Milestone 10: Enabling CICS support

If your site is not using—and does not plan to use—Xchange's CICS support, skip this milestone and continue with Milestone-11-Enablling-Db2-support.

The roles involved are: Xchange Installer.

This milestone contains tasks for enabling Xchange's CICS transaction support and CICS region support.

• You can exchange the date and time for a CICS region using Xchange's CICS region support feature.
• You can exchange the date and time for individual programs, terminals, user IDs, and transactions within a CICS region using Xchange's CICS transaction support feature.
  
  

Task 10.1: Enabling CICS transaction support

If your site does not require CICS transaction support, skip this step and continue with Task-10-2-Enable-CICS-region-support.

You can exchange the date and time for individual programs, terminals, user IDs, and transactions within a CICS region using Xchange's CICS transaction support feature.

1. Add the load library CPWR.MLXGnnn.SLXGLOAD containing Xchange to the DFHRPL concatenation in your site's CICS startup JCL.
2. Use Resource Definition Online (RDO) to update your site's CICS tables with CEDA transactions, either one at a time or using the RDO batch utility. For CICS TS 3.1 and above, use member XGCRDOTE in the CPWR.MLXGnnn.SLXGDATA library as your RDO batch utility input data set. Make any necessary changes, then either submit your RDO batch utility JCL to batch the required CEDA transactions, or run the transactions individually.

Task 10.1.1: Enabling Automatic Request Deletion

Normally, an Xchange user will delete their requests before leaving CICS. But if a terminal is disconnected, signed off, or logged off while an Xchange session is still active, the ID of that terminal will remain assigned to the abandoned (but still active) requests. Because another terminal logging on could be assigned the same ID, it is possible for a user to be assigned active Xchange requests they don't know about. The first user may have left the session with requests set and no sure way of re- accessing the same session to delete them.

To prevent this from happening, Xchange can be set up to automatically delete requests when the terminal is signed off, logged off, and/or disconnected. This is done by modifying the exit DFHZATDX or whatever terminal autoinstall exit is being used. Then when a terminal is logged off, the modified exit will delete any Xchange requests owned by that terminal.

Enable automatic request deletion as follows:

1. Locate the exit DFHZATDX (or the VTAM terminal autoinstall exit used at your site) for modification. If your site uses a different autoinstall exit, its name can be found in the SIT parameter AIEXIT.

2. Add the following line of code to DFHZATDX in the Delete Processing Section after the IBM "Put Delete Code" Here comment:
   EXEC CICS START INTERVAL (0) TRANSID ('XGTM') FROM (DELETE_TERM_ID)

   Tip

   Consider adding NOHANDLE—or other appropriate condition handling—for exception conditions such as TRANSIDERR.

3. If your site uses MRO, additional lines of code are required for each application owning region (AOR) where Xchange is installed. The lines should be added directly after the line shown above. 
   Select the lines appropriate for your site from the following:

   EXEC CICS START INTERVAL (0)                                      *
       TRANSID(’XGTn’) FROM(DELETE_TERM_ID) NOHANDLE

   where XGTn is the terminal owning region (TOR) transaction ID for XGTM in the AOR

   EXEC CICS START INTERVAL (0)                                      *
       TRANSID(’XGTM’) SYSID(’aor-id’) FROM(DELETE_TERM_ID) NOHANDLE

   where aor-id is the SYSID of the AOR

   Important

   A continuation character must be included in position 72 of the first line, as shown

4. Reassemble and link edit DFHZATDX.

Task 10.1.2: Specify Program and Transaction Exclusions

Xchange is designed to exclude certain default programs and transactions from date and time exchanges. You can specify additional programs or transactions by editing program XGTEXCL found in the CPWR.MLXGnnn.SLXGDATA PDS. Excluding a program or transaction does not prevent a user from specifying it in a request. When a match for the specified program or transaction is encountered, Xchange returns the actual date and time rather than substituting a value.

1. Add an XGTXCLP entry for each program to be excluded and an XGTXCLT entry for each transaction to be excluded. The XGTXCLP entry is required whenever either entry is added and must always precede the XGTXCLT entry. An asterisk wildcard character can be used to create generic program or transaction entries as shown in this example:

   XGTXCLP 'PROG*'
   XGTXCLT 'TRN*'

2. When no programs but one or more transactions are to be excluded, be sure to include the XGTXCLP entry as shown here:

   XGTXCLP
   XGTXCLT 'TRN*'

3. When no transactions but one or more programs are to be excluded, be sure to include the XGTXCLT entry as shown here:

   XGTXCLP
   'PROG*' XGTXCLT
4. After adding the desired entries, perform the following:
   1. Assemble XGTEXCL
   2. Relink XGTMAIN and XGTSEQI
   3. Newcopy XGTMAIN and XGTSEQI
   4. STOP Xchange CICS interface - STOP primary command on XGTS line
   5. Enter XGTS/XGTM to restart CICS Xchange interface
      Sample JCL for assembling XGTEXCL and relinking XGTMAIN and XGTSEQI is provided in CPWR.MLXGnnn.SLXGCNTL PDS member ASMXCL.

Task 10.1.3: Enabling PLT Initialization

You may use PLT initialization to enable Xchange CICS transaction support and set Xchange CICS transaction support requests as follows:

1. To enable Xchange PLT initialization, add:

   DFHPLT TYPE=ENTRY,PROGRAM=XGTSEQI

   to your PLTPI table, placing it after the DFHDELIM entry.

2. Define a PDS or PDSE for DD XGSEQINP to hold DXchange CICS transaction support requests with the following attributes:
   1. Record format: FB
   2. Record length: 80.
      Sample JCL to define a PDS or PDSE is provided in CPWR.MLXGnnn.SLXGCNTL PDS member DEFSEQI.
3. Create records in the input data set as described in Using-CICS-Transaction-Support-with-Input-from-a-PDS-or-PDSE.
4. Add the input DD name to your site’s CICS startup JCL as described in Using-CICS-Transaction-Support-with-Input-from-a-PDS-or-PDSE.

Task 10.1.4: Enable PLT Shutdown

You may use the CICS PLT shutdown to free up the storage used for Xchange requests and messages. If program XGTMAIN is included in your PLT shutdown table, all Xchange requests and messages will be deleted, and their storage freed, when the CICS region is brought down.

To enable Xchange PLT shutdown, add this code to your PLTSD table, placing it before the DFHDELIM entry.

Task 10.2: Enable CICS region support

If your site does not require CICS region support, skip this step and continue with Milestone-11-Enablling-Db2-support.

Using STCKSYNC support

STCKSYNC support is required with CICS region support. The activation of STCKSYNC support is done during the startup of Xchange. By enabling the Xchange SVC, you also enable STCKSYNC support. See Milestone-7-Enabling-Xchange-SVCs for additional information.

Task 10.2.1: Enable PLT initialization

Due to the way in which the CICS ABSTIME value is returned, Xchange must be started in the PLT.

Enable Xchange PLT initialization as follows:

1. Add the following to your PLTPI table, placing it after the DFHDELIM entry:

   DFHPLT TYPE=ENTRY,PROGRAM=XGTREGN
2. Use Resource Definition Online (RDO) to update your site's CICS tables with CEDA transactions in member XGCRDOR of data set CPWR.MLXGnnn.SLXGDATA, either one at a time or using the RDO batch utility.
3. Copy load modules XGTREGN and XGTABSTM from data set CPWR.MLXGnnn.SLXGLOAD to a load library in the DFHRPL of your site's CICS startup JCL.

Task 10.2.2: Enable midnight rollover

Xchange's CICS region support requires additional midnight rollover processing. To enable this support, perform the following steps:

1. Add the following line to your PLTPI table after the DFHDELIM entry:

   DFHPLT TYPE=ENTRY,PROGRAM=XGTAJP3

   Important

   If you completed Task-10-1-Enable-CICS-transaction-support, you may skip steps 2, 3 and the following.

2. Add the load library CPWR.MLXGnnn.SLXGLOAD containing Xchange to the DFHRPL concatenation in your site's CICS startup JCL. 
3. Use Resource Definition Online (RDO) to update your site's CICS tables with CEDA transactions, either one at a time or using the RDO batch utility. For CICS TS 3.1 and above, use member XGCRDOTE in the CPWR.MLXGnnn.SLXGDATA library as your RDO batch utility input data set. Make any necessary changes, then either submit your RDO batch utility JCL to batch the required CEDA transactions, or run the transactions individually.