IBM SC34-7012-01 Start requests, Terminal control resources, CSD-defined resource definitions

Start requests

In general, start requests are recovered only when they are associated with recoverable data or are protected and the issuing unit of work is indoubt.

However, recovery can be further limited by the use of the specific COLD option on the system initialization parameter for TS, ICP, or BMS. If you suppress start requests by means of the COLD option on the appropriate system initialization parameter, any data associated with the suppressed starts is discarded. The rules are:

vICP=COLD suppresses all starts including BMS starts.

vTS=COLD (or TS main only) suppresses all starts that had data associated with them.

vBMS=COLD suppresses all starts relating to BMS paging.

Start requests that have not been suppressed for any of the above reasons either continue to wait if their start time or interval has not yet expired, or are processed immediately.

For start requests with terminals, consider the effects of the CICS restart on the set of installed terminal definitions. For example, if the terminal specified on a start request is no longer installed after the CICS restart, CICS invokes an XALTENF global user exit program (if enabled), but not the XICTENF exit.

Terminal control resources

Terminal control information is installed from the warm keypoint in the global catalog, or installed from the TCT, depending on whether the definitions are CSD-defined or TCT-defined.

CSD-defined resource definitions

CICS retrieves the state of the CSD-eligible terminal control resources from the catalog entries that were written:

vDuring a previous cold start

vWhen resources were added with EXEC CICS CREATE or CEDA INSTALL

vWhen resources were added with autoinstall (subject to the AIRDELAY system initialization parameter)

vRewritten to the catalog at an intervening warm shutdown

The state of the catalog may have been modified for some of the above resources by their removal with a CEMT, or an EXEC CICS DISCARD, command.

CICS uses records from the system log, written when any terminal resources were being updated, to perform any necessary recovery on the cataloged data. This may be needed if terminal resources are installed or deleted while CICS is running, and CICS fails before the operation is completed.

Some terminal control resources are installed or deleted in “installable sets” as described under “Committing and cataloging resources installed from the CSD” on page 49. If modifications are made to terminal resource definitions while CICS is running, CICS writes the changes in the form of forward recovery records to the system log. If the installation or deletion of installable sets or individual resources

64CICS TS for z/OS 4.1: Recovery and Restart Guide