SNAX Creator-2 Configuration and Control Manual

Subsystem Control Facility
Introduction to SCF for SNAX Creator-2
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Some SCF commands include an optional SEL parameter that selects only objects that
are (or are not) in a particular object state. The SEL parameter has the following
syntax:
SEL [NOT] state
When the SEL option is used without the NOT keyword, the command affects only
those objects that are in the specified state. When the SEL option is used with the NOT
keyword, the command affects only those objects that are not in the specified state.
For example, the following command deletes only those SU objects that begin with the
characters $CREA.#SNA and that are in the STOPPED state:
DELETE SU $CREA.#SNA*, SEL STOPPED
Object Attributes
Attributes are the named, configurable characteristics of the objects. Attributes are
specified as parameters to the ADD, ALTER, and INFO commands. For example,
TEXT is an attribute of an ENTRY object. The attributes for SNAX Creator-2 objects
are described in Section 5, “Attributes and Expressions for SNAX Creator-2.”
How SCF Works SCF performs most commands in the following sequence:
1. When SCF receives a command, it interprets the command and performs the
necessary steps to execute it. Some commands can be handled by SCF with no
interaction with SCP (for example, OUT).
2. If the command involves control or configuration of a subsystem object or a
request for information about an object, SCF produces a message that describes the
object and the operation to be performed on it. This message is then sent to a
subsystem process through SCP. A single command might require several
messages before the operation can be completed; the exact number of steps
required to execute a command varies from command to command.
3. When the subsystem process has processed the message, it returns a completion
message (one or more messages, if the command is a request for information about
an object) to SCF through SCP. SCF displays the requested information, if any,
and then displays its prompt and waits for the next command. If the completion
message indicates an error condition, SCF displays an appropriate message and
then displays its prompt.
Running SCF SCF resides in a file called $SYSTEM.SYSTEM.SCF. To start SCF, use the TACL RUN
command. SCF can be run in either of two modes: interactive or noninteractive. For
more information about the syntax of the RUN command and these two modes of
operation, see the Subsystem Control Facility (SCF) Reference Manual.