BSEH Secondary Computer Science flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Binary number system

Base-2 number system using only digits 0 and 1; each position represents a power of 2, used internally by digital computers.

Hexadecimal

Base-16 number system using digits 0–9 and letters A–F; each hex digit corresponds to four binary bits, often used to shorten binary notation.

Two's complement

Method for representing signed integers in binary: invert all bits of the positive value and add 1 to obtain the negative value.

CPU

Central Processing Unit; executes program instructions by fetching, decoding, and executing them, and contains the ALU, control unit, and registers.

RAM

Random Access Memory; volatile primary storage that holds currently running programs and data and loses its contents when power is off.

Cache memory

Small, very fast memory between CPU and RAM that stores frequently accessed data to reduce average memory access time.

Operating system

System software that manages hardware, processes, memory, files, and devices, and provides a user interface for running applications.

Utility software

Program that helps maintain a computer system, such as antivirus, backup, disk cleanup, and file compression tools.

GUI

Graphical User Interface; allows users to interact with a computer using windows, icons, menus, and a pointer instead of typed commands.

Algorithm

Finite, unambiguous sequence of steps that solves a problem or performs a computation and must terminate.

Flowchart decision symbol

Diamond-shaped symbol in a flowchart representing a condition with two or more outgoing branches, such as yes/no paths.

Syntax error

Programming mistake that violates the grammar rules of a language, preventing the program from compiling or running.

Python indentation

Spaces at the start of a line that define code blocks in Python; inconsistent indentation causes errors or changes program logic.

range() function

Python function that generates a sequence of integers from start up to but excluding stop, with an optional step value.

C++ semicolon

Character that terminates a statement in C++; omitting it causes a compile error.

Mean

Measure of central tendency calculated by dividing the sum of all data values by the number of values.

Primary key

Field or combination of fields that uniquely identifies each record in a database table and cannot contain duplicate values.

Spreadsheet absolute reference

Cell reference with dollar signs before column and row (e.g., $B$3) that stays fixed when copied to another cell.

File append mode

File open mode that adds new data to the end of an existing file without erasing its current contents.

SQL SELECT

Statement that retrieves data from one or more database tables, optionally filtered with a WHERE clause and ordered with ORDER BY.

CSV file

Plain-text file format storing tabular data as comma-separated values, with each line representing a record.

IP address

Numeric label assigned to a device on a network so data packets can be routed to it; IPv4 is 32-bit and IPv6 is 128-bit.

DNS

Domain Name System; translates human-readable domain names into IP addresses so browsers can locate web servers.

LAN

Local Area Network; connects devices within a small geographic area such as a room, school, or office building.

Phishing

Cyberattack using fraudulent messages that impersonate trusted sources to trick users into revealing passwords or personal information.

Two-factor authentication

Security method requiring two independent forms of verification, such as a password plus a one-time code, before granting access.

Digital footprint

Trail of data left by a person's online activity, including posts, searches, and messages, which may persist indefinitely.

Cloud computing

Delivery of computing services such as storage, processing, and software over the Internet on demand, often billed by usage.

Internet of Things

Network of everyday physical devices embedded with sensors and software that collect and exchange data over the Internet.

Augmented reality

Technology that overlays digital information such as images or text onto a user's view of the real world.

Test data

Set of inputs chosen to verify a program, including normal, boundary, and invalid cases to reveal errors.

Dry run

Manual step-by-step execution of an algorithm or program using sample data to check logic and expected output.