MATSEC SEC Information Technology flashcards

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

Data versus information

Data are raw, unprocessed facts such as numbers or text. Information is data that has been processed, organised and given context so it becomes meaningful to a person using it.

Fetch-decode-execute cycle

The CPU repeatedly fetches an instruction from memory, decodes it in the control unit, executes it in the ALU, and stores the result back to memory or a register before starting again.

Volatile memory

Memory that loses its stored contents when electrical power is removed. RAM is volatile and holds the programs and data currently in use by the processor.

ROM and firmware

Read-only memory is non-volatile and retains data without power. It typically stores firmware such as the BIOS or UEFI program that starts the computer during boot.

Operating system functions

The operating system manages memory allocation, schedules processor time, controls file storage, handles input and output devices, and provides the user interface and security features.

System versus application software

System software, including the operating system, utilities and drivers, runs and maintains the computer. Application software such as a spreadsheet performs tasks the user directly wants to accomplish.

Lossy versus lossless compression

Lossless compression, as in ZIP or PNG, restores the original data exactly. Lossy compression, as in JPEG or MP3, permanently discards some detail to achieve much smaller files.

Validation checks

Rules applied to input to reject unacceptable data: range check, type check, presence check, format check, length check and check digit. They cannot detect a plausible but incorrect value.

Verification methods

Techniques confirming data was entered or transferred correctly, such as double entry (typing twice and comparing), visual checking against the source document, and parity checks in transmission.

LAN versus WAN

A local area network covers a small area such as one building and is usually privately owned. A wide area network spans large distances and typically uses third-party communication links.

Star topology

Each device connects to a central switch or hub. Failure of one cable affects only that device, but failure of the central device disables the whole network.

Bandwidth versus latency

Bandwidth is the maximum amount of data a channel can carry per unit time, usually measured in Mbps. Latency is the delay before data transfer begins, measured in milliseconds.

IP address and DNS

An IP address uniquely identifies a device on a network. The Domain Name System translates human-readable domain names into IP addresses so browsers can locate servers.

Client-server versus peer-to-peer

In client-server, central servers provide services and control access. In peer-to-peer, each computer shares files directly with others, with no dedicated central server.

Binary and denary conversion

Denary values convert to binary by repeatedly dividing by two and reading remainders upwards. Binary converts back by summing place values 128, 64, 32, 16, 8, 4, 2, 1.

Bits, bytes and storage units

One byte equals eight bits. Storage scales by 1024: 1024 bytes in a kilobyte, 1024 kilobytes in a megabyte, 1024 megabytes in a gigabyte and 1024 gigabytes in a terabyte.

Primary versus secondary storage

Primary storage such as RAM is directly accessed by the CPU and is fast but volatile. Secondary storage such as SSD or hard disk is non-volatile and retains data permanently.

Database record and field

A database table stores data in records (rows) and fields (columns). A field holds one attribute of a record, and a primary key uniquely identifies each record.

Relational database relationships

Tables link through keys: a primary key uniquely identifies a record, while a foreign key in another table references that primary key to create one-to-many or many-to-many relationships.

SQL SELECT query

A SELECT statement retrieves data: SELECT fields FROM table WHERE condition. WHERE filters records, ORDER BY sorts results, and wildcards like * return all fields.

Spreadsheet relative and absolute references

A relative reference such as A1 adjusts when copied to another cell. An absolute reference such as $A$1 stays fixed, which is essential when referring to a constant cell.

Spreadsheet formulas and functions

A formula begins with = and performs calculation using cell references and operators. Functions such as SUM, AVERAGE, IF and COUNT perform predefined calculations on ranges of cells.

Word processing features

Features include styles for consistent headings, mail merge to produce personalised letters from a data source, templates, tables of contents, spell check and page layout settings.

Malware types

Malicious software includes viruses that attach to files, worms that self-replicate across networks, trojans disguised as legitimate programs, spyware that collects data, and ransomware that encrypts files for payment.

Phishing

A social engineering attack using fraudulent emails, messages or websites that impersonate trusted organisations to trick users into revealing passwords, card details or other sensitive information.

Firewall

Hardware or software that monitors and filters incoming and outgoing network traffic against rules, blocking unauthorised access while permitting traffic that matches allowed criteria.

Encryption

The conversion of plaintext into ciphertext using an algorithm and key so that intercepted data cannot be read. Only someone holding the correct key can decrypt it back.

Strong password practice

Use long passphrases mixing upper and lower case, digits and symbols, avoid dictionary words and personal details, use a different password per account, and enable two-factor authentication where offered.

Backup strategies

Regular backups copy data to separate media or cloud storage. Full backups copy everything; incremental backups copy only changes since the last backup, saving time and space.

The Data Protection Act principles

Personal data must be processed lawfully and fairly, used only for stated purposes, adequate and relevant, accurate, kept no longer than necessary, processed per data subject rights, and kept secure.

System development life cycle

Stages: analysis of requirements, design, implementation (coding), testing, deployment and maintenance. Iterative and agile approaches repeat stages in short cycles rather than once sequentially.

Testing types

Unit testing checks individual components, integration testing checks components working together, system testing checks the whole system, and acceptance testing confirms it meets user requirements.