What is a Computer?
A computer is an electronic machine that receives data, processes that data according to instructions, stores information and produces useful results. The information entered into a computer is commonly called input, while the result produced by the computer is called output.
Modern computers can perform billions or even trillions of operations in a short period of time. They are used for communication, education, entertainment, scientific research, engineering, banking, business, medicine, transportation, programming and countless other activities.
The basic computer cycle
Input
Data is provided to the computer using devices such as keyboards, mice, cameras, microphones and touchscreens.
Processing
The processor and other components manipulate the input according to instructions.
Storage
Data and programs can be stored temporarily or permanently.
Output
The computer presents results through displays, speakers, printers and other output devices.
Data and Information
Data is raw information such as numbers, characters, images, sounds or measurements. When data is processed and given useful meaning, it becomes information. Computers can process many different types of data because internally digital systems represent information using binary values.
History & Generations of Computers
Computers have changed dramatically over time. Early machines were enormous, expensive and limited in capability. Modern computers can fit inside smartphones, watches and other small devices while providing enormous computing power.
Major generations
First Generation
Early electronic computers used vacuum tubes. They were very large, generated significant heat and consumed large amounts of electricity.
Second Generation
Transistors replaced vacuum tubes in many systems. Computers became smaller, faster and more reliable.
Third Generation
Integrated circuits allowed many electronic components to be placed together on chips.
Fourth Generation
Microprocessors placed the central processing functions onto highly integrated chips, enabling personal computers.
The modern era includes highly integrated processors, graphics processors, mobile computing, cloud computing, artificial intelligence and specialized hardware. The idea of "generations" is useful for understanding history, although modern technology does not always fit neatly into a single generation.
Computer Hardware
Hardware means the physical components of a computer. Hardware can be touched or physically installed. A complete computer system contains many different hardware components, each with a specific purpose.
CPU
Performs general-purpose processing and executes program instructions.
RAM
Provides fast temporary working memory for programs and active data.
Storage
Stores the operating system, applications and personal files for longer-term use.
Motherboard
Connects major components and allows them to communicate.
GPU
Performs graphics and highly parallel computational tasks.
Power Supply
Converts and distributes electrical power to computer components.
CPU — Central Processing Unit
The CPU is one of the most important components of a computer. It executes instructions from programs and performs operations on data. The CPU communicates with memory and other components through the computer's architecture and interconnection systems.
What does a CPU do?
- Fetches instructions.
- Decodes instructions.
- Performs calculations and logical operations.
- Moves data between different parts of the system.
- Controls many computational activities.
CPU cores
A CPU core is an execution unit capable of processing instructions. Modern processors commonly contain multiple cores. Multiple cores can allow a computer to handle multiple threads of work more effectively, depending on the software and workload.
Clock speed
CPU clock speed is commonly expressed in GHz. It describes the frequency of the processor's clock, but clock speed alone does not determine overall performance. Architecture, instructions per cycle, cache, core count, workload and many other factors also matter.
CPU cache
CPU cache is very fast memory located close to or inside the processor. It stores frequently needed data and instructions so the CPU can access them more quickly than if it always had to retrieve them from slower memory.
| Term | Meaning |
|---|---|
| Core | An execution unit inside a processor. |
| Clock Speed | Frequency of the processor clock. |
| Cache | Very fast memory used to reduce data access delays. |
| Thread | A sequence of instructio |