O Level Computer Hardware Flashcards

Flashcards based on lecture notes about Computer Hardware.

Central Processing Unit (CPU)

The CPU is responsible for the execution and processing of all instructions and data in a computer. It consists of the control unit (CU), arithmetic and logic unit (ALU), registers, and buses.

Microprocessor

An integrated circuit (microchip) containing the ALU and control unit, enabling it to interpret and execute instructions and carry out arithmetic operations.

Von Neumann Architecture

A computer architecture based on the idea of a stored program computer, featuring a central processing unit (CPU), direct memory access for the processor, storage of programs and data in computer memories, and sequential execution of instructions.

Arithmetic & Logic Unit (ALU)

A component of the CPU that performs arithmetic (e.g., +, -, shifting) and logic (e.g., AND, OR) operations.

Control Unit (CU)

A component of the CPU that reads instructions from memory, interprets them using the Fetch-Decode-Execute cycle, and generates control signals to other components.

Program Counter (PC)

A register that stores the address of the next instruction to be read from memory.

Current Instruction Register (CIR)

Stores the current instruction being decoded and executed.

Memory Address Register (MAR)

Stores the address of the memory location currently being read from or written to.

Memory Data/Buffer Register (MDR/MBR)

Stores data which has just been read from memory or data which is about to be written to memory.

System Buses

Connect the CPU to memory and input/output devices, including the address bus, data bus, and control bus.

Address Bus

A unidirectional bus that carries addresses throughout the computer system, determining the number of memory locations that can be directly addressed.

Data Bus

A bidirectional bus that carries data between the CPU, memory, and input/output devices, with the width determining the word length that can be transported.

Control Bus

A bidirectional bus that carries signals from the CU to all other computer components, typically 8-bits wide, used for control signals.

Fetch-Decode-Execute Cycle

The process by which the CPU carries out instructions, involving fetching data and instructions from memory, decoding each instruction, and then executing it.

Cache Memory

A high-speed memory that stores frequently used instructions and data for faster access, improving processor performance.

Cores

Independent processing units within a CPU (ALU, CU, and registers) that can improve computer performance, such as dual-core or quad-core processors.

Instruction Set

A set of operations decoded in sequence by a computer system, consisting of an opcode (specifying the operation) and an operand (the data or register to be acted on).

Embedded System

A combination of hardware and software designed to carry out a specific set of functions, often based on microcontrollers, microprocessors, or system on chips (SoC).

Barcode Readers

Scanners that use a red laser or LED light source to read barcodes, which represent digits 0 to 9 as a series of dark and light parallel lines, used for identifying items and automatic stock control.

QR Codes

A type of barcode made up of a matrix of filled-in dark squares on a light background, holding more information than traditional barcodes and read by a camera on a smartphone or tablet.

Digital Cameras

Cameras that capture images on photodiodes (CCD) and convert them into pixels, forming an electronic matrix of the image, often used with microprocessors to control camera functions.

Keyboards

Common data entry devices, either physical (USB or Bluetooth) or virtual (touchscreen), where each character has an ASCII value that the computer detects.

Microphones

Devices that convert sound into electric currents of varying amplitude, used for inputting text, voiceovers, and as sensors.

Optical Mouse

A pointing device that uses tiny cameras and a red LED light source to calculate its position, offering more reliability and working on any surface compared to a mechanical mouse.

2D Scanners

Devices used to scan documents and convert the information into an electronic format, often used with OCR software to convert scanned text into a text file.

3D Scanners

Devices that scan solid objects and produce a 3D image, used in CAD software and 3D printing, using lasers, X-rays, magnetic resonance, or white light.

Touchscreens

Input devices that allow users to interact with a device by touching the screen, using technologies like capacitive, infrared, and resistive touchscreens.

Actuators

Mechanical or electromechanical devices, such as relays, solenoids, or motors, used to control a process (e.g., starting/stopping a conveyor belt or opening/closing a valve).

Speakers

Output devices that produce sound from varying electric currents, using a paper/plastic cone, permanent magnet, and coil of wire.

Light Projectors

Devices used to project computer output onto a larger screen, using technologies like digital light processing (DLP) or liquid crystal display (LCD).

Inkjet Printers

Printers that rely on spraying liquid ink droplets onto paper, using thermal bubble or piezoelectric technology.

Laser Printers

Printers that rely on using dry powder ink (toner) melted onto the paper using a fuser.

3D Printers

Printers that produce solid objects by building up very thin layers of material, such as powdered resin, powdered metal, paper, or ceramics.

Sensors

Input devices that read physical properties from their surroundings (e.g., temperature or light) and send signals to a microprocessor, often through an ADC.

Primary Memory

Memory that is directly accessible by the CPU, including RAM (Random Access Memory) and ROM (Read-Only Memory).

Secondary Storage

Non-volatile storage devices (e.g., HDD, SSD) that store data for as long as required by the user, not directly addressable by the CPU.

RAM (Random Access Memory)

Volatile memory that the CPU can access and modify. Used as the working area of the computer where data currently being used is temporarily stored.

ROM (Read-Only Memory)

Non-volatile memory that can only be read. Contains data that can't be changed and needs to be stored permanently (e.g., start-up routines).

Magnetic Storage

Secondary storage which stores data on platters coated in a magnetisable material, using read/write heads to access data in sectors and tracks.

Solid-State Storage

Secondary storage which controls the movement of electrons within NAND or NOR chips, storing data as 0s or 1s in tiny transistors.

Optical Storage

Secondary storage which uses laser light to read and write data on the disk surface, storing data in pits and lands.

Virtual Memory

A memory management technique that uses both RAM (physical memory) and swap space on a secondary storage device (HDD or SSD) to give the illusion of unlimited RAM.

Cloud Storage

Storing vast quantities of data on remote physical servers, with different types like public, private, and hybrid clouds.

Network Interface Card (NIC)

A hardware component needed to allow a device to connect to a network (e.g., the internet), containing the Media Access Control (MAC) address.

MAC Address

A unique identifier assigned to a network interface card (NIC) for communication within a network.

IP Address

A numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.

Routers

Networking devices that forward data packets between computer networks, ensuring data reaches its intended destination.