StorageTek 6 manual Volattr, Volume Attribute VOLATTR Control Statement, VOLATTR Usage

VOLATTR

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.

Chapter 3. HSC Control Statements and HSC Start Procedure 143

1st ed., 6/30/04 - 312579601