Connecting to DBCTL: overview

You can perform CICS® and DBCTL startup from a TSO terminal or an MVS™ console.

About this task

Before DBCTL can begin accepting transactions, several things must happen, as shown in Figure 1. The numbers in the figure and corresponding step numbers indicate the sequence of events.
Figure 1. Connecting to DBCTL
The sequence of events is described fully in the list that follows.
  1. CICS is started by submitting a job or starting a procedure, as described in CICS actions on an initial start.
  2. DBCTL is started by submitting a job or starting a procedure, as described in Starting DBCTL, DLISAS, and DBRC.
  3. After receiving a DBCTL READY message, indicating that startup is complete, the IMS console operator enters a start command, as follows:
    • If starting DBCTL for the first time, use /NRESTART CHECKPOINT 0 FORMAT ALL. This command performs a cold start of DBCTL and formats the write ahead data set (WADS) and the restart data set (RDS).
    • /NRESTART for a warm start.
    • /ERESTART for an emergency restart after a failure.

    The / used in these commands is explained in Operator communication with DBCTL: overview. See Restarting DBCTL for information about restart options.

    When the start has completed, the following message is issued: 
    DFS994I rtype START COMPLETED
    where rtype is the type of start requested (COLD, WARM, or EMERGENCY).
  4. The CICS operator requests connection to DBCTL using the CDBC transaction.

Step 1 can be done before, during, or after steps 2 and 3. Steps 2 and 3 must be done in the sequence described, and all three steps must be completed successfully before step 4 can begin.

The previous steps show you how to manually start IMS. IMS can also be started and restarted automatically; for more details, see System administration in IMS product documentation.