TM02 magtape controller

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The TM02 magtape formatter is a MASSBUS device controller, used with 1/2" magnetic tape drives; supported drives include the TU16 and TE16 (both at 45 inches per second). It can handle 800 bits/inch (NRZI) and 1600 bits/inch (PE - Phase Encoded).

A TM02 can control up to 8 drives, although the TM02 and drives count as only a single MASSBUS device. The TM02 controller connects to all the drives over a 'slave bus'; all the drives are identical (unlike in the TM11/TU10 system.

The TU16/TM02 with an RH11 MASSBUS interface is denominated as a TJU16; with the RH70 MASSBUS interface of the PDP-11/70, it is denominated as a TWU16.


The TM02 is implemented as a set of boards, all of which plug into a custom hex-high nine-slot backplane, usually mounted in a special box in the first tape drive rack. The modules include two hex-size boards, seven quad-size modules, and six dual-high modules.

The hex modules are:

  • M8909 - MASSBUS Interface
  • Bit Fiddler
    • M8906 for use with a PDP-11
    • M8914 for use with a PDP-10

The quad modules are:

  • 3 x M8901 - Data Sync (PE)
  • M8902 - Tape Control (PE)
  • M8903 - Tape Control Common Mode
  • M8904 - Tape Control (NRZI)
  • M8905 - Maintenance Register

The dual modules are:

  • M8907 - Control and Write Drivers
  • M8908-YA
  • M8908
  • 3 x M5903 or M5903-YA

The first three are the drive slave bus interface; the last three are the MASSBUS interface.

Drive bus

To be added.

See also

External links