For more information, see the IBM Virtualization Engine TS7700 Series Bulk Volume Information Retrieval Function User’s Guide , WP101094. 

Clarification:  Records that are listed in 11.4, “Bul k Volume Information Retrieval” on page 646 show an initial record of “ 1234567890123 ...”. This record does not exist; it is provided to improve readability. 

## 11.4.1 BVIR overview 

The TS7700 converts the format and storage conventions of a tape volume into a standard file that is managed by a file system within the subsystem. It uses an IBM-standard labeled tape volume to start a request for information and return the results. By using a standard tape volume, no special interfaces or access methods are needed for an application to use this facility. In practice, no specific applications are required because standard IBM utilities, such as IEBGENER, provide the function that is needed to request and obtain the information. 

The following steps show how information is obtained by using this function: 

1. A single data set with the information request is written to a logical volume. The logical volume can be any logical volume in the subsystem from which the information is to be obtained. 

A scratch or specific volume request can be used. The data set contains a minimum of two records and a maximum of three records that specify the type of data that is being requested. The records are in human-readable form and contain lines of character data. 

The data set can be cataloged or uncataloged (although cataloging the data set can make it easier for subsequent access to the data). On closing the volume, the TS7700 server recognizes it as a request volume and “primes” the subsystem for the next step. 

Remember:  Some information that is obtained through this function is specific to the cluster on which the logical volume is written; for example, cache contents or a logical-physical volume map. In a TS7700 grid configuration with multiple clusters, use an MC for the volume to obtain statistics for a specific cluster. Historical statistics for a multi-cluster grid can be obtained from any of the clusters. 

2. The request volume is again mounted, this time as a specific mount. Seeing that the volume was primed for a data request, the TS7700 appends the requested information to the data set. The process of obtaining the information and creating the records to append can take up to several minutes, depending on the request and, from a host’s perspective, is part of the mount processing time. 

After the TS7700 completes appending to the data set, the host is notified that the mount is complete. The requested data can then be accessed like any other tape data set. 

In a job entry subsystem 2 (JES2) environment, the job control language (JCL) to complete the two steps can be combined into a single job. However, in a JES3 environment, they must be run in separate jobs because the volume is not unmounted and remounted between job steps in a JES3 environment. 

After the response data set is written to the request logical volume, that logical volume functions identically to any other logical volume in the subsystem. Subsequent mount requests and read accesses to the logical volume do not affect its contents. Write accesses to the logical volume overwrite its contents. The logical volume can be returned to SCRATCH status and reused by any application. 

