StorageTek Host Software Component 6.0, System Programmer'S Manual

Page: 173 / 718

Chapter 3. HSC Control Statements and HSC Start Procedure 143
1st ed., 6/30/04 - 312579601
Volume Attribute (VOLATTR) Control Statement
The VOLATTR control statement is used to specify tape volume attributes. VOLATTR
statements are read from the definition data set specified by the VOLDEF command.
(Refer to “Volume Attribute Definition (VOLDEF) Command and Control Statement” on
page 154 for details on syntax and parameters.) The VOLATTR statement must be placed
in the definition data set; it cannot be issued as an operator command.
Notes:
1. You must enter a VOLATTR statement for each media type so that the HSC can
correctly determine scratch counts and preferencing for scratch allocation. It is
important that all VOLATTR control statements be accurate if you rely on
precise scratch counts.
2. A VOLATTR must exist for ECARTs that do not have a media label so that the HSC
can distinguish ECARTs from standard cartridges.
VOLATTR Usage
When the HSC needs to determine the attributes for a volume, it searches the VOLATTR
statements in the order that they appear in the definition data set. The first statement that
matches the requested volume is used to determine the attributes that are specified on that
VOLATTR statement. The search continues for any attributes that are not specified on the
first matching VOLATTR statement. These attributes are supplied by the next matching
VOLATTR that specifies the attribute(s).
For example, if MEDia is provided but RECtech is not, RECtech takes a default value
based upon the MEDia parameter. The same situation occurs if a RECtech value is present
but MEDia is not. Thus, StorageTek recommends that users:
• order the VOLATTR statements from most specific to most general
• specify only MEDia on all VOLATTR statements and let RECtech default, or
specify both MEDia and RECtech on all VOLATTR statements.
The HSC always selects a RECtech compatible with the volume’s media type; it is not
necessary to specify RECtech on VOLATTR statements unless a specific RECtech is
desired.
If RECtech is specified for any default VOLATTRs, however, it should be specified for all
VOLATTRs to avoid obtaining MEDia from one VOLATTR and RECtech from another.
Note: Run the Volume Report utility using the NONMEDEQ option to verify that
your VOLATTRs are in agreement with the CDS volume attribute record (VAR). The
VAR reflects volume information from the LMU and can be compared to the
VOLATTRs.
StorageTek recommends that the volume attribute statements in effect be the same on all
processors; if not, results are unpredictable.
VOLATTR