Cheat sheet · Class 11 · CBSE · Science Computer Science
Computer System cheat sheet
The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.
CBSE Class 11 · Computer Science
Cheat sheet
Chapter 1Computer System
Input → Process → Output, with Storage alongside (IPOS).
1. Components
- Input devices: keyboard, mouse, scanner, microphone.
- CPU: ALU (calculations) + Control Unit (directs) + registers.
- Output devices: monitor, printer, speaker.
- Memory stores data and instructions.
2. Memory
| Type | Examples | Nature |
|---|---|---|
| Registers / cache | CPU cache L1–L3 | fastest, smallest |
| Primary | RAM (volatile), ROM (non-volatile) | directly accessed by CPU |
| Secondary | HDD, SSD, pen drive, CD | permanent, larger, slower |
Units: 1 nibble = 4 bits; 1 byte = 8 bits; 1 KB = 1024 B; then MB, GB, TB, PB.
3. Software
System software
OS, device drivers, utilities.
Language translators
Assembler, compiler (whole program), interpreter (line by line).
Application software
General purpose (word processor) or customised (billing).
4. Operating System
- Manages processes, memory, files, devices.
- User interfaces: CLI, GUI, touch, voice.
5. Key Points
- Data bus, address bus, control bus.
- Microprocessor = CPU on a chip.
- Open-source software: source code is free to view/modify.
- Free ≠ always open source.
Remember: IPOS | memory hierarchy | system vs application software
Computer System: questions and notes
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