HP 3000 Manuals

COMMUNICATOR 3000 MPE-Express 1 (SUBSYS B.40.02 and PowerPatch Tape) Based on MP

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 will
       pop 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.

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