IGCSE ICT Complete Study Notes Flashcards

Comprehensive question-and-answer study flashcards based on the Cambridge IGCSE ICT study notes covering hardware, software, networking, systems life cycle, security, and terminology.

What is the primary distinction between hardware and software?

Hardware refers to the physical, tangible components of a computer system that can be touched, whereas software consists of programs and instructions that control hardware and perform tasks without physical form.

What are the key functions of an Operating System (OS)?

Managing memory, managing peripherals via device drivers, managing files, providing a user interface (CLI or GUI), providing security via user accounts, and managing multitasking.

What is an embedded system?

A computer system built into a larger device (such as a washing machine, microwave, or car engine management system) to perform a specific, dedicated function that cannot normally be reprogrammed by the end user.

What is the function of the Program Counter (PC) register in the CPU?

It holds the memory address of the next instruction to be fetched.

What sequence of events occurs during the fetch phase of the CPU fetch-decode-execute cycle?

The address in the PC is copied to the MAR, the instruction at that memory address is fetched into the MDR while the PC increments, and the instruction is then moved into the CIR.

How does virtual memory function when RAM becomes full?

The operating system temporarily moves less recently used data from RAM to an area of the hard disk, freeing up RAM for immediate tasks, and swaps data back into RAM when needed again.

What is the difference between batch processing and real-time processing?

Batch processing collects data over a period and processes it all at once without user interaction, whereas real-time processing processes data immediately upon input to affect or control an ongoing process directly.

Why is an Analogue-to-Digital Converter (ADC) required when connecting analogue sensors to a computer?

An ADC converts continuous analogue electrical signals from sensors into digital signals that the computer processor can read and process.

What are the typical storage capacities of a CD, a single-layer DVD, and a single-layer Blu-ray disc?

A CD holds approximately $700\,MB$, a single-layer DVD holds approximately $4.7\,GB$, and a single-layer Blu-ray disc holds approximately $25\,GB$.

What is the difference between a full backup and an incremental backup?

A full backup creates a complete copy of all data, whereas an incremental backup only copies data that has changed since the last backup occurred.

How does a network switch differ in operation from a network hub?

A hub broadcasts incoming data to all devices on a network regardless of recipient, whereas a switch examines the MAC address of incoming data and sends it specifically to the intended device.

What is the distinction between an IP address and a MAC address?

An IP address is a logical numerical address used to route data across networks and can be static or dynamic, while a MAC address is a permanent physical address assigned to a NIC by its manufacturer.

What health issue is caused by sitting still for extended periods, and how can it be prevented?

It causes Deep Vein Thrombosis (DVT); it can be prevented by taking regular breaks to walk around and ensuring adequate legroom.

How does a feedback loop operate in a computerised control system?

Sensors continuously take readings, convert them via an ADC, and send them to a microprocessor that compares them against pre-set limits; if values are out of range, actuators make adjustments, and new sensor readings are continuously fed back.

What are the four primary components of an expert system?

The Knowledge base, Inference engine, Rules base, and User interface.

What is the Hawthorne effect in the context of systems analysis observation?

It is the phenomenon where individuals being observed alter their behaviour or work harder than usual simply because they know they are being watched.

What is extreme test data?

Valid test data located at the absolute upper or lower boundary limits of an acceptable range, used to confirm validation rules handle limits correctly.

Why is parallel changeover considered safer than direct changeover?

Because both old and new systems run simultaneously, ensuring the old system remains available as an active backup if the new system fails.

How do phishing and pharming differ from each other?

Phishing relies on fraudulent emails tricking users into revealing sensitive data or clicking malicious links, whereas pharming uses malicious code or DNS corruption to automatically redirect users to fake websites without user action.

What is the distinction between a computer virus and a computer worm?

A virus attaches to legitimate files/programs and requires execution or human action to spread, whereas a worm is standalone malware that replicates and spreads independently across networks.

What are the three factor categories used in multi-factor authentication (MFA)?

Something you know (such as a password or PIN), something you have (such as a security token or smart card), and something you are (biometric data).

What is the difference between lossless and lossy file compression?

Lossless compression reduces file size without discarding any data so the file can be perfectly reconstructed, whereas lossy compression permanently removes less perceptible data to achieve smaller file sizes.

Why can vector graphics be scaled indefinitely without loss of quality?

Vector graphics are defined by mathematical formulas and paths that recalculate shapes automatically when resized, unlike bitmap graphics which rely on a fixed grid of pixels.

What is a house style and what is its primary benefit?

A house style is a set of consistent design rules (fonts, colours, logos) applied across all company publications to create a recognizable, unified brand identity.

Why is manual proofreading necessary despite the availability of automated spell and grammar checkers?

Automated tools cannot reliably detect correct words used in wrong contexts (homophones), factual errors, or awkward phrasing that is grammatically valid.

What is the relationship between data, information, and knowledge?

Data consists of raw, unprocessed facts without context; information is data processed to give it meaning; knowledge is the understanding gained from combining information with experience to make decisions.

How does data validation differ from data verification?

Validation is an automated software check ensuring data entered is reasonable, plausible, and follows rules, whereas verification checks that data accurately matches its original source.

How does a check digit function as a validation method?

A check digit is an extra digit calculated mathematically from the other digits in a code (such as a barcode) to detect entry or transmission errors.

What is the difference between CAD and CAM in manufacturing?

CAD (Computer-Aided Design) is software used to create precise technical 2D or 3D drawings, while CAM (Computer-Aided Manufacture) uses computers to control machinery to physically manufacture the product.

What is the difference between technical documentation and user documentation?

Technical documentation contains code listings, system flowcharts, and file structures intended for IT professionals maintaining the system, whereas user documentation provides operational instructions, FAQs, and tutorials for end users.