Using The Labels Bypass Define Attribute; Using Scratch Tapes - HP BACKCOPY Reference Manual

NOTE: Though the VOLUME attribute is required for CLASS TAPEDEFINEs and optional for CLASS
TAPECATALOGDEFINEs, you cannot specify it for LABELS BYPASS DEFINEs. For more information
on CLASS TAPECATALOGDEFINEs, see the DSM/Tape Catalog User's Guide.
In your DEFINE for a labeled-tape RESTORE process, specify one of:
LABELS BACKUP
LABELS IBMBACKUP
LABELS BYPASS
For the RESTORE process, use the VOLUME attribute to specify the volume ID of a single labeled
backup tape or volume IDs of multiple labeled backup tapes.

Using Scratch Tapes

The RESTORE utility is unable to use scratch tapes because it reads existing data. You can use
either BACKUP or IBM (Backup) tapes for the RESTORE process, and you must specify the VOLUME
attribute for any labeled tape RESTORE processes.

Using the LABELS BYPASS DEFINE Attribute

Use the LABELS BYPASS DEFINE attribute only with NonStop BACKUP or IBM labeled backup
tapes. You cannot read ANSI labeled tapes using the LABELS BYPASS DEFINE attribute.
The LABELS BYPASS attribute lets you:
Restore files even after you have received a parity error using NonStop BACKUP or IBM
labeled tapes.
◦
If a parity error occurs when RESTORE is attempting to read the label of a NonStop
BACKUP or IBM labeled tape, the automatic volume recognition (AVR) process fails and
the tape is automatically unloaded.
◦
To recover from a parity error on volume one of a labeled-tape RESTORE process, use
the LABELS BYPASS attribute in a DEFINE. In a subsequent RESTORE process, the LABELS
BYPASS attribute lets RESTORE skip the read process of the BACKUP labeled tape.
RESTORE only reads the beginning-of-volume label (VOL1) and the beginning-of-file-section
label group (HDR1, HDR2) to identify the tape.
◦
Any request for a labeled-tape operation in LABELS BYPASS mode goes to the operator
console ($0) and the MEDIACOM console (if one exists) to receive operator permission.
To permit the request and release the tape drive for use in LABELS BYPASS mode, the
operator must issue the appropriate MEDIACOM ACCEPT command.
Restore multiple tape sets that consist of both labeled and unlabeled NonStop BACKUP tapes
by using the LABELS BYPASS DEFINE attribute. This type of process causes additional prompts
to be issued by RESTORE.
Mount the tape for a RESTORE process without having to specify the tape volume ID in your
DEFINE, if you restore a NonStop BACKUP labeled tape.
176 RESTORE
Identifies the format of the tapes to be read for the RESTORE process as NonStop BACKUP
labeled tapes. Labeled backup tapes written by BACKUP always have an ANSI label with a
B in the Label-Standard-Version field in VOL1, and the files are in tape format 3.
Identifies the format of the tapes to be read for the RESTORE process as IBM labeled tapes.
The IBM labeled tapes always have an IBM standard volume label in the Label-Standard Version
field in VOL1, and the files are in tape format 3.
A special purpose DEFINE attribute that lets you recover from parity errors you might have
received while attempting a RESTORE process using a NonStop labeled backup tape.