What is the Vtape 'prefix.VVE.Ddate.Ttime.LIBn' data set for?

Products

• Vtape Virtual Tape System

Issue/Introduction

What is the Vtape VTS data set 'prefix.VVE.Ddate.Ttime.LIBn' used for?

 

Environment

Release:
Component: VTAPE

Resolution

This data set is dynamically created by Vtape when Vtape is started, and then deleted when Vtape is shutdown. It is also dynamically APF authorized. 

This data set involves the Split Maintenance-Level Protection Feature of Vtape. This feature is controlled by the TASKLIB parameter in the Startup Options Section of the Vtape PARMLIB.

When set to AUTOMATIC, Vtape dynamically allocates a LOADLIB, copies into it the load modules from the SVTS PROC STEPLIB and then dynamically APF authorizes it. This LOADLIB is then used to start the SVTSAS sub-address spaces. If one of the sub-address spaces is restarted, it is restarted from the TASKLIB LOADLIB rather than the SVTSAS PROC STEPLIB LOADLIB or a link-listed LOADLIB.

Split Maintenance-Level Protection prevents the SVTS task and the SVTSAS sub-tasks from running with code at different maintenance levels or releases.

If you want this protection, but do not want Vtape to dynamically allocate and APF authorize a LOADLIB, you can change from Automatic Mode to Library Mode. In Library Mode, you allocate a LOADLIB to match the size and DCB characteristics of the Vtape  SMPE controlled hlq.CCUULOAD data set and add it to the APF authorization list. Then you can update the TASKLIB parameter to a value of this data set name, enclosed in single quotes.

For example, if you allocate and APF authorize SYS2.VTAPE.TASKLIB, you would change the TASKLIB setting to: TASKLIB = 'SYS2.VTAPE.TASKLIB'. The next time you stop and start Vtape, the designated LOADLIB will be used instead of a dynamically allocated LOADLIB.

Note: The TASKLIB LOADLIB cannot be shared by more than one Vtape Subsystem. If you have one Vtape Subsystem running on LPAR SYSA and one on LPAR SYSB, you will need two TASKLIB LOADLIBs to run both Subsystems in Library Mode.

If you have multiple Vtape VTS Subsystems sharing the same PARMLIB, you can continue to use a common Startup Options Section when running in Library Mode. To do this you would use symbolic substitution in the TASKLIB parameter setting.

Let's say that you have two systems, SYSA and SYSB, and you allocated and APF authorized two TASKLIB LOADLIBs with data set names of SYS2.VTAPE.SYSA.TASKLIB and SYS2.VTAPE.SYSB.TASKLIB. The TASKLIB parameter value would be:

TASKLIB = 'SYS2.VTAPE.&SYSNAME..TASKLIB' (the two periods in front of TASKLIB are required)

When Vtape is started on SYSA and the PARMLIB is read, SYSA will be substituted for {&SYSNAME.} in the DSN. On SYSB, SYSB will be substituted.