tape density: 1600 bpi, 6250 bpi
Tape speed: 125 inch/sec
Data rate: 781 Kbytes/sec
Rewind time: 65 secs (nominal - 2,400 feet)
80 secs (maximum)
Power consumption: 2.4kVA (max - slave)
3.1kVA (max - master)
Size: 60"H x 26.5"W x 32"D
Weight: 630 lbs (master unit)
Year Introduced: 1987

The TU79 Magnetic Tape Transport (the complete name is not definitive; it has not yet been found in any original DEC documentation, but has been extrapolated from that of the TU78) seems to be a TU78 with minor changes.

Although one rumour had it that the changes were mostly cosmetic, a DEC sales brochure maintained that "Re-designed read/write electronics dramatically reduce the .. soft error rate ... These changes also improve the drive's ability to read tapes of marginal quality ... Mechanical changes (re-designed card cage, improved door, and a new power supply) .. enhance the drive's reliability, reduce the need for Field Service adjustments".

It was an advanced large auto-loading magnetic tape drive from DEC, which used 2400' 0.5" wide magnetic tape on a standard 10-1/2" reel. It supported 9-track operation at 1600 and 6250 BPI; the drive could read data in forward as well as reverse direction. It provided pneumatic (vacuum) tape loading.

The TU79 supported two data encodings: Phase Encoding (PE) or Group Coded Recording (GCR). Bit density wass 1600 bits per inch for the PE format, and 6250 bits per inch for the GCR format.

The TU79 drive was used with a TM78 formatter, to interface to a MASSBUS. The TM78 could be mounted in a TU79, to produce a 'TU79 master'. A TU79 master can control three additional TU78 or TU79 drives, denominated as 'TU79 slaves'; up to four TU7x drives in total. It is also the base for the TA79 Magnetic Tape Drive.

Further reading

  • TA79, TU79 Magnetic Tape Subsystem Service Manual (EK-OTA79-SV)
  • TA79, TU79 Magnetic Tape Subsystem Installation Manual (EK-OTA79-IN)
  • TA79, TU79 Magnetic Tape Subsystem Owner's Manual (EK-OTA79-OM)

None online

External links