StorageTek 6 manual Matching VOLATTR and TAPEREQ Statements

Matching VOLATTR and TAPEREQ Statements

The type of request (specific or nonspecific) determines whether the HSC uses media type and recording technique information from the VOLATTR statement or the TAPEREQ statement. (See “Precedence of VOLATTR and TAPEREQ Statements” for additional information.)

The statements are searched until matches are found for both the media type and recording technique. The first control statement that matches the selection (input) criteria is used; there is no attempt to determine the ‘‘best’’ match.

Since MEDia and RECtech parameters may or may not be specified on a single TAPEREQ or VOLATTR control statement, one of the following conditions results:

•Both media type and recording technique are provided by one control statement.

•Media type is provided by one TAPEREQ statement and recording technique is provided by another TAPEREQ statement.

•Media type is provided by one VOLATTR statement and recording technique is provided by another VOLATTR statement.

•Media type is provided by a VOLATTR statement and recording technique is provided by a TAPEREQ statement.

•Media type is provided by a TAPEREQ statement and recording technique is provided by a VOLATTR statement.

As a result of determining the precedence of media and recording technique information between the VOLATTR and TAPEREQ statements, ‘‘final’’ media type and recording technique values are produced. The final media type and recording technique are compared to the aggregate media type and recording technique of the EDL. If an inconsistency is detected, a message is issued to this effect, and the media type and recording technique of the EDL are used. If the final media and recording technique are consistent with the EDL, they are used to satisfy the request, unless doing so would cause the job to fail.

StorageTek recommends placing all control statements in a most specific to least specific order. Very general VOLATTR or TAPEREQ statements should be placed last to act as a global or site defaults.

Chapter 2. Host Software Component Functions 29

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