Computer Basics and Hardware

Definition: A computer is an electronic device that accepts data (input), processes it, stores it, and produces information (output).

Core Parts

• CPU (Central Processing Unit) — the "brain"; has the ALU (arithmetic & logic) and Control Unit.
• Input devices — keyboard, mouse, scanner.
• Output devices — monitor, printer, speakers.
• Storage — hard disk, SSD, pen drive.

Hardware vs Software

• Hardware — the physical parts you can touch.
• Software — the programs and instructions (system and application software).

Real-world example: When you type a document, the keyboard is input, the CPU processes it, the screen is output, and the disk stores the file.

Example 1. The "brain" of the computer is the:

• CPU (Central Processing Unit).

Example 2. Which of these is an input device: monitor, printer, keyboard, speaker?

• Keyboard.

Example 3. The ALU inside the CPU performs:

• Arithmetic and logical operations.

Quick-revision notes for Computer Basics and Hardware — the must-know points for SSC CGL Tier-I/II.

• A computer processes data using input, processing (CPU), storage, and output units.
• The CPU (Central Processing Unit) has the ALU (arithmetic/logic) and CU (control unit); it is the "brain".
• Input devices: keyboard, mouse, scanner; output devices: monitor, printer, speaker.
• Hardware is the physical parts; software is the set of programs/instructions.
• The motherboard connects all components; the CPU and RAM plug into it.
• The IPO cycle = Input → Process → Output (with storage supporting it).

Cover the answer, recall, then check. 6 cards on the must-know Computer Basics and Hardware facts for SSC CGL.

Q1. What are the two main parts of the CPU?
A1. The ALU (Arithmetic Logic Unit) and the CU (Control Unit).

Q2. Name three input devices.
A2. Keyboard, mouse, and scanner.

Q3. What is the difference between hardware and software?
A3. Hardware is the physical components; software is the set of programs/instructions.

Q4. Which component is called the "brain" of the computer?
A4. The CPU (Central Processing Unit).

Q5. What does the IPO cycle stand for?
A5. Input, Process, Output.

Q6. Name two output devices.
A6. Monitor and printer.