TA11 Magnetic Tape Cassette controller

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The TA11 Magnetic Tape Cassette controller is the UNIBUS controller for the TA11 Magnetic Tape Cassette System, which includes a controller and a TU60 Dual DECasette Transport, which uses Phillips-type tape cassettes holding a specially formulated tape.

The TA11 itself is a quad board, the M7892, which plugs into an SPC slot; a pair of BC08-S flat cables which connect the board and drive. All data transfer is via programmed I/O, one byte at a time.

Device registers

The TA11 has but two registers, a 'Control and Status' register and a 'Data Buffer' register.

Register Abbreviation Address
Control and Status Register TACS 777500
Data Buffer Register TADB 777502

777500: Control and Status Register (TACS)

Error Block Check Clear Leader Write Lock File Gap Timing Error Off Line Unit Select Transfer Request Interrupt Enable Ready Last Byte Function Go
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

The functions are:

Code Function Abbreviation
0 Write File Gap WFG
1 Write WRITE
2 Read READ
3 Space Reverse File SRF
4 Space Reverse Block SRB
5 Space Forward File SFF
6 Space Forward Block SFB
7 Rewind REWIND

777502: Data Buffer Register (TADB)

Unused Data
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00