IBM 3174 Reference Manual page 212

printer authorization matrix (PAM). A matrix stored In
the controller that establishes printer assignment and
classification.
private branch exchange (PBX). An automatic or
manual private telephone exchange for transmission of
calls to and from the public telephone network.
program access (PA) key. On a display device
keyboard, a key that produces a call to a program that
performs display operations. See also program
function (PF) key.
program function (PF) key. On a display device
keyboard, a key that passes a signal to a program to
call for a particular display operation. See also
program access (PA) key.
programmable symbols (PS). Customer-defined
symbols. There are a maximum of 190 symbols In a
programmed symbol set.
programmed symbol set (PSS). A set of fonts that can
be system-defined or defined by the user and to which
a code can be assigned.
programmed symbols (PS). In the 3270 Information
DisplaySystem, an optional feature that stores up to six
user-definable, program-loadable character sets of 190
characters each In terminal read/write storage for
display or printing by the terminal.
protected field. (1) In word processing, preset data or
an area that cannot be changed or overridden by an
operator without altering the program. (2) On a display
device, a display field In which a user cannot enter,
modify, or erase data. Contrast with unprotected field.
protocol. (1) A set of semantic and syntactic rules that
determine the behavior of functional units In achieving
communication. (2) In SNA, the meanings of and the
sequencing rules for requests and responses used for
managing the network, transferring data, and
synchronizing the states of network components.
register. A storage device having a specified storage
capacity such as a bit, byte, or computer word, and
usually Intended for a special purpose.
remote. Pertaining to a system, program, or device
that Is accessed through a telecommunication line.
Response Time IMonitor (RIM). A network
management tool that measures and records the
transaction times of Inbound host attention (AID)
operations from display stations that communicate with
the host.
selector pen. A pen-like Instrument that can be
attached to a display station. When a program using
full-screen processing Is assigned to the display
station, the pen can be used to select items on the
screen or to generate an attention. Synonym for light
pen.
session. (1) In network architecture, an association of
facilities necessary for establishing, maintaining, and
releasing connections for communication between
stations. (2) In MLT, synonymous with logical terminal
(LT). (3) In SNA, a logical connection between two
network addressable units that can be activated,
tailored to provide various protocols, and deactivated
as requested.
session limit. In 3174, the total number of logical
terminals or defined AEA default destinations for an
AEA port set.
simulate. (1) To represent certain features of the
behavior of a physical or abstract system by the
behavior of another system; for example, to represent a
physical phenomenon by means of operations
performed by a computer or to represent the
operations of a computer by those of another computer.
(2) To Imitate one system with another, primarily by
software, so that the imitating system accepts the same
data, executes the same computer programs, and
achieves the same results as the Imitated system.
(3) Contrast with emulate.
simulation. (1) The representation of selected
characteristics of the behavior of one physical or
abstract system by another system, in a digital
computer system, simulation Is done by software; for
example, (a) the representation of physical phenomena
by means of operations performed by a computer
system, and (b) the representation of operations of a
computer system by those of another computer system.
(2) Contrast with emulation.
SNA character string (SOS). Acharacter string
composed of EBCDICcontrols, optionally Intermixed
with end-user data, that Is carried within a
request/response unit.
station. (1) An Input or output point of a system that
uses telecommunication facilities; for example, one or
more systems, computers, terminals, devices, and
associated programs at a particular location that can
send or receive data over a telecommunication line.
(2) A location In a device at which an operation Is
performed, for example, a read station. (3) In SNA, a
link station.
stop bit. Synonym for stop signal.
Glossary X-7