How does a computer work?
A computer turns instructions into actions by moving information between its input devices, memory, processor, storage, and output devices.
Give it an instruction
An input device sends a signal. Software interprets it as an action, such as opening a document.
Read the complete explanation +
Give it an instruction
An input device sends a signal. Software interprets it as an action, such as opening a document.
Bring the data into memory
The system loads the required program and data from persistent storage into RAM. RAM provides working space for the running program.
Process the instructions
The CPU fetches and decodes instructions, then performs arithmetic, comparisons, or data movement. It works closely with memory.
Show the result
The program sends output to a device. For a display, graphics hardware helps turn the result into the image you see.
Keep what matters
When you save a file, the system writes its data to persistent storage. Unsaved RAM contents are generally lost when power is removed.
About this visual model +
An open desktop computer sits beside a monitor and keyboard. The uncovered case exposes storage, RAM, processor and control circuitry. Connections show the data path in simplified form.
This is a conceptual model. Real computers overlap many operations and use caches, buses, and controllers not shown here.
- Input: A keyboard, mouse, or other input device sends information for the computer to process.
- Storage: Persistent storage holds programs and files even when the power is off.
- Memory: RAM temporarily holds instructions and data that running programs need.
- Processor: The CPU fetches instructions, interprets them, and performs operations on data.
- Output: An output device presents the result, such as pixels on a screen.
- Control: Control circuitry coordinates the movement of data and the execution of instructions.
Further reading: Computer systems organization ↗