Envoy Application Programming Manual

Glossary
Envoy Application Programming Manual—427159-001
Glossary-8
sensitive command.
sensitive command. One that can be issued only by a user with super-group access, by the
owner of the subsystem, or by a member of the group of the owner of the subsystem. For
Compaq communications subsystems, the sensitive commands can change the state or
configuration of objects, start or stop tracing, or change the values of statistics counters.
See also nonsensitive command.
server. (1) An implementation of a system used as a stand-alone system or as a node in an
Expand network. (2) A combination of hardware and software designed to provide
services in response to requests received from clients across a network. For example, the
NonStop™ Himalaya range of servers provides transaction processing, database access,
and other services. (3) A process or program that provides services to a client or a
requester. Servers are designed to receive request messages from clients or requesters;
perform the desired operations, such as database inquiries or updates, security
verifications, numerical calculations, or data routing to other computer systems; and
return reply messages to the clients or requesters. A server process is a running instance
of a server program.
ServerNet LAN systems access (SLSA) subsystem. A subsystem of the Compaq
NonStop™ Kernel operating system for configuration and management of ServerNet
local area network (LAN) objects in G-series releases.
ServerNet WAN (SWAN) concentrator. A six-port communications line concentrator that
provides connectivity to a NonStop™ Himalaya S-series server. The SWAN
concentrator supports both synchronous and asynchronous data over RS-232, RS-449,
X.21, and V.35 electrical and physical interfaces. It replaces all of the earlier WAN
controllers, such as the 3604, 3605, 3650, and the 6100 communications controllers.
SLSA subsystem. See ServerNet LAN systems access (SLSA) subsystem
.
SPI. See Subsystem Programmatic Interface (SPI).
subsystem. (1) A secondary or subordinate system, usually capable of operating
independently of or asynchronously with a controlling system. (2) A program or set of
processes that manages a cohesive set of Subsystem Control Facility (SCF) objects.
Each subsystem has a manager through which applications can request services by
issuing commands defined by that subsystem.
Subsystem Control Facility (SCF). A part of DSM, it is used to provide a common,
interactive management interface for configuring, controlling, and collecting
information from Compaq data communications products.
Subsystem Control Point (SCP). The message router for all Subsystem Control Facility
(SCF) subsystems. There can be several instances of this process. Using the Subsystem
Programmatic Interface (SPI), applications send each command for a subsystem to an
instance of this process, which in turn sends the command to the manager process of the
target subsystem. SCP also processes a few commands itself. It provides security
features, version compatibility, support for tracing, and support for applications
implemented as process pairs.