Now lets proceed further with AS400 Subsystem. What is a Subsystem?
The subsystem is where work is processed on the system. A subsystem is a single, predefined operating environment through which the system coordinates the work flow and resource use. The system can contain several subsystems, all operating independently of each other. Subsystems manage resources.
All jobs, with the exception of system jobs, run within subsystems. Each subsystem can run unique operations. For instance, one subsystem may be set up to handle only interactive jobs, while another subsystem handles only batch jobs. Subsystems can also be designed to handle many types of work. The system allows you to decide the number of subsystems and what types of work each subsystem will handle.
The run-time characteristics of a subsystem are defined in an object called a subsystem description. For example, if you want to permanently change the amount of work (number of jobs) coming from a job queue into a subsystem you only need to change the job queue entry in the subsystem description.
What is Controlling Subsystem?
The controlling subsystem is the interactive subsystem that starts automatically when the system starts, and it is the subsystem through which the system operator controls the system via the system console. It is identified in the Controlling subsystem (QCTLSBSD) system value.
IBM supplies two complete controlling subsystem descriptions: QBASE (the default controlling subsystem) and QCTL. Only one controlling subsystem can be active on the system at any time.
It is required to bring the system to restricted state to perform certain tasks. The system must be in this condition for commands such as Save System (SAVSYS) or Reclaim Storage (RCLSTG) to run. This is required before IPL and applying patch or PTF's. Some programs for diagnosing equipment problems also require the system to be in a restricted condition. To end this condition, you must start the controlling subsystem again. The Controlling subsystem would start the system up as normal.
Note: There is also a batch restricted state in which one batch job can be active.
When all of the subsystems, including the controlling subsystem are ended, a restricted condition is created. You can end each subsystem individually or you can use the ENDSBS SBS(*ALL) OPTION(*IMMED).
Important: Before, you end the subsyetm, it is good to ensure your own job is running under QCTL. This can be done by TRFJOB QCTL. When you are logged in using console, it automatically starts your job under QCTL subsystem. The system cannot reach the restricted state until there is only one job remaining in the controlling subsystem. Sometimes it may appear as though there is a single job remaining, but the system does not go into the restricted state. In this case you need to verify that there are no suspended system request jobs, suspended group jobs, or disconnected jobs on the remaining active display. Use the Work with Active Jobs (WRKACTJOB) command and press prompt F14=Include to display any suspended or disconnected jobs. If these jobs exist, you need to end them in order for the system to reach the restricted state. The ENDSYS and ENDSBS functions will send a CPI091C information message to the command issuer when this condition is detected.
What is Subsystem Description?
The run-time characteristics of a subsystem are defined in an object called a subsystem description. For example, if you want to permanently change the amount of work (number of jobs) coming from a job queue into a subsystem you only need to change the job queue entry in the subsystem description.
A subsystem description is a system object that contains information defining the characteristics of an operating environment controlled by the system. The system-recognized identifier for the object type is *SBSD. A subsystem description defines how, where, and how much work enters a subsystem, and which resources the subsystem uses to perform the work. An active subsystem takes on the simple name of the subsystem description.
Like a set of detailed blueprints, each subsystem description is unique, containing the specific characteristics that describe the subsystem. The description includes where work can enter the subsystem, how much work the subsystem can handle, how much main storage (memory) will be used, and how quickly jobs in the subsystem can run.
You can use a subsystem description supplied with your system (with or without making changes to it), or you can create your own.
The subsystem is where work is processed on the system. A subsystem is a single, predefined operating environment through which the system coordinates the work flow and resource use. The system can contain several subsystems, all operating independently of each other. Subsystems manage resources.
All jobs, with the exception of system jobs, run within subsystems. Each subsystem can run unique operations. For instance, one subsystem may be set up to handle only interactive jobs, while another subsystem handles only batch jobs. Subsystems can also be designed to handle many types of work. The system allows you to decide the number of subsystems and what types of work each subsystem will handle.
The run-time characteristics of a subsystem are defined in an object called a subsystem description. For example, if you want to permanently change the amount of work (number of jobs) coming from a job queue into a subsystem you only need to change the job queue entry in the subsystem description.
What is Controlling Subsystem?
The controlling subsystem is the interactive subsystem that starts automatically when the system starts, and it is the subsystem through which the system operator controls the system via the system console. It is identified in the Controlling subsystem (QCTLSBSD) system value.
IBM supplies two complete controlling subsystem descriptions: QBASE (the default controlling subsystem) and QCTL. Only one controlling subsystem can be active on the system at any time.
It is required to bring the system to restricted state to perform certain tasks. The system must be in this condition for commands such as Save System (SAVSYS) or Reclaim Storage (RCLSTG) to run. This is required before IPL and applying patch or PTF's. Some programs for diagnosing equipment problems also require the system to be in a restricted condition. To end this condition, you must start the controlling subsystem again. The Controlling subsystem would start the system up as normal.
Note: There is also a batch restricted state in which one batch job can be active.
When all of the subsystems, including the controlling subsystem are ended, a restricted condition is created. You can end each subsystem individually or you can use the ENDSBS SBS(*ALL) OPTION(*IMMED).
Important: Before, you end the subsyetm, it is good to ensure your own job is running under QCTL. This can be done by TRFJOB QCTL. When you are logged in using console, it automatically starts your job under QCTL subsystem. The system cannot reach the restricted state until there is only one job remaining in the controlling subsystem. Sometimes it may appear as though there is a single job remaining, but the system does not go into the restricted state. In this case you need to verify that there are no suspended system request jobs, suspended group jobs, or disconnected jobs on the remaining active display. Use the Work with Active Jobs (WRKACTJOB) command and press prompt F14=Include to display any suspended or disconnected jobs. If these jobs exist, you need to end them in order for the system to reach the restricted state. The ENDSYS and ENDSBS functions will send a CPI091C information message to the command issuer when this condition is detected.
What is Subsystem Description?
The run-time characteristics of a subsystem are defined in an object called a subsystem description. For example, if you want to permanently change the amount of work (number of jobs) coming from a job queue into a subsystem you only need to change the job queue entry in the subsystem description.
A subsystem description is a system object that contains information defining the characteristics of an operating environment controlled by the system. The system-recognized identifier for the object type is *SBSD. A subsystem description defines how, where, and how much work enters a subsystem, and which resources the subsystem uses to perform the work. An active subsystem takes on the simple name of the subsystem description.
Like a set of detailed blueprints, each subsystem description is unique, containing the specific characteristics that describe the subsystem. The description includes where work can enter the subsystem, how much work the subsystem can handle, how much main storage (memory) will be used, and how quickly jobs in the subsystem can run.
You can use a subsystem description supplied with your system (with or without making changes to it), or you can create your own.
The Subsystem description has normal parameters. The two important parameters while creating a new subsystem are Work entries and Routing entries.
Work entries identify the sources where jobs can enter a subsystem. Specific types of work entries are used for different types of jobs. Work entries are part of the subsystem
description.
The routing entry identifies the main storage subsystem pool to use, the controlling program to run (typically the system-supplied program QCMD), and additional run-time information (stored in the class object). Routing entries are stored in the AS400 subsystem description.
Thank You Sharmistha. I recently took a lateral movement and joined AS/400 as a computer operator. What is your recommendation with regards to 'growth' on this platform?
ReplyDeleteWhere are you located, you work with IBM?
ReplyDeletegood information Sharmistha
ReplyDelete