MATSEC IM Information Technology flashcards

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

Data

Raw, unprocessed facts, symbols or signals with no context, such as a list of numbers or characters captured by an input device.

Information

Data that has been processed, organised and given context so that it is meaningful and useful to the person receiving it.

Information processing cycle

The sequence input, processing, output and storage, with feedback for control, describing how a system converts raw data into useful information.

Control unit

CPU component that fetches instructions from memory, decodes them, and generates control signals that coordinate the other parts of the processor.

ALU

Arithmetic Logic Unit; the CPU component that performs arithmetic operations such as addition and logic operations such as AND, OR and comparison.

Von Neumann architecture

Design in which program instructions and data share the same main memory and are fetched one at a time over a shared bus.

Cache memory

Small, fast memory between the CPU and main memory that holds recently or frequently used instructions and data to reduce average access time.

RAM

Random Access Memory; volatile main memory that holds programs and data currently in use and loses its contents when power is removed.

ROM

Read Only Memory; non-volatile memory whose contents are retained without power and typically hold firmware such as the bootstrap loader.

Storage capacity units

Binary units where 8 bits make a byte, 1024 bytes make a kilobyte, and 1024 of each unit makes the next: megabyte, gigabyte, terabyte.

System software

Software that manages hardware and provides a platform for applications, including operating systems, utilities, device drivers and language translators.

Operating system

System software that manages processes, memory, files and devices, enforces security, and provides a user interface for running application programs.

Compiler

Translator that converts an entire source program into object code before execution, reporting all errors together and producing a fast executable.

Interpreter

Translator that converts and executes a source program one statement at a time, stopping at the first error and requiring the translator at run time.

Validation check

Automated test that data is reasonable and acceptable, using type, range, presence, length or format checks, but which cannot confirm the data is correct.

Verification

Method of confirming data accuracy by comparing it with an independent source, for example double entry or visual proofreading of input.

Primary key

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

Foreign key

Field in one table that stores the primary key value of another table, creating a relationship and enforcing referential integrity between the tables.

First normal form

Normalisation stage in which every field holds a single atomic value and repeating groups are removed, so each row-column intersection has one value.

SQL SELECT

Statement that retrieves rows from a table, specifying columns, a source table and optional WHERE, ORDER BY and GROUP BY clauses.

Sequential file access

File organisation in which records are stored and read in key order one after another, efficient for batch processing but slow for single-record lookup.

Star topology

Network layout in which every device connects to a central hub or switch; easy to fault-find, but the central device is a single point of failure.

LAN

Local Area Network; a network covering a limited area such as a room, building or campus, usually owned and managed by one organisation.

DNS

Domain Name System; a distributed service that translates human-readable domain names into the numeric IP addresses used to route packets.

DHCP

Dynamic Host Configuration Protocol; a service that automatically assigns IP addresses, subnet masks and gateways to devices joining a network.

Fibre optic cable

Transmission medium carrying data as pulses of light along glass or plastic strands; high bandwidth and immune to electromagnetic interference.

Bandwidth

The range of frequencies a channel can carry, or its maximum data-carrying capacity, usually expressed in bits per second.

Worm

Self-replicating malware that spreads across networks without attaching to a host file and without requiring user action to propagate.

Trojan horse

Malware disguised as legitimate software that the user is tricked into installing, giving an attacker unauthorised access or control.

Phishing

Fraudulent messages that impersonate a trusted party to trick recipients into revealing credentials or clicking malicious links.

Firewall

Hardware or software that filters network traffic against rules, allowing or blocking packets by address, port or protocol.

Symmetric encryption

Encryption in which the same secret key encrypts and decrypts data; fast, but both parties must securely share the key.