|Manufacturer:||Digital Equipment Corporation|
|Media:||standard half-inch tape|
|Tape density:||1600 bpi (PE), 6250 bpi (GCR)|
|Tape speed:||75 inch/sec (high speed streaming mode) or 25 inch/sec (start/stop mode or low-speed streaming mode)|
Big 9-track tape-drives for heavy backup duties.
The TU81 servo/control module uses a Motorola 6802 processor, a variant of the 6800 with 128 bytes of internal RAM and an internal clock oscillator. There is also a 6821 Parallel Interface Adapter chip used for communication between the Servo/Control microprocessor and the Formatter Write microprocessor (on a different board).
Two 6840 Programmable Counter / Programmable Timer Module chips are used to count servo tachs.
The firmware is stored in two ROM chips.