Switched Ethernet A newer variant of Ethernet that provides
better performance than shared Ethernet at a higher price.
A switch is substituted for the shared Ethernet’s hub, and the
LAN operates as a logical star as well as a physical star. The
switch is smarter than a hub—rather than passing all communica-
tions through to all devices on the LAN, which is what a hub
does, the switch establishes separate point-to-point circuits to
each device and then forwards communications only to the
appropriate device. See alsoEthernet, Shared Ethernet.
SWOT analysis A situation analysis conducted as part of
strategic planning or when comparing opportunities for IT invest-
ment. SWOT refers to strengths, weaknesses, opportunities, and
threats.
Symmetric multiprocessor (SMP) A multiprocessor
computer configuration in which all the processors (CPUs) are
identical, with each processor acting independently of the others.
The multiple CPUs equally share functional and timing access to
and control over all other system components, including memory
and the various peripheral devices, with each CPU working in its
own allotted portion of memory.
Synchronous Optical Network (SONET) American National
Standards Institute (ANSI)–approved standard for connecting
fiber-optic transmission systems; this standard is employed in a
range of high-capacity lines varying from the OC-1 level of
nearly 52 mbps to the OC-3072 level of 159 gbps.
System A set of interrelated components that must work
together to achieve some common purpose.
System decoupling Reducing the need to coordinate two
system components. Decoupling is accomplished by creating
slack and flexible resources, buffers, sharing resources, and
standards.
System development methodology A framework of guide-
lines, tools, and techniques for developing computer systems. See
alsoSystems development life cycle, Prototyping.
System requirements A set of logical and physical capabilities
and characteristics that a new (or modified) system is required to
have upon its implementation (or installation).
Systems analysis and design (SA&D) Major activities per-
formed by IS specialists that are part of systems development and
implementation methodologies. See alsoSystems development
life cycle, Prototyping, Rapid application development.
Systems analyst IS specialist who works with users to develop
systems requirements and help plan implementations and who
works with systems designers, programmers, and other infor-
mation technology (IT) specialists to construct systems based on
the user requirements.
Systems development life cycle (SDLC) The traditional
methodology used by IS professionals to develop a new computer
application that includes three general phases: Definition,
Construction, and Implementation. Also referred to as a “water-
fall” process because of its sequential steps. The SDLC method-
ology defines the activities necessary for these three phases, as
well as a framework for planning and managing a development
project. Operations and maintenance are included in the
Glossary 687Implementation phase. A modified SDLC approach is used to
purchase packaged systems.
Systems Network Architecture (SNA) A set of network pro-
tocols created by IBM to allow its customers to construct their
own private networks using the wide variety of IBM communica-
tion products, teleprocessing access methods, and data link proto-
cols. SNA was first created in 1974 and is still in widespread use.
Systems software SeeSupport software.
T-1 lines The most common leased communication lines,
operating at a data transmission rate of 1.544 million bits per
second. These lines, which may be leased from AT&T or another
long-distance carrier, often provide the basis for a wide area
network (WAN).
Tablet PC A variation of a notebook computer (PC) where
the user writes on an electronic tablet (usually the video screen
folded flat on top of the PC) with a digital pen. Please note that a
tablet PC can also be used as a standard notebook computer.
TCO SeeTotal cost of ownership.
TCP/IP SeeTransmission Control Protocol/Internet Protocol.
Telecommunications Communications at a distance, including
voice (telephone) and data (text/image) communications. Other
similar terms used almost interchangeably with tele-
communications include data communications, datacom, tele-
processing, telecom, and networking.
Telecommuter A person who works at home or at another
location that is not part of a regular office environment and who
uses computers and communications to connect to organizational
resources to accomplish his or her work; includes mobile work-
ers, other “road warriors,” and free agents. See alsoFree agent.
Terminal A computer-related device that has input (keyboard,
mouse) and output (video display) capabilities, but does essen-
tially no processing, and thus operates as a “slave” to a “master”
computer, usually a midrange system or a mainframe. For some
applications, a microcomputer may emulate a terminal so that it
can operate with a large computer system.
Third generation language A programming language in
which the programmer expresses a step-by-step procedure
devised to accomplish the desired task. Examples include
FORTRAN, COBOL, BASIC, and C.
Third-party implementation partner Outside consultants
who are contracted to manage a packaged software
implementation project at a client’s site as employees of an
independent consulting firm, not employees of the vendor of the
software package. For example, the large enterprise system
vendors typically certify large consulting firms (such as the
“Big 4”), IT industry consultants (such as IBM), and smaller con-
sulting firms on different versions of their software packages, and
these third-party businesses provide employees who work on
project teams at the client site, while the vendors’ employees
only provide on-site technical support as needed.
Three-tier client/server system A variation of a client/server
system in which the processing is split across three tiers, the
client and two servers. In the most popular three-tier system, the