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S
Semiconductor - A material such as silicon or germanium in which the electrical conductivity lies between that of conductors and insulators. It also has a crystal structure whose atomic bonds allow the conduction of current by either positive or negative carriers when the appropriate dopants are added, in which the degree of electrical conductivity of the material is especially sensitive.
Silicon (Si) - A very common element. In the form of Dioxide (or Silica) it is widely used as a semiconductor material.
SIL/SIP - Single In Line/Single In Line Package. Refers to the alignment of connection pins from the plastic ceramic casing surrounding a chip or integrated circuit in its packaged form.
Sine Wave - The wave form adopted by alternating current, following a known oscillation and amplitude, plotted against time. A sinusoidal curve.
Sink - Short for heat sink; a device to absorb unwanted thermal energy.
SIO - Serial Input Output interface. A device for accepting serial input and converting to parallel output.
Small-Scale Integration (SSI) - A term applied to integrated circuits containing from one to twenty logic gates.
Source Code - The original programming statements as they exist in the language that the programmer has used to write the program.
Stable - A condition where no unwanted variations of signal exist.
Statements - Lines of code in a computer program.
Static Memory - Static RAM holds the contents of memory as long as power is being input.
Stepper Motor - An electric motor in which speed can be regulated by a built-in gearbox.
Stop Bit - In data transmission, the bit that is used to describe end of character so that the receiving system then inserts an intercharacter space.
String - A stream of sequentially organized data.
Superconductivity - The theoretical condition that exists when a conductor is cooled to zero degrees absolute. At this temperature electrical resistance should not exist. Thus the lower the temperature in a circuit the better conductor it becomes.
Synchronous (sync., in sync) - Activities that take place in perfectly coordinated timing, often under control of a clock or timer.
Syntax - The grammar or rules of a particular computer language.
Systems Analysis - The process of analyzing the best solution to a problem, either in terms of problem analysis or systems design prior to programming.
T
Transaction - One coherent grouping of data which can update a file or a record.
Transformer - A device which accepts voltage and current at one value and outputs at a different values, but at the same frequency.
Transient - A random and infrequent surge, very brief, caused as the result or a sudden change in conditions.
Transistor - An active semiconductor device with three electrodes (emitter, base and collector). Used as a switch or as an amplifier.
Transmission - Sending signals or data along a known path or circuit.
Twisted Pair - A two wire cable.
U
UART - Universal Asynchronous Receive/Transmit. A standard technique for receiving parallel format data and transmitting serially.
Ultrasonic - Signal frequencies which lie outside the range of human audibility. They start at a 20 kHz frequency.
Unipolar - A transistor fabricated from a single type of semiconductor.
Up Time - The time during which a machine is operational and available for use.
Update - The process of seeking out and amending a record, field, file or document.
Useful Life - The duration of a component's or device's operational life before replacement or repair. Measured in hours of use.
User - A person, grouping or company which makes regular use of, or has access to computer systems.
V
V - Volts
Validate - The process of auditing output or results from a circuit or system to ascertain whether they are reasonable and fall within the bounds of probability.
Variable - Any data obtained from measurement which can be altered.
Virtual Memory - A technique offered by many manufacturers which make the memory size look larger to the program than it actually is. The virtual memory operating system scans programs for code that has already been used or has low priority. It then moves these parts of the programs into a temporary storage area, unknown to the user or programmer. It does not generally affect the speed or execution it the total size of programs to be executed does not exceed available memory by more than 25% or so. Thereafter there is an increasing degradation in performance.
Volatile Memory - A type of RAM which requires a constant refresh of contents.
Voltage (V) - A measure of the potential difference, emf (electromotive force), or voltage in a circuit.
W
W - Watts
WAIT - A software or operating system command which causes the computer to suspend processing until a certain condition is met.
Warm Start - A system restart after a fairly brief pause.
Watts (W) - A measure of power developed by the flow of current through a circuit. One watt is the product of one amp and one volt.
Waveform - The shape of a pulse, usually associated with alternating current.
Word Processing - The use of computer techniques to manipulate text rather than data.
Wraparound - An automatic overflow on the next available line of contiguous data or text.
X
X.25 - A data communications interface specification that describes how data pass into and out of packet switching networks.
X.400 - Protocol for electronic mail and public data networks. X.400 wraps messages in an electronic envelope, which will then be accepted by any system that can read the envelope.
X.500 - Standard for listing names in an electronic directory (e.g. electronic white pages). This standard enables the directory to be accessed internationally and by a variety of electronic networks.
X Axis - The horizontal line, real or imaginary, which forms the axis for a wave shape measurement against the vertical Y axis. Also used for alignment on graph plotters and monitors
XMODEM - A data transmission file transfer protocol with 8-bit error checking. The protocol sends information in 128-byte blocks. Popular among business users of microcomputers.
X Ray - Electromagnetic radiation of a high frequency.
X-Series - Standards of the CCITT for communications interfaces, such as modems.
X-Y Plotter - A graphical output device in which results are recorded by moving the writing pen across the paper in the direction of the X and Y coordinates.
Y
Y Axis - The vertical axis of a waveform.
Yellow Pages - A directory of user names, passwords, and machine names on a local network. It provides automatic machine addressing and facilitates managing databases distributed across a network.
YMODEM - A data transmission file transfer protocol. The protocol sends information in 1024-byte blocks of data. A faster method of data transmission than XMODEM.
Z
Z39.50 Protocol - A National Information Standards Organization (NISO) protocol that provides a common command language used for bibliographic information retrieval of online library catalogs.
Z - Impedance
Zero Access Store - A very fast type of memory, or area of storage, which can provide the processor with data at speeds as fast as the central processor is able to process that data.
Zero Potential - Earth (ground)
Zip - A method of compressing files for storage or transfer.
ZMODEM - A data transmission file transfer protocol. Generally regarded as the fastest and most efficient way to transfer data
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