gtpm6m0c | Main Supervisor Reference |
The state change process is known as cycle-up when system
resources and functions are being activated and cycle-down when
system resources and functions are being deactivated. During cycle-up,
additional resources and functions are made available in successively higher
system states, until all resources are available. There are
5 system states cycled up in the following ascending order:
- 1052 state
- Utility state
- CRAS (computer room agent set) state
- Message switching state
- Norm state.
You can change system states with the ZCYCL command and display
the system state with the ZDSYS command. See TPF
Operations for detailed information on the functions available in each
state.
- Note:
- Application programmers should consider the services and functions that are
operational during a particular system state when designing application
programs.
1052 state is the lowest system state. Most system
services are inactive. Services active during 1052 state include:
- Commands from the system console or 3270 local devices logged into the
system message processor. 3270 devices must have their addresses in the
CRAS status table (CRAT).
- Keypoint update.
Utility state can be entered only from 1052 state. Thus,
the system must be returned to 1052 state from any other state (CRAS, message
switching, or norm) before utility state can be entered. Utility state
services include:
- Commands from CRAS terminals
- The real-time clock (which is adjusted to compensate for time spent in
1052 state)
- Time-initiated entries
- Keypoint update
- Disk lost interrupt
- Tape lost interrupt
- Interrupts from 3270 local devices (but messages are rejected if the
terminal is not logged into the system message processor).
In CRAS state, all of the services active during utility state
are active, as well as the following services:
- All messages are accepted, but only from CRAS terminals. All other
terminals receive a response of: SYSTEM RESTRICTED. RETRY
IN 5 MIN.
- The GFS (get file storage) facility is available. You can issue
GETSC, GETLC, and RELFC macros. See TPF General
Macros.
- All active high-speed and BSC communication lines are polled.
Synchronous link control (SLC) is active.
Message switching state is similar to CRAS state, with the
following exceptions:
- All non-SDLC (Synchronous Data Link Control) lines are active.
- Only message switching entries are processed. All other entries are
either rejected or queued for later processing.
Norm or normal state allows the activation of all system and
application services and functions. All entries are allowed in norm
state.
- The time available supervisor (TAS) is active.
- Catastrophic error recovery is attempted.
- Polling of the Network Control Program (NCP) can be started.