HP 3000 Manuals HP 3000 Manuals
HP7980S and HP7980SX SCSI Tape Drive Support
by Lori Orvek and Jonathan Sauer
Commercial Systems Division
The HP7980S and HP7980SX drives are similar to the HP7980 and HP7980XC
devices except for their SCSI interface. While their operation is very
similar to the HP-IB drives, there are some minor differences that should
be noted.
Automatic Volume Recognition Access Time
When a tape is mounted and online is pressed, the HP-IB drive immediately
becomes active as the system reads the tape label and repositions the
tape at BOT.
When online is pressed on the SCSI drive, the system may wait up to five
seconds before accessing the tape, reading the tape label, and
repositioning the tape at BOT. This slight delay is caused by the way the
SCSI device interrupts the host when a tape is placed online.
Offline
The following describes the differences between HP-IB and SCSI when the
drives are offline:
* HP-IB
When a tape is rewound and placed offline at the end of an
operation, the HP-IB device front panel displays BOT and the
online light is off. The tape remains threaded, but the device is
in an offline state. To put the tape back online at this point,
press online.
To eject the tape when offline, press unload.
* SCSI
The SCSI device works quite differently in this scenario. When
the tape is rewound and placed offline, the tape is actually
unthreaded. The front panel displays READY. To put the tape back
online, first press enter. The device rethreads the tape. The
panel displays BOT and the device is still offline, but the tape
is now threaded. To put the tape online at this point, press
online.
To eject the tape when offline, press unload, and the door pops
open.
Powerfail Recovery
If the device is power cycled during tape activity, the device may appear
idle for some time before the system starts to recover from the power
cycle. This is because the SCSI device does not interrupt the host
system when an event like powerfail occurs.
Hardware Configuration Option 81 Not Available
The HP7980 and HP7980XC HP-IB devices provide an option through the front
panel configuration for the door to pop open when the system has rewound
the tape and put it offline. This is configuration option 81. This
option is not available on the SCSI devices.