TU81 Streaming Tape Unit
| TU81 Streaming Tape Unit | |
 A TU81 | |
| Manufacturer: | Digital Equipment Corporation |
|---|---|
| Drive Controller(s): | KLESI Low-End Storage Interconnect KLESI-UA (M8739, UNIBUS); KLESI-QA (M7740, QBUS) KLESI-B (T1014, VAXBI) |
| Interface Type: | Low End System Interconnect |
| Media: | standard half-inch tape |
| Tape density: | 1600 bpi (PE), 6250 bpi (GCR) |
| Capacity: | 40 MB (1600 bpi, 2K byte blocks) 145 MB (6250 bpi, 8K byte blocks) |
| Tape speed: | 75 inch/sec (high speed streaming mode) or 25 inch/sec (start/stop mode or low-speed streaming mode) |
| Data rate: | 40 Kbyte/sec (low speed), 1200 Kbyte/sec (high; 1600 bpi) 156 Kbyte/sec (low speed), 469 Kbyte/sec (high; 6250 bpi) |
| Rewind speed: | 192 ips (average) |
| Rewind time: | 150 secs (nominal, 2,400') |
| Power consumption: | 300 VA (standby or loaded) 550 VA (maximum) |
| Size: | 41.5"H x 21.5"W x 30"D |
| Weight: | 295 lbs |
| Year Introduced: | 1984 |
The TU81 Streaming Tape Unit was a mid-range dual-density, 9-track, streaming, ANSI-standard magnetic tape drive for heavy backup duties.
The recording density, of either 1600 bpi (using PE encoding) or 6250 bpi (using GCR encoding), was selectable by software.
The TU81 servo/control module used a Motorola 6802 processor, a variant of the 6800 with 128 bytes of internal RAM and an internal clock oscillator. There was 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 were used to count servo tachs. The firmware was stored in two ROM chips.
Further reading
- TU81/TA81 and TU81 PLUS Subsystem User's Guide (EK-TUA81-UG)
No longer available online
External links
- TU81 - documentation at Bitsavers
- TU81 Magnetic Tape Subsystem Pocket Service Guide (EK-0TU81-PS-002)
- TA78 and TA81 Magnetic Tape Subsystems - brochure, covers the TU81 too
- TA79 and TA81 Magnetic Tape Subsystems - brochure, similar
