Replacing the IPL Control-O

Operation of Control‑O involves processing phases that are implemented by starting separate Control‑O monitors, each one replacing the previous one.

Table 188 Phases for Replacing the IPL Control-O

Phase	Description
Phase 1	When Control‑O is activated with SUB=MSTR during IPL, certain functions, particularly the debugging facilities, are inactive. This is because JES is not yet initialized and it is impossible to allocate a sysout file. For this reason, Control‑O is started with parameter OUTLIST=DUMMY.
Phase 2	A simple Control‑O rule can detect the JES initialization message and then restart Control‑O without parameters. Table STARTSYS contains a sample rule that does this. The new Control‑O automatically takes control from the previous Control‑O used during IPL. It is not necessary to reload the rules.
Phase 3	If Control‑O controls the termination of JES, a third Control‑O monitor, which does not allocate sysout files, is required during shutdown of the system. This third Control‑O monitor must be started by a rule containing parameters SUB=MSTR and OUTLIST=DUMMY.

Phase

Description

Phase 1

When Control‑O is activated with SUB=MSTR during IPL, certain functions, particularly the debugging facilities, are inactive. This is because JES is not yet initialized and it is impossible to allocate a sysout file. For this reason, Control‑O is started with parameter OUTLIST=DUMMY.

Phase 2

A simple Control‑O rule can detect the JES initialization message and then restart Control‑O without parameters. Table STARTSYS contains a sample rule that does this. The new Control‑O automatically takes control from the previous Control‑O used during IPL. It is not necessary to reload the rules.

Phase 3

If Control‑O controls the termination of JES, a third Control‑O monitor, which does not allocate sysout files, is required during shutdown of the system. This third Control‑O monitor must be started by a rule containing parameters SUB=MSTR and OUTLIST=DUMMY.

Parameter TYPE of operator command START CONTROLO enables you to specify the Control‑O processing phase for a specific monitor. The following table lists the valid values for this parameter:

Table 189 Values for Parameter TYPE

Value	Description
IPL	The Control‑O monitor controls the IPL process.
REGULAR	The Control‑O monitor is a regular Control‑O monitor.
SHUTDOWN	The Control‑O monitor controls the shutdown of the system.

The Control‑O TYPE is displayed in the following initialization message:

CTO147I Control‑O INITIALIZATION COMPLETE,TYPE=type,SUB=job‑entry‑subsystem

This message can be used by Control‑O rules whenever phase‑dependent processes are handled.

Note: When Control‑O is brought up to replace an existing Control‑O monitor, it does not load rules from DD statement DARULLST. Instead, it takes control of the rules that were active under the previous Control‑O monitor. Only a new operator command F CONTROLO,O=ALL loads the rules from DARULLST.

CMEM Users:
This note also applies to CMEM rules loaded from DD statement DACTMLST.

Parent Topic

Recommended Organization Method