IBM 3270 User Manual page 49

I Glossary
active. Able to communicate on the network. An
adapter is active If It Is able to pass tokens on the
network.
adapter. A general term for a device that provides
some transitional function between two or more
devices.
address. (1) A value that identifies a register, a
particular part of storage, a data source, or a data sink.
The value Is represented by one or more characters.
(2) To refer to a device or an Item of data by Its
address. (3) In word processing, the location.
Identified by an address code, of a specific section of
the recording medium or storage. (4) The location In
the storage of a computer where data is stored. (5) In
data communication, the unique code assigned to each
device or work station connected to a network.
alternate cursor. (1) An Image reversal of each dot In
the character cell at the cursor position. (2) A cursor
other than the one displayed on the display surface at
power on time.
application. The use to which an information
processing system Is put, for example, a payroll
application, an airline reservation application, or a
network application.
asynchronous. (1) Without regular time relationship;
unexpected or unpredictable with respect to the
execution of program Instructions. (2) In asynchronous
data transmissions, data characters may be sent or
received at any time; no modem clocking Is used to
establish bit timing.
Asynchronous Emulation Adapter (AEA). In the 3174
Establishment Controller, an adapter that enables an
ASCII terminal to communicate with a 3270 host using
the 3270 data stream, an ASCII terminal to
communicate with an ASCII host through the 3174, and
a 3270 terminal to communicate with an ASCII host
using data streams, such as the DEC VT100 data
stream or the IBM 3101 data stream.
attachment feature. The circuitry by which a cable
from a local terminal or a modem for a remote terminal
Is attached to a 3792 Auxiliary Control Unit or a 3791
Controller.
attribute. (1) A characteristic. (2) A terminal display
language or transformation definition language (TDL)
keyword that specifies a particular quality for the TDL
object with which It Is associated.
audible alarm. (1) An alarm that Is sounded when
designated events occur that require operator attention
or Intervention before system operation can continue.
(2) A special feature that sounds a short, audible tone
automatically when a character Is entered from the
keyboard Into the next-to-last character position on the
screen. The tone can also be sounded under program
control.
central site customizing. The process of tailoring
control unit microcode for each controller In a network,
at the central site.
channel-attached. Pertaining to attachment of devices
directly by data channels (I/O channels) to a computer.
Synonym for local. Contrast with
telecommunication-attached.
channel-to-channel adapter. A hardware device that
can be used to connect two channels on the same
computing system or on different systems.
character set. (1) A defined collection of characters.
(2) A group of characters used for a specific reason,
for example, the set of characters a printer can print.
(3) The collection of graphic characters required to
support a specific language.
command. An Instruction that directs a control unit or
device to perform an operation or a set of operations.
communication adapter. (1) A circuit card with
associated software that enables a processor,
controller, or other device to be connected to a
network. (2) See EIA communication adapter, V.35
communication adapter, and X.21 communication
adapter.
Concurrent Communication Adapter (CCA). In the 3174
Establishment Controller, a communication adapter
that, along with the necessary microcode, provides
terminals attached to the 3174 the ability to
concurrently access an additional 3270 host.
configuration. The arrangement of a computer system
or network as defined by the nature, number, and chief
characteristics of Its functional units. More specifically,
the term configuration may refer to a hardware
configuration or a software configuration. See also
system configuration.
control character. (1) A character whose occurrence
In a particular context specifies a control function.
(2) A character used to specify that a control unit Is to
perform a particular operation.
' Copyright IBM Corp. 1983,1990
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