IBM 3270 User Manual page 50

controller. A unit that controls input/output operations
for one or more devices.
control unit. A general term for any device that
provides common functions for other devices or
mechanisms. Synonym for controller.
control unit terminal (CUT). A terminal that relies on
the 3174 to Interpret the data stream. Examples are the
3178, 3179, 3278 Model 2. and 3279 Model S2A.
control unit terminal (CUT) mode. A host-Interactive
mode that enables an IBM 3270 Personal Computer
customized in this mode to run only one session
emulating a 3178, 3179, 3278 Model 2, or 3279 Model
S2A.
conversion. (1) In programming languages, the
transformation between values that represent the same
data Item but belong to different data types.
Information may be lost as a result of conversion
because accuracy of data representation varies among
different data types. (2) The process of changing from
one method of data processing to another or from one
data processing system to another. (3) The process of
changing from one form of representation to another,
for example, to change from decimal representation to
binary representation.
create. In 3174 central site customizing, to create a
library member for a network controller, and store the
customizing data for that library member on a Library
diskette.
cursor. (1) A movable, visible mark used to Indicate
the position at which the next operation will occur on a
display surface. (2) A unique symbol that Identifies a
character position In a screen display, usually the
character position at which the next character to be
entered from the keyboard will be displayed.
data stream. (1) All data transmitted through a data
channel in a single read or write operation. (2) A
continuous stream of data elements being transmitted,
or Intended for transmission. In character or
binary-digit form, using a defined format. See also data
stream format.
data stream format, in SNA, the format of the data
elements (end-user data) In the request unit (RU). See
also 3270 data stream and SNA character string (SCS).
decrypt. To convert encrypted data Into clear data.
Contrast with encrypt.
device. A mechanical, electrical, or electronic
contrivance with a specific purpose.
disk. A direct-access data storage medium, which may
be either flexible (diskette) or hard (fixed disk).
diskette. A flexible magnetic disk enclosed In a
protective container.
diskette drive. The mechanism used to seek, read,
and write data on diskettes.
Disk Operating System (DOS). A program that controls
the operation of an IBM Personal Computer and the
execution of application programs.
display field. (1) An area in the display buffer that
contains a set of characters that can be manipulated or
operated upon as a unit. (2) A group of consecutive
characters (In the buffer) that starts with an attribute
character (defining the characteristics of the field) and
contains one or more alphanumeric characters. The
field continues to, but does not Include, the next
attribute character.
display frame. (1) In computer graphics, an area In
storage In which a display Image can be recorded.
(2) In computer micrographics, an area on a microform
in which a display Image can be recorded.
display station. An Input/output device containing a
display screen and an attached keyboard that allows a
user to send Information to or receive Information from
the system.
EiA communication adapter. A communication adapter
conforming to EIA standards that can combine and
send Information on two lines at speeds up to 19.2
kbps.
emulate. (1) To Imitate one system with another,
primarily by hardware, so that the Imitating system
accepts the same data, executes the same computer
programs, and achieves the same results as the
Imitated computer system.
emulation. (1) The Imitation of all or part of one
system by another, primarily by hardware, so that the
Imitating system accepts the same data, executes the
same programs, and achieves the same results as the
Imitated computer system. (2) The use of
programming techniques and special machine features
to permit a computing system to execute programs
written for another system. (3) Imitation; for example,
imitation of a computer or device. (4) See terminal
emulation. (5) Contrast with simulation.
encrypt. To scramble data or convert It, before
transmission, to a secret code that masks the meaning
of the data to any unauthorized recipient. Contrast with
decrypt.
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