Computer Components and Functioning

Computer Components and Functioning

• Computers are a combination of mechanical and electrical parts used to execute programs.
• Program: A set of instructions for a computer to perform a task.
• Programmer: A person who designs, creates, and tests programs.
• Hardware: The physical components of a computer.
• CPU (Central Processing Unit): The component that runs programs.
• Microprocessors: CPUs on small chips.
• Main Memory (RAM): Stores programs and data while running; quickly accessible by CPU; erased when power is off.
• Secondary Storage Devices: Hard drives, SSDs, USBs, etc. hold data long-term. Programs stored here; loaded to RAM when needed.
• Input Devices: Keyboard, mouse, camera—acquire data for the computer. Disk drive acts as an input device when loading programs.
• Output Devices: Printer, monitor, speaker—provide output to other devices. Disk drive/USB can be output device when data is sent.
• Communication Devices: Modems, routers, hubs—connect computers and devices.
• Software: Controls everything a computer does.
• Application Software: Programs for everyday tasks (e.g., word processing, web browsers).
• System Software: Controls basic computer operations.
  • Operating System: Windows, macOS, Android, iOS—manages hardware, connected devices, storage, and program execution.
  • Utility Programs: Virus scanners, file compression, data backup—enhance computer operation and data safety.
  • Software Development Tools: Compilers, assemblers, interpreters—used to create, edit, and test programs
  • BIOS (Basic Input Output System): Firmware (stored on ROM) initialises hardware and manages data flow to/from OS during boot.

Data Storage and Representation

• All computer data is stored as 0s and 1s.
• Byte: Enough memory for a letter or small number (8 bits).
• Bit: An on/off switch; electrical component holding a positive or negative charge.
• Binary Numbering System: Represents numbers using 0s and 1s.
• Byte Size Limits: A single byte can hold values 0-255; two bytes, 0-65535.
• Digital Data: Data represented in binary numbers.
• Digital Images: Composed of pixels; each pixel's color is converted to a binary number.
• Digital Music: Composed of samples; each sample is converted to a binary number.

Program Execution

• CPU Operations: Performs simple operations (reading, adding, subtracting etc) on data; each CPU has a specific instruction set.

• Program Execution Cycle: Fetch, decode, and execute instructions.

• Fetching: Reading next instruction from memory.

• Decoding: Identifying the operation to perform.

• Executing: Performing the operation.

• Program Loading: Programs must be copied to RAM each time the CPU uses them.

Programming Languages

• Low-Level Languages: Machine language (binary), assembly language. Very close to the computer.
• Assembly Language: Uses mnemonics (short words) for instructions—easier than machine language.
• Assembler: Translates assembly language to machine language.
• High-Level Languages: Allow for creating complex programs without deep CPU knowledge; more intuitive than low-level languages.
• Keywords: Predefined words in high-level languages with specific meanings.
• Operators: Perform operations on data (e.g., mathematical operations).
• Syntax: Rules for writing programs (correct structure of commands).
• Statements: Individual instructions in high-level programming languages.

Analogy

• CPU is like a worker in a shed.
• Hard drive are the shelves storing tools.
• RAM is the workbench for tools the worker currently needs.
• More tools available (bigger hard drive)= faster work (faster computer).

Learn about the fundamental components of a computer, including the CPU, memory, storage, and input/output devices. Understand hardware, software, and the role of programmers. Discover how these elements work together to execute programs.