CEMT SET VTAM

Open or close the z/OS® Communications Server ACB, set the persistent session delay interval, or deregister CICS® from membership of a generic resource.

In the CICS Explorer, the Regions operations view provides a functional equivalent to this command.

Syntax

Note: VTAM® is now the z/OS Communications Server.
Press the Clear key to clear the screen. You can start this transaction in two ways:
  • Type CEMT SET VTAM (or suitable abbreviations for the keywords). The resulting display lists the current status, similar to that obtained by using the CEMT INQUIRE VTAM command. You can tab to the highlighted or blank fields and overtype them with the required values.
  • Type CEMT SET VTAM (or suitable abbreviations for the keywords), followed by one or more attribute settings that you want to change. For example, cemt s vt o specifies that the connection between CICS and the Communications Server is established.

Type ? at the beginning of either the first or second line to give a syntax prompt. Resetting the values takes effect immediately.

CEMT SET VTAM

Read syntax diagramSkip visual syntax diagramCEMT SET VTAMOPENCLOSEDIMMCLOSEFORCECLOSEPSDINTERVAL( hhmmss)DEREGISTERED

Options

CLOSED
The connection between CICS and the Communications Server is to end normally; that is, transactions are allowed to complete and terminals are released normally.
DEREGISTERED
Specifies that CICS is to be removed from the Communications Server generic resource of which it is currently a member. If you deregister a region from membership of a generic resource, you must end any affinities that it owns. See the PERFORM ENDAFFINITY command.

Generic resources are described in Workload balancing in a sysplex.

FORCECLOSE
The connection is stopped immediately, and all terminal connections using the Communications Server ACB (access method control block), with the transactions associated with them, are stopped abnormally. If transactions do not stop because of their state at the time FORCECLOSE was issued, you must issue CEMT SET TASK(nn) PURGE or FORCEPURGE before the ACB can be reopened.

The difference between IMMCLOSE and FORCECLOSE is that IMMCLOSE cancels any task at a Communications Server SNA logical unit (LU) and then closes the LU sessions tidily. FORCECLOSE cancels any task and closes the Communications Server ACB, closing all sessions immediately.

IMMCLOSE
The connection between CICS and the Communications Server is to be stopped immediately. Any transactions using Communications Server-connected LUs are stopped abnormally, and all such LUs are lost to CICS.

The difference between IMMCLOSE and FORCECLOSE is that IMMCLOSE cancels any task at a Communications Server SNA LU and then closes the LU sessions tidily. FORCECLOSE cancels any task and closes the Communications Server ACB, stopping all sessions immediately.

OPEN
The connection between CICS and the Communications Server is established. With ACF/Communications Server, this event occurs at the opening of the ACF/Communications Server ACB through which ACF/Communications Server communicates with CICS.

A CEMT SET VTAM OPEN command fails with a STILL CLOSING message if the command is issued while a previous predatory takeover is still being processed. No attempt is made to open the Communications Server ACB, because it is still being closed because of the predatory takeover. After the predatory takeover completes, the CEMT SET VTAM OPEN command works as usual. The failure is notified by a RESP=INVREQ and RESP2=14 condition.

If CICS is using Communications Server multinode persistent sessions, and the Communications Server has been restarted after an abend, opening the Communications Server ACB causes CICS to restore the persistent sessions that the Communications Server has retained. However, CICS does not restore APPC synclevel 2 sessions, which are unbound.

PSDINTERVAL (hhmmss)
Specifies the persistent session delay interval, expressed in the form hhmmss. It specifies if and for how long Communications Server sessions are held in recovery pending state in the event of a failure. The permitted range is 000000 to 235959 inclusive.
000000
If a failure occurs, sessions are ended. This value is the default, and means that persistent sessions support is not exploited.
HHMMSS
Sessions are held in recovery pending state by the Communications Server for up to the interval specified.

Table 1 shows possible CEMT error messages resulting from unsuccessful attempts to set the persistent session delay interval. The listing of RESP2 values for the EXEC CICS SET VTAM command explains the meaning of these messages in more detail.

Table 1. CEMT error messages for attempts to set the persistent session delay interval
Message RESP/RESP2
INVALID PSDINT RESP=INVREQ, RESP2=4
NOT WITH XRF RESP=INVREQ, RESP2=8
SETLOGON FAILURE RESP=INVREQ, RESP2=9
BACK LEVEL VTAM RESP=INVREQ, RESP2=10
ACB CLOSED RESP=INVREQ, RESP2=12
NOT WITH PSTYPE=NOPS RESP=INVREQ, RESP2=22
RECOVERY ERROR All other cases of INVREQ