OSI/FTAM Programming Reference Manual

Glossary
HP NonStop OSI/FTAM Programming Reference Manual—528611-001
Glossary-27
subdevice.
subdevice. A logical entity maintained by a NonStop subsystem to provide access to a
physical connection—that is, to a communications line. There might be one or many
subdevices associated with a given line or process. Exactly what constitutes a
subdevice differs depending on the subsystem. In OSI subsystems, a subdevice allows
communication between a process at a particular OSI layer, such as an FTAM initiator
or responder, and the local NonStop OSI server process (TAPS, TSP, or NSP) that
provides the services of the next lower layer. Each initiator subdevice handles one
association or (at layers below ACSE) one connection. Each responder subdevice
handles one attach, which is used to establish an association requested by a remote
application.
A NonStop FTAM initiator subdevice is created dynamically when an association is
established and usually lasts only as long as the association exists. A NonStop FTAM
responder subdevice is created when the responder issues an attach.
subsystem. (1) A term that generally defines the NonStop software or hardware facilities
that provide users with access to a set of services and other resources. (2) In the
context of DSM, a program or set of processes that manages a cohesive set of objects.
Each subsystem has a process through which applications can request services by
issuing commands defined by that subsystem; in some cases, this process is the entire
subsystem. Many subsystems also have interactive interfaces.
Subsystem Control Facility. See SCF (Subsystem Control Facility).
Subsystem Control Point. See SCP (Subsystem Control Point).
Subsystem Programmatic Interface. See SPI (Subsystem Programmatic Interface).
subtree. A part of a tree comprising an arbitrary node as the subtree root node and all the
other nodes that can be reached by a path from this subtree root node. See tree.
summary state. A DSM state. See state. (definition 2).
summary-state transition. See state transition.
super group. The set of NonStop operating system users whose group ID is 255. User IDs
within the super group confer implicit authorizations not available to other users,
including the ability to run sensitive SCF commands.
super ID. The NonStop user ID represented by the pair of numbers (255,255). The local
super ID is the group manager for the super group. By default, the super ID can run
any command without restriction.
supported file attribute. A virtual filestore (VFS) file attribute that can be referenced or
modified. Contrast with partially supported file attribute.
swap disk. See swap volume.