Hardware and software Revision Notes

Hardware refers to all the tangible, physical parts of a computer system that you can touch and see. These components work together to perform computing tasks.

The Central Processing Unit (CPU) is the brain of the computer. It executes instructions and processes data. The motherboard is the main circuit board that connects all hardware components, allowing communication between them.

Memory is divided into two main types: RAM (Random Access Memory) and ROM (Read-Only Memory). RAM is volatile memory used to store data and programs temporarily while the computer is on. ROM contains permanent instructions, such as the computer's startup firmware, and is non-volatile, meaning it retains data without power.

• CPU: Executes instructions and processes data.
• Motherboard: Connects all hardware components.
• RAM: Temporary memory for active data and programs.
• ROM: Permanent memory for essential startup instructions.

Beyond the core components, computers include specialised hardware to handle specific tasks. A graphics card processes images and video, improving display quality and performance, especially in gaming or design applications. A sound card manages audio input and output, enabling sound recording and playback.

The Network Interface Card (NIC) allows the computer to connect to a network, such as the internet or a local area network (LAN). Cameras can be built-in or external devices used for capturing images or video.

Storage devices, such as hard drives or solid-state drives, store data and programs permanently. Input devices (like keyboards and mice) allow users to enter data, while output devices (like monitors and printers) display or produce results from the computer.

• Graphics card: Processes images and video.
• Sound card: Manages audio input/output.
• NIC: Connects the computer to networks.
• Camera: Captures images or video.
• Storage devices: Store data permanently.
• Input devices: Enter data (e.g., keyboard, mouse).
• Output devices: Display or produce results (e.g., monitor, printer).

Software consists of sets of instructions (programs) that tell the hardware what to do. It can be divided into two main categories: application software and system software.

Application software helps users perform specific tasks. Examples include word processors for writing documents, spreadsheets for calculations and data analysis, and databases for organising information. Other examples are control and measurement tools used in scientific experiments, applets which are small applications embedded in web pages, video, graphics and audio editors for multimedia creation, and CAD (Computer-Aided Design) software used in engineering and architecture.

• Application software: Programs for specific user tasks.
• Examples: Word processors, spreadsheets, databases, control tools, applets, multimedia editors, CAD.

System software manages the computer hardware and provides a platform for application software to run. The operating system (OS) is the most important system software; it controls hardware resources, manages files, and provides user interfaces.

Other system software includes device drivers, which allow the OS to communicate with hardware devices like printers or graphics cards. Compilers translate programming code into machine code the CPU can execute. Linkers combine different pieces of code into a single program. Utilities are small programs that perform maintenance tasks such as virus scanning or disk cleanup.

• Operating system: Manages hardware and user interface.
• Device drivers: Enable communication with hardware devices.
• Compilers: Translate code into machine language.
• Linkers: Combine code modules.
• Utilities: Perform maintenance tasks.

Data can be represented in two main forms: analogue and digital. Analogue data is continuous and can take any value within a range, such as sound waves or temperature readings. Digital data is discrete, represented by binary values (0s and 1s), which computers use internally.

Computers process only digital data. Therefore, analogue data must be converted into digital form before processing. This is done using an Analogue-to-Digital Converter (ADC), which samples the analogue signal at intervals and converts these samples into binary numbers.

Conversely, when digital data needs to control analogue devices like speakers or monitors, it must be converted back into analogue signals using a Digital-to-Analogue Converter (DAC). This ensures the device receives a continuous signal it can interpret.

• Analogue data: Continuous signals (e.g., sound waves).
• Digital data: Discrete binary values (0s and 1s).
• Analogue-to-Digital Conversion: Converts continuous signals into digital form for processing.
• Digital-to-Analogue Conversion: Converts digital data back to continuous signals to control devices.