HSSC CET · Bite-size lessons

Computer Fundamentals

About 6 min · Computer Knowledge · English

Time worked out from the lesson's 408 words at 150 words a minute, plus a minute for each question.

Computer Fundamentals is a foundational topic in the HSSC CET that tests your understanding of how computers work at a basic level.

Key ideas

• Computer Definition: An electronic device that accepts data (input), processes it according to instructions (program), and produces results (output). It follows the IPO cycle: Input → Process → Output.
• Hardware vs Software: Hardware refers to physical, tangible components (keyboard, monitor, CPU). Software refers to programs and instructions that tell hardware what to do.
• Types of Computers by Size: Supercomputer (fastest, used for scientific research) → Mainframe (large organisations, banking) → Minicomputer → Microcomputer (personal computers, laptops).
• Generations of Computers: First (vacuum tubes) → Second (transistors) → Third (integrated circuits) → Fourth (microprocessors) → Fifth (artificial intelligence, current era).
• Central Processing Unit (CPU): The "brain" of the computer with three parts—ALU (Arithmetic Logic Unit for calculations), CU (Control Unit for coordination), and Registers (temporary storage).

Watch out for

• Confusing RAM and ROM → RAM is temporary (working memory), ROM is permanent (stores startup instructions). Remember: RAM = "Running Applications Memory" (volatile); ROM = "Read Only, permanent."
• Mixing up Input and Output devices → Ask: "Does it send data TO the computer or receive data FROM the computer?" Scanner sends (input), printer receives (output).
• Using 1000 instead of 1024 → In computing, memory units follow binary: 1 KB = 1024 bytes, not 1000. However, storage manufacturers sometimes use 1000 (decimal), causing confusion.

Quick reference

• IPO Cycle: Input → Process → Output (fundamental computing model)
• 1 Byte = 8 Bits; 1 KB = 1024 Bytes; 1 MB = 1024 KB; 1 GB = 1024 MB
• CPU = ALU + CU + Registers (Arithmetic Logic Unit, Control Unit, Registers)
• RAM = Volatile (temporary) | ROM = Non-volatile (permanent, stores BIOS)
• 5 Generations: Vacuum Tubes → Transistors → ICs → Microprocessors → AI

Check yourself: 3 questions

This lesson is cut from the topic's note, not rewritten. Fact-checked on 18 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.

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