Appendix A
Glossary
absolute value Value of a quantity expressed as a positive number, e.g., |f(x)|.
accuracy The degree of exactness provided by a description or a theory. Accuracy usually refers to an absolute quality, while precision usually refers to the number of digits used to represent a number.
address The numerical designation of a location in memory. An identifier, such as a label, that points to an address in memory or a data source.
algorithm A set of rules for solving a problem in a finite number of steps. Usually independent of the software or hardware.
allocate To assign a resource for use, often memory.
alphanumeric The combination of alphabetic letters, numerical digits, and special characters, such as %, $, and /.
analog The mapping of a continuous physical observable to numbers. As an instance, a car’s speed to its speedometer.
animation A process in which motion is simulated by presenting a series of slightly different pictures (frames) in succession.
append To add on, especially to the end of an object or word.
application A self-contained executable program containing tasks to be performed by a computer, usually for a practical purpose.
architecture The overall design of a computer in terms of its major components: memory, processor, I/O, and communication.
archive To copy programs and data to an auxiliary medium or file system for long-term and compact storage.
argument A parameter passed from one program part to another, or to a command.
arithmetic unit Part of the central processing unit that performs arithmetic.
array (matrix) A group of numbers stored together in rows and columns that may be referenced by one or more subscripts. Each number in an array is an array element.
assignment statement Command that sets a value to a variable or symbol.
B Abbreviation for byte (8 bits).
b Abbreviation for bit or baud (1 bit/sec).
background (1) A technique of having a programming run at low priority (“in background”) while a higher-priority program runs “in foreground.” (2) The part of video display not containing windows.
base The radix of a number system. (10 is the radix of the decimal system.)
basic machine language Instructions telling the hardware to do basic operations such as store or add binary numbers.
batch The running of programs without user interaction; often in background.
baud 1 bit per second.
binary Related to the number system with base 2.
BIOS Basic Input/Output System.
bit Contraction of “binary digit”; the digits 0 or 1 used in binary representation.
Boolean algebra A branch of symbolic logic dealing with logical relations as opposed to numerical values.
boot To “bootstrap”; to start a computer by loading the operating system.
branch To pick a path within a program based on the value of variables.
bug A mistake in a computer program or operating system; a malfunction.
bus A communication channel (bunch of wires) used for transmitting information quickly among computer parts.
byte Eight bits of storage. Java uses two bytes to store a single character in extended unicode.
byte code Compiled code that is read by all computer systems, but still needs to be interpreted (or recompiled) on each system. Contained in class file.
cache Small, very fast part of memory used as temporary storage between the very fast CPU registers and main memory.
calling sequence The data and setup needed to call a method or a subprogram.
central processing unit (CPU) The part of a computer that accepts and acts on instructions; where calculations are done and communications controlled.
checkpoint A statement within a program that stops normal execution and provides some output to assist in debugging.
checksum The summation of digits or bits used to check the integrity of data.
child Object created by presently existing parent object.
class A group of objects or methods having a common characteristic. Collection of data types and associated methods. An instance of an object. Byte code version of a Java program.
clock Electronics that generate the periodic signal to begin execution.
code A program or the writing of a program.
column The vertical line of numbers in an array.
column-major order The method used by Fortran to store matrices in which the leftmost subscript varies most rapidly and attains its maximum value before the subscript to the right is incremented. (Java uses row-major order.)
command A computer instruction. A control signal.
command key A keyboard key, or combination of keys, that performs a predefined function.
compilation Translation of a program written in a high-level language into (more) basic machine language.
compiler A program that translates source code from a high-level computer language to machine language or object code.
concatenate To join together two or more strings, head to tail.
concurrent processing Same as parallel processing; simultaneous execution of several related instructions.
conditional statement Statement to be executed only under certain conditions.
control character A character that modifies or controls the running of a program (e.g., control +c).
control statement A statement within a program that transfers control to another section of the program.
copy To transfer data without removing the original.
CPU See central processing unit.
crash The abnormal termination of a program or a piece of hardware due to some malfunction.
cycle time (clock speed) Time it takes CPU to execute simplest instruction.
data Information stored in numerical form; plural of datum.
data type Definitions that permits proper interpretation of character string.
debug To detect, locate, and remove mistakes in a program or hardware.
default The assumption made when no specific directive is given.
delete To remove and leave no record.
digital Representation of quantities in discrete form; contrast analog.
dimension of array Number of subscripts needed to access single array element.
directory A collection of files given their own name.
disc, disk A circular magnetic medium used for storage.
discrete Related to distinct elements.
double precision Use of two memory words to store a number.
download To transfer data from a remote computer to a local computer.
driver A set of instructions needed to transmit data to/from external device.
dump Data resulting from listing all information in memory.
dynamic RAM Computer memory that must be refreshed at frequent intervals.
E A symbol for exponent. To illustrate, 1.97E2 = 1.97 × 102.
element An item of data within an array; a component of a language.
enable To make a computer part operative.
ethernet A high-speed local area network (LAN) composed of specific cable technology and communication protocols.
executable program A set of instructions that can be loaded into the computer’s memory and executed.
executable statement A statement that causes some computational action, such as assigning a value to a variable.
fetch To locate and retrieve information from storage.
floating point Representation of numbers as mantissa times base raised to a power. Scientific notation.
FLOP Floating Point Operation.
foreground Running high-priority programs before low.
Fortran An acronym for formula translation.
fragmentation File storage in many small, dispersed pieces.
G Abbreviation for giga; one billion in USA; 109.
garbage Meaningless numbers, usually the result of error or improper definition. Obsolete data in memory waiting to be removed (“collected”).
giga Prefix indicating one billion, 109, of something (USA).
GUI Graphical user interface; a window environment.
hard disk A circular, spinning, storage device using magnetic memory.
hardware Physical components of a computer system.
hashing A transformation that converts keystrokes to data values.
heuristic A trial-and-error approach to problem solving.
hexadecimal Base 16; {0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F}.
hidden line surface Part of a graphics object normally hidden from view.
high-level language Programming language similar to normal language.
host computer A central computer providing services to terminals.
icon Small on-screen symbol that activates an application.
increment The amount added to a variable, especially an array index.
index The symbol used to locate a variable in an array, the subscript. A reference table kept in memory.
infinite loop The endless repeating of a set of instructions.
input Introduction of data from an external device into main storage.
instructions Orders to the hardware to do basic things such as fetch and add.
instruction stack Group of instructions currently in use.
interpolation Finding values between known values.
interpreter A language translator that converts each line of source code into machine code and immediately executes each line.
interrupt A command that stops execution of a program when some abnormal condition is encountered.
iterate To repeat a series of steps automatically.
jump A departure from the linear processing of code; branch, transfer.
just-in-time compiler A procedure that takes a Java class file that would ordinarily be interpreted and recompiles it into a more efficient machine code.
K Abbreviation for KILO, one thousand, 103.
kernel The central part of a large program or operating system that does not get significantly modified when run on different computers.
kill To delete or stop a process.
language Rules, representations, and conventions used to convey information.
library (lib) A collection of programs or methods usually on a related topic.
linking The connecting of separate pieces of code to form an executable program.
literal A symbol that defines itself, such as the letter A.
load To read information into the computer’s memory.
load module A program that is loaded into memory and run immediately.
log in (on) To sign onto the computer, to begin a session.
loop A set of instructions executed repeatedly as long as some condition is met.
low-level language Machine-related programming not easy for humans to read.
machine language The set of instructions understood by the computer hardware.
machine precision The maximum positive number that, when added to the number stored as 1, does not change it.
macro A single, higher-level statement resulting in several lower-level ones.
main method Part of application program where execution begins; may call other methods but cannot be called by them.
main storage The fast, electronic memory; physical memory.
mantissa The significant digits in a floating-point number; e.g., 1.2 in 1.2E3.
mega, M A prefix denoting a million, or 1, 048,576 = 220.
metalanguage A language used to define other languages.
method A subroutine used to calculate a function or manipulate data.
modular programming The technique of writing program with many, reusable, and independent parts.
modulo (mod) Function that yields only remainder after division of numbers.
multiprocessors Computers with more than one processor.
multitasking The system by which several jobs reside in a computer’s memory simultaneously; may run in parallel or sequentially.
nesting Embedding a group of statements within another group.
object A software component with properties like physical objects. A combination of data (variables, properties) and methods (behaviors) to interact with the data; and abstract data type containing multiple parts.
object-oriented programming A modular programming style focused on classes of data objects and associated methods to interact with the objects.
object program (code) A program in basic machine language produced by compiling a high-level language.
octal Base 8; easy to convert to or from binary.
operating system (OS) The program that controls the computer and runs applications, processes I/O, and shells.
optimization The modification of a program to make it run more quickly.
overflow A number that is larger than the largest number a computer can store accurately.
package A collection of related programs or classes.
page A segment of disk memory that gets read into central memory in one block.
parallel (concurrent) processing Simultaneous or independent processing in different CPUs.
parallelization Rewriting an existing program to run on a parallel computer.
partition The section of memory assigned to a program during its execution.
physical memory The fast, electronic memory of a computer; main memory; contrast to virtual memory.
physical record The physical unit of data for input or output that may contain a number of logical records.
pipeline (segmented) arithmetic units Assembly-line approach to central processing in which CPU simultaneously gathers, stores, and processed data.
pixel A picture element, a dot on the screen. See also voxel.
portable document format, pdf A document format developed by Adobe that is of high quality and still readable within a Web browser.
PostScript, ps A standard language developed by Adobe for sending text and graphics to printers.
precision The degree of exactness with which a quantity is presented. High-precision numbers are not necessarily accurate.
program A set of instructions that a computer interprets and executes.
protocol A set of rules or conventions.
pseudocode A mixture of normal language and coding that provides a symbolic guide to a program.
queue An ordered group of items waiting to be acted upon in turn.
radix The base number in a number system that gets raised to powers.
RAM Random access (central) memory that is reached directly.
random access Reading or writing memory independent of storage order.
record A collection of data items treated as a unit.
recurrence (recursion) The use of a loop to produce new values of a variable computed in previous iterations.
registers Very high-speed memory used by the central processing unit.
reserved words Words that cannot be used in an application program.
RISC Reduced Instruction Set Computer; a CPU design that increases arithmetic speed by decreasing the number of instructions the CPU must follow.
row-major order The method used by Java to store matrices in which the rightmost subscript varies most rapidly and attains its maximum value before the subscript to the left is incremented.
run To execute a program.
scalar A data value or number, for example, π.
serial/scalar processing Calculations in which numbers are processed in sequence. Contrast to vector and parallel processing.
shell The command line interpreter; the part of the operating system in which the user enters commands.
simulation The modeling of a real system by a computer program. The use of one system to represent or model another one.
single precision The use of one computer word to store a variable.
software Programs or instructions.
source code Program in high-level language needing compilation to run.
stochastic A process in which there is an element of chance.
string A connected sequence of characters treated as a single object.
structure The organization or arrangement of a program or a computer.
subprogram The part of a program invoked by another program unit, a method.
supercomputer The class of fastest and most computers available.
syntax The rules governing the structure of a language.
telnet Protocols for computer–computer communications.
tera, T 1012, or 230 = 1, 073,741,824.
top-down programming Designing a program from the most general view of the problem, down to the specific subroutines.
unary An operation that uses only one operand; monadic.
underflow A result that is smaller than the smallest number that a computer stores properly.
unit A device having a special function.
upload To transfer data from a local to a remote computer; opposite of download.
utility programs Programs to enhance other programs or do chores.
vector A group of N numbers in memory arranged in one-dimensional order.
vector processing Calculations in which an entire vector of numbers is processed with one operation.
virtual memory Memory on the slow, hard disk and not in fast RAM.
visualization The production of two- and three-dimensional pictures or graphs of the numerical results of computations.
volume A physical unit of a storage medium, such as a disk.
word A unit of main storage, usually 1, 2, 4, 6, or 8 bytes.
word length The amount of memory used to store a computer word.