The System Resource Controller (SRC) provides a set of commands and subroutines to make it easier for the system manager and programmer to create and control subsystems. A subsystem is any program or process or set of programs or processes that is usually capable of operating independently or with a controlling system. A subsystem is designed as a unit to provide a designated function.
The SRC was designed to minimize the need for operator intervention. It provides a mechanism to control subsystem processes using a common command line and the C interface. This mechanism includes the following:
The SRC is useful if you want a common way to start, stop, and collect status information on processes.
A subsystem can have one or more of the following properties:
A few subsystem examples are ypserv, ntsd, qdaemon, inetd, syslogd, and sendmail.
Note: Refer to each specific subsystem for details of its SRC capabilities.
Use the lssrc -a command to list active and inactive subsystems on your system.
A subsystem group is a group of any specified subsystems. Grouping subsystems together allows the control of several subsystems at one time. A few subsystem group examples are TCP/IP, SNA Services, Network Information System (NIS), and Network File Systems (NFS).
A subserver is a program or process that belongs to a subsystem. A subsystem can have multiple subservers and is responsible for starting, stopping, and providing status of subservers. Subservers can be defined only for a subsystem with a communication type of IPC message queues and sockets. Subsystems using signal communications do not support subservers.
Subservers are started when their parent subsystems are started. If you try to start a subserver and its parent subsystem is not active, the startsrc command starts the subsystem as well.
The System Resource Controller has a hierarchical structure (see figure). The hierarchy begins with the operating system followed by a subsystem group (such as tcpip), which contains a subsystem (such as the inetd daemon), which in turn can own several subservers (such as the ftp daemon and the finger command).
|Starts the System Resource Controller.|
|Starts a subsystem, subsystem group, or subserver.|
|Stops a subsystem, subsystem group, or subserver.|
|Refreshes a subsystem.|
|Turns on tracing of a subsystem, a group of subsystems, or a subserver.|
|Turns off tracing of a subsystem, a group of subsystems, or a subserver.|
|Gets status on a subsystem.|