IB Computer Science HL
Terms 2026 | Key Terms,
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Ethics Study Guide
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,abstract data structure A way of organizing data and its related procedures and functions.
accessor methods Methods that do not alter the state or attributes of an object; their purpose is to
return information.
accumulator A storage register in the ALU that holds data temporarily while the data is processed
and before it is transferred to memory.
A-D converter Analog-digital converter. A device for converting analog signals into digital ones for
subsequent computer processing; sometimes called a "digitizer". A digital to analog
(D to A) converter operates in the reverse direction.
ADSL (Asymmetrical Digital Subscriber Line) Technology that increases the data rate over existing telephone lines
accommodating voice and digital data transfer. A special modem is needed for
access.
address bus Pathway from memory to processing unit that carries the address in memory to and
from which data is transferred. See the definitions for "bus" and "data bus".
algorithm An ordered set of well-defined instructions for the solution of a problem in a finite
number of steps.
ALU See the definition for "arithmetic and logic unit".
analog data The representation and measurement of the performance or behaviour of a system
by continuously variable physical entities such as currents, voltages and so on. See
also the definition for "digital data".
and The output of "and" is True if all statements are True, False if any statement is
False.
applet (Java) A program that runs in the context of a browser.
application (Java) A program that runs when translated by a Java compiler.
, archive Data that represents a record of data held and processed at a specific time, which is
held off-line for future research or for legal reasons.
argument A value or object passed to a method when it is called.
arithmetic and logic unit (ALU) A part of the computer that performs arithmetic operations, logic operations and
related operations.
array 1. An arrangement of data in one or more dimensions.
2. In programming languages, an aggregate that consists of data objects, with
identical attributes, each of which may be uniquely referenced by indexing.
ASCII: American Standard Code for Information The primary encoding character set used in computers for textual data transfer
Interchange between applications. The set uses eight bits for each character code, one of these
bits being a check bit to verify the seven bits needed to represent one character.
ASCII supports most European alphabets. Unicode supports most known alphabets
and is increasingly used in data transfer. See also the definition for "Unicode".
attribute Element of data contained in an object; as specified within the object's class.
B Byte.
back-up (file) A second copy of a file, to be used in the event of the original file being corrupted.
balanced tree A tree in which the right and left subtrees of any node have heights differing by one
at the most. See also the definition for "unbalanced tree".
bar code A pattern of vertical lines distinguished from each other by width. It can be read by a
bar code reader to provide data to a computer.
bar code reader An optical reader that can read bar codes.
base The basis of a notation or number system, defining a number representational
system by positional representation. In a decimal system the base is 10, in a
hexadecimal system the base is 16, and in a binary system the base is 2.
Terms 2026 | Key Terms,
Study Guide, Practice
Questions, Answers &
Exam Review | Complete
Ethics Study Guide
Updated 2026 Questions and Answers
100% Verified Exam Prep and Comprehensive
Rationales
Included
,abstract data structure A way of organizing data and its related procedures and functions.
accessor methods Methods that do not alter the state or attributes of an object; their purpose is to
return information.
accumulator A storage register in the ALU that holds data temporarily while the data is processed
and before it is transferred to memory.
A-D converter Analog-digital converter. A device for converting analog signals into digital ones for
subsequent computer processing; sometimes called a "digitizer". A digital to analog
(D to A) converter operates in the reverse direction.
ADSL (Asymmetrical Digital Subscriber Line) Technology that increases the data rate over existing telephone lines
accommodating voice and digital data transfer. A special modem is needed for
access.
address bus Pathway from memory to processing unit that carries the address in memory to and
from which data is transferred. See the definitions for "bus" and "data bus".
algorithm An ordered set of well-defined instructions for the solution of a problem in a finite
number of steps.
ALU See the definition for "arithmetic and logic unit".
analog data The representation and measurement of the performance or behaviour of a system
by continuously variable physical entities such as currents, voltages and so on. See
also the definition for "digital data".
and The output of "and" is True if all statements are True, False if any statement is
False.
applet (Java) A program that runs in the context of a browser.
application (Java) A program that runs when translated by a Java compiler.
, archive Data that represents a record of data held and processed at a specific time, which is
held off-line for future research or for legal reasons.
argument A value or object passed to a method when it is called.
arithmetic and logic unit (ALU) A part of the computer that performs arithmetic operations, logic operations and
related operations.
array 1. An arrangement of data in one or more dimensions.
2. In programming languages, an aggregate that consists of data objects, with
identical attributes, each of which may be uniquely referenced by indexing.
ASCII: American Standard Code for Information The primary encoding character set used in computers for textual data transfer
Interchange between applications. The set uses eight bits for each character code, one of these
bits being a check bit to verify the seven bits needed to represent one character.
ASCII supports most European alphabets. Unicode supports most known alphabets
and is increasingly used in data transfer. See also the definition for "Unicode".
attribute Element of data contained in an object; as specified within the object's class.
B Byte.
back-up (file) A second copy of a file, to be used in the event of the original file being corrupted.
balanced tree A tree in which the right and left subtrees of any node have heights differing by one
at the most. See also the definition for "unbalanced tree".
bar code A pattern of vertical lines distinguished from each other by width. It can be read by a
bar code reader to provide data to a computer.
bar code reader An optical reader that can read bar codes.
base The basis of a notation or number system, defining a number representational
system by positional representation. In a decimal system the base is 10, in a
hexadecimal system the base is 16, and in a binary system the base is 2.
