HP 7901A Operating And Service Manual page 24

Operation
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FRONT PANEL FEATURES
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1. UNIT SELECT switch (inside front panel). Position of switch provides logical
identification of the disc drive to the controller. Up to four disc drives may be
addressed by a single controller. Unit identification (0 thru 3) indicated on
front panel.
2. DRIVE FAULT indicator lamp. Lights whenever an illegal memory operation is
attempted, a malfunction occurs in the read/write hardware circuitry, or if a
seek operation is not completed in 850 milliseconds.
3. DATA PROTECT indicator lamp. Lights whenever the DATA PROTECT switch is
in the ON position. When lit, disc is protected against any write operations.
4. DOOR UNLOCKED indicator lamp. Lights when the spindle has stopped rotating
and the carriage is retracted.
5. DRIVE READY indicator lamp. Lights when the disc drive motor has reached
2400 r/min, the cartridge has been purged of contaminated air by the filtration
system, and the heads are in a loaded position over cylinder zero. Stays lit during
legal memory operations.
6. DATA PROTECT switch (inside front panel). Turns data protection feature on or
off. When activated, protects removable cartridge disc from any write operations.
7. UNIT SELECT indicator lamp. Lamp lights behind the unit number selected by
UNIT SELECT switch.
Figure 3-1. Disc Drive Front and Rear Panel Features (Sheet 1 of 2)
7901A
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