MATSEC AM Information Technology flashcards

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

Data

Raw, unprocessed facts and figures with no context applied, such as a list of numbers or a set of readings. On its own data has no meaning until it is processed.

Information

Data that has been processed, organised and given context so that it is meaningful and useful for decision-making, for example a summarised sales report.

CPU

The central processing unit executes program instructions. It contains the control unit, which coordinates operations, the ALU for arithmetic and logic, and registers for temporary data.

Control unit

The CPU component that fetches and decodes instructions and directs other units by issuing control signals, coordinating the fetch-decode-execute cycle.

ALU

The arithmetic logic unit performs arithmetic operations such as addition and subtraction and logical comparisons such as AND, OR and NOT within the CPU.

RAM

Random access memory is volatile primary storage holding programs and data currently in use. Its contents are lost when power is removed.

ROM

Read-only memory is non-volatile primary storage whose contents are written at manufacture and normally cannot be altered. It typically holds firmware such as the bootstrap loader.

Cache memory

Small, very fast memory between the CPU and RAM that stores frequently used instructions and data, reducing average access time and speeding up processing.

Solid-state storage

Secondary storage using flash memory with no moving parts. It offers fast access, low power use and shock resistance, but has a higher cost per gigabyte than magnetic disks.

Operating system

System software that manages hardware resources, runs applications and provides a user interface. Its core functions are process, memory, file and device management.

Utility software

System software that maintains and optimises the computer, for example antivirus scanners, disk defragmenters, backup tools and file compression programs.

Compiler

A translator that converts an entire high-level language source program into machine code before execution, producing an executable file and reporting errors after full translation.

Interpreter

A translator that converts and executes a high-level program one statement at a time, reporting errors immediately and stopping at the first fault, but running more slowly.

Assembler

A translator that converts assembly language, a low-level language using mnemonics, into machine code. Assembly is hardware-specific, so programs are not portable.

LAN

A local area network covers a small geographical area such as one building or campus. It is usually privately owned, offers high data rates and uses shared cabling or wireless links.

WAN

A wide area network spans large geographical areas such as countries. It typically uses leased telecommunications links, is more expensive to install and has lower data rates than a LAN.

Star topology

A network layout in which every device connects to a central hub or switch. A single cable failure affects only one device, but failure of the central device disables the network.

IP address

A unique numeric address assigned to a device on a network so data packets can be routed to it. IPv4 uses 32 bits; IPv6 uses 128 bits.

Router

A network device that forwards data packets between different networks, choosing the best path using addressing information, and commonly connects a LAN to the Internet.

Switch

A network device that connects devices within one LAN and forwards frames only to the port of the intended destination, using MAC addresses, reducing unnecessary traffic.

Protocol

An agreed set of rules governing how devices exchange data, covering data format, timing, error handling and addressing. TCP/IP is the basis of the Internet.

Binary number system

A base-2 number system using only the digits 0 and 1, where each position represents a power of two. It suits computers because circuits have two stable states.

Hexadecimal

A base-16 number system using digits 0-9 and letters A-F. One hexadecimal digit represents exactly four binary bits, so it gives compact notation for memory addresses and colour codes.

Two's complement

A method of representing signed binary integers in which the most significant bit indicates a negative value, allowing subtraction to be performed by addition of the complement.

ASCII

A character coding scheme using 7 bits to represent 128 characters including upper and lower case letters, digits and control codes. Extended versions use 8 bits.

Unicode

A character encoding standard assigning a unique code point to characters of most of the world's writing systems, enabling consistent multilingual text exchange.

Primary key

A field or combination of fields that uniquely identifies each record in a database table. It cannot contain duplicate values or nulls.

Relational database

A database storing data in tables of rows and columns, linked by keys. Relationships between tables reduce data duplication and support queries across related data.

Data validation

Automated checking that input data is reasonable and within acceptable limits, using rules such as range, type, length and presence checks. It cannot confirm data is accurate.

Data verification

Checking that data has been copied or entered accurately, for example by double entry or proofreading against the original source document.

Encryption

The transformation of readable plaintext into unreadable ciphertext using an algorithm and key, protecting data confidentiality during transmission or storage.

Firewall

Hardware or software that monitors and filters incoming and outgoing network traffic against defined rules, blocking unauthorised access to a private network.

Phishing

A social-engineering attack sending fraudulent messages that impersonate a trusted organisation to trick recipients into revealing passwords or financial details.