Safeguard Management Programming Manual (G06.29+, H06.08+, J06.03+)

Glossary
Safeguard Management Programming Manual—422086-028
Glossary-3
context-sensitive server
context-sensitive server. A server that retains information about previous processing. For
instance, in performing a command on a list of objects, a context-sensitive subsystem
might retain, between response messages, the name of the object it last processed.
Context-sensitive servers limit or complicate the requester’s ability to interrupt or
abandon the continuation of a series of response messages.
context token. A token that indicates (by its presence or absence) whether or not there are
more response messages to come. If this token is present in a response message to a
command, the response is continued in another response message. To obtain the next
message, the application program reissues the original command with one
modification: the context token is included in the new command message. When the
subsystem sends a response message that does not contain a context token, the
application program knows that the series of response messages is complete. The
application program does not need to be concerned with the contents of the context
token. These are for the benefit of the subsystem, so that it can “find its place” and
issue the next response message. In a response to a command, the context token is a
kind of response-control token. It is the only response-control token that can be
present in a response as well as in a command. (See context and response-control
token.) In event-message distribution, the GETEVENT command returns the context
token along with the next event message. The context token identifies the following
event message so that the backup distributor process can recover if the primary
process goes down. The requester must send the context token back to the distributor
on the next call to GETEVENT. See context, context information.
continuation. The packaging of a response in multiple response messages. The subsystem
uses a context token to indicate that the response is continued to another message.
Each response message can contain multiple response records, but a single response
record cannot span two response messages.
control and inquiry. The aspects of object management related to the state or
configuration of an object. Such aspects include actions that affect the state or
configuration of an object, inquiries about the object, and commands pertaining to the
session environment (for example, commands that set default values for the session).
See also event management
.
control operation. An action that affects the recording, processing, transmission, or
interpretation of data. In SPI, an operation that modifies the contents of an SPI buffer
not by adding a token, but by performing a housekeeping function; for instance,
clearing the last SPI error number or flushing the buffer from the current position. A
positioning operation is one kind of control operation.
critical event. An event that has been designated as critical to the operation of the system
or network. Each subsystem determines what set of events generated by that
subsystem should be designated as critical. The subsystem identifies whether an event
is critical or noncritical by setting the value of the emphasis token in the event
message. See also noncritical event
.