The CICS® VT GLUE is called VIDCGLUE, and is automatically invoked every time a migrated data set is processed. Calls initiated from CICS terminals such as CEMT or CECI are processed by VIDCGLUE.
Calls from application programs that use the systems programming interface SET FILE or SET DATA SET are also processed by VIDCGLUE. This means that CICS file control calls have the same effect in CICS VT as they do in CICS. For example, here is the response to a CEMT transaction inquiring on the status of the file KSDS05:
I FILE(KSDS05) STATUS: RESULTS - OVERTYPE TO MODIFY Fil(VIDKSDS ) Vsa Ope Ena Rea Upd Add Bro Del Sha Dsn(VID.KSDS05 )
The CICS VT VTMD supplied transaction, described in VTMD - displaying the CICS VT DST, displays the status of migrated files in CICS. The response to the VTMD transaction is shown in Figure 2:
08/31/11 ==> CICS VT File Definitions <== 16:24:22 Filename DIM name Org Status MStatus Operations Compare KSDS01 KSDS01 ENA INI ACT R U A B D REP N KSDS02 KSDS02 ENA INI ACT R U A B D REP N KSDS02P KSDS02AI ENA INI ACT R U A B D REP N KSDS03 KSDS03 ENA INI ACT R U A B D REP N KSDS03P1 KSDS03P1 ENA INI ACT R U A B D REP N KSDS04 KSDS04 ENA INI ACT R U A B D REP N KSDS05 KSDS05 ENA INI ACT R U A B D REP N KSDS05P1 KSDS05P1 ENA INI ACT R U A B D REP N KSDS05P2 KSDS05P2 ENA INI ACT R U A B D REP N KSDS05P3 KSDS05P3 ENA INI ACT R U A B D REP N KSDS05P4 KSDS05P4 ENA INI ACT R U A B D REP N KSDS06 KSDS06 ENA INI ACT R U A B D REP N KSDS06P1 KSDS06P1 ENA INI ACT R U A B D REP N KSDS07 KSDS07 ENA INI ACT R U A B D REP N KSDS07P1 KSDS07P1 ENA INI ACT R U A B D REP N KSDS08 KSDS08 ENA INI ACT R U A B D REP N KSDS09 KSDS09 ENA INI ACT R U A B D REP N KSDS10 KSDS10 ENA INI ACT R U A B D REP N More PF3=end PF7=back PF8=fwd SYSID=S650 APPLID=CICSTS32
The status of the file according to the CEMT transaction is always consistent with the file status according to CICS VT, because CICS VT intercepts CEMT and CECI transactions and updates the CICS VT file status when necessary. This means that you have the same control over migrated files as you do with non-migrated files. For example, assume that you issue the CICS command to close the data set:
CEMT SET FI(KSDS05) Clo
When you run the transaction VTMD, you get the following results:
08/31/11 ==> CICS VT File Definitions <== 16:24:45 Filename DIM name Org Status MStatus Operations Compare KSDS01 KSDS01 ENA INI ACT R U A B D REP N KSDS02 KSDS02 ENA INI ACT R U A B D REP N KSDS02P KSDS02AI ENA INI ACT R U A B D REP N KSDS03 KSDS03 ENA INI ACT R U A B D REP N KSDS03P1 KSDS03P1 ENA INI ACT R U A B D REP N KSDS04 KSDS04 ENA INI ACT R U A B D REP N KSDS05 KSDS05 KSDS UNE ACT R U A B D REP N KSDS05P1 KSDS05P1 ENA INI ACT R U A B D REP N KSDS05P2 KSDS05P2 ENA INI ACT R U A B D REP N KSDS05P3 KSDS05P3 ENA INI ACT R U A B D REP N KSDS05P4 KSDS05P4 ENA INI ACT R U A B D REP N KSDS06 KSDS06 ENA INI ACT R U A B D REP N KSDS06P1 KSDS06P1 ENA INI ACT R U A B D REP N KSDS07 KSDS07 ENA INI ACT R U A B D REP N KSDS07P1 KSDS07P1 ENA INI ACT R U A B D REP N KSDS08 KSDS08 ENA INI ACT R U A B D REP N KSDS09 KSDS09 ENA INI ACT R U A B D REP N KSDS10 KSDS10 ENA INI ACT R U A B D REP N More PF3=end PF7=back PF8=fwd SYSID=S650 APPLID=CICSTS32
The file definition list screen shows that KSDS05 has been changed to UNE. This means that CICS VT will not process calls for this data set because it has been disabled.
To be able to change the status of a file from a CICS perspective, the VSAM data set associated with the file control entry must exist. You can associate any VSAM data set with the file control entry providing that the file is always accessed by CICS VT.