instructions (operations to be performed) from memory one at
a time, interprets each instruction, and carries it out—all at elec-
tronic speed. See alsoCentral processing unit, Stored-program
concept.
Controller A hardware unit to link input/output or file devices
to the CPU and memory of large computer systems. The
controller is a highly specialized microprocessor that manages
the operation of its attached devices to free the CPU from these
tasks.
Cookie As used with the Web, a cookie is a message given to a
Web browser by a Web server. The browser stores the message on
the user’s hard drive, and then sends it back to the server each
time the browser requests a page from the server. The main
purpose of cookies is to identify users and possibly prepare
customized Web pages for them.
Cordless telephone A portable telephone instrument that can
be used up to about 1,000 feet from its wired telephone base unit;
this permits the user to carry the instrument to various rooms in a
house or take it outdoors.
Corporate data model A chart that describes all the data
requirements of a given organization. This chart shows what data
entities and relationships between the entities are important for
the organization.
Corporate information policy The foundation for managing the
ownership of data; a policy describing the use and handling of data
and information within the corporation.
Cost-benefit analysis A process to identify the potential costs
and benefits of a new initiative as part of an organization’s
decision making about whether or not to proceed with the initia-
tive. For example, a rough cost-benefit analysis is typically
conducted prior to the approval of a new application software
project, and a more detailed analysis is conducted after the proj-
ect requirements are better defined to ensure that the organiza-
tional benefits outweigh the project costs.
Coverage model A common data model used in geographic
information systems in which different layers or themes represent
similar types of geographic features in the same area (e.g., coun-
ties, highways, customers) and are stacked on top of one another.
CPU SeeCentral processing unit.
Cracker A person who breaks into a computer system to steal
information, wipe out hard drives, or do other harm. See also
Hacker.
Credit bureau A company that collects information from
various sources and provides consumer credit information on
individual consumers for a variety of uses, including buying a
home or car, taking out an insurance policy, and renting an apart-
ment or home. The three large credit bureaus in the United States
are Experian, Equifax, and TransUnion LLC.
Critical success factors (CSFs) A limited number of organiza-
tional activities that, if done well, will contribute the most to the
successful performance of an organization or function.
CRM SeeCustomer relationship management system.
CSFs SeeCritical success factors.
CSMA/CA Protocol An abbreviation for Carrier Sense
Multiple Access with Collision Avoidance, the protocol used in a
wireless design for a local area network. CSMA/CA is quite sim-
ilar to CSMA/CD used in traditional Ethernet, but it makes
greater efforts to avoid collisions. See alsoCSMA/CD Protocol.
CSMA/CD Protocol An abbreviation for Carrier Sense
Multiple Access with Collision Detection, the protocol used in the
contention bus design for a local area network. With this protocol,
any device may transmit a message if the bus is idle. However, if
two devices start to transmit at the same time, a collision will
occur and the messages will become garbled. Both devices must
recognize that this collision has occurred, stop transmitting, wait
some random period of time, and then try again.
CTO SeeChief technology officer.
Customer relationship management (CRM) system A computer
application that attempts to provide an integrated approach to all
aspects of interaction a company has with its customers, including
marketing, sales, and support. A CRM system often pulls much of its
data from the organization’s data warehouse; most CRM packages
depend upon capturing, updating, and utilizing extensive profiles of
individual customers.
DASD SeeDirect access storage device.
Data administration The name typically given to an organiza-
tional unit created to lead the efforts in data management; the
group often reports as a staff unit to the IS director, although
other structures are possible.
Data analysis and presentation application An application
that manipulates data and then distributes information to
authorized users. These applications concentrate on creating use-
ful information from established data sources and, because they
are separate from data capture and transfer systems, can be indi-
vidually changed without the expense of changing the data
capture and transfer systems.
Data architecture SeeData model.
Data capture application An application that gathers data and
populates databases. These applications allow the simplification
of all other applications that then transfer or report data and
information.
Data center A computer installation that stores, maintains, and
provides access to vast quantities of data; includes computer
hardware (servers, midrange systems, mainframes, and/or super-
computers), communications facilities, system software, and
technical support and operations staff.
Data dictionary/directory (DD/D) Support software that
provides a repository of metadata for each data element in a
system—including the meaning, alternative names, storage format,
integrity rules, security clearances, and physical location of data—
that is used by the DBMS and system users.
Data flow diagram (DFD) A common diagrammatic technique
for logical As-Is and To-Be models. Symbols are used to represent
the movement, processing, and storage of data in a system and both
inputs from and outputs to the environment. Each process in a
top-level DFD is decomposed to a lower level, and so on.672 Glossary