Subsystems shipped with the system
Two complete subsystem configurations are supplied by IBM® and can be used without being changed.
The configuration the system uses when the system is started is controlled by the Controlling subsystem/library (QCTLSBSD) system value. The default configuration consists of the following subsystem descriptions:
| Subsystem | Description |
| Qbase (controlling subsystem) | Qbase supports interactive, batch, and communications jobs. It has an autostart job, which automatically starts the Qusrwrk, Qserver, and Qspl subsystems. |
| Qserver | This is the file server subsystem. |
| Qspl | This is the spool subsystem that supports reader and writer jobs. |
| Qsyswrk | This is the system work subsystem. It contains jobs that support system functions that are started automatically at system startup and when the system comes out of restricted state. |
| Qusrwrk | This is the user work subsystem. It contains jobs that are started by servers to do work on behalf of a user. |
The other configuration, which is supplied by IBM, consists of the following subsystem descriptions:
| Subsystem | Description |
| Qctl (controlling subsystem) | Qctl has an autostart job, which automatically starts the Qinter, Qbatch, Qcmn, Qusrwrk, Qserver and Qspl subsystems. |
| Qinter | This is the subsystem that supports interactive jobs, except those at the console. |
| Qbatch | This is the subsystem that supports batch jobs. |
| Qcmn | This is the subsystem that supports communications jobs, excluding TCP/IP communications jobs. These communications jobs are necessary for various communications protocols that the IBM i system supports. |
| Qserver | This is the file server subsystem. |
| Qspl | This is the spool subsystem that supports reader and writer jobs. |
| Qsyswrk | This is the system work subsystem. It contains jobs that support system functions that are started automatically at system startup and when the system comes out of restricted state. |
| Qusrwrk | This is the user work subsystem. It contains jobs that are started by servers to do work on behalf of a user. |
The Qbase configuration gives the ability to run all of the same functions that you can run with the Qctl configuration and is easier to manage because it consists of fewer subsystems.
The Qctl default configuration allows for more individualized control over your system operations by dividing the system activity into different subsystems based on the type of activity. For example, if you want to run batch jobs over the weekend, but do not want anyone to be able to sign on (except at the console), you can easily do that with the Qctl configuration by ending the Qinter subsystem.
If you are considering creating your own subsystem configuration, you might also find that it is easier to use the Qctl configuration as a starting point than the Qbase configuration.