📑 Topics on this page (Jump to Topic):
📌 1. What is a Computer?
- A computer is an electronic machine that accepts data as input, processes it according to instructions (a program) and gives information as output. "Compute" means to calculate.
- Data = raw facts, e.g. 45, 67. Information = processed, meaningful data, e.g. "average 56".
- IPO cycle: Input → Process → Output (+ Storage).
- GIGO = Garbage In, Garbage Out — wrong input gives wrong output.
| Part | Meaning | Example |
|---|---|---|
| Hardware | Physical parts that can be touched | Keyboard, CPU, Monitor |
| Software | Set of programs/instructions | Windows, MS Word, Compiler |
| Firmware | Software permanently stored in a ROM chip | BIOS |
| Liveware / Humanware | People who use the computer | Operator, programmer |
Characteristics of a Computer
| Characteristic | Meaning |
|---|---|
| Speed | Very fast calculation (micro/nano/pico seconds) |
| Accuracy | Almost error-free with correct input |
| Diligence | Works continuously without tiredness |
| Versatility | Can do many different types of tasks |
| Storage | Stores and recalls large amounts of data |
| No IQ | Cannot take decisions on its own |
| No Feelings | No judgment based on emotions |
⚠️ Exam Traps:
- Working continuously without tiring = Diligence, not Speed.
- A compiler is software, not hardware. BIOS = Firmware.
📌 2. Types of Computers
| Basis | Types |
|---|---|
| Working principle | Analog (continuous quantities — temperature, pressure), Digital (works on 0/1), Hybrid (both — e.g. ICU machines) |
| Size/capacity | Supercomputer > Mainframe > Minicomputer > Microcomputer (PC, laptop) |
| Purpose | General purpose (many tasks) and Special purpose (one task, e.g. ATM) |
- Supercomputer speed is measured in FLOPS (Floating Point Operations Per Second). Uses: weather forecasting, nuclear research.
- India's first supercomputer: PARAM 8000 (1991), C-DAC Pune, led by Dr. Vijay Bhatkar.
- World's first supercomputer: CDC 6600 (1964), Seymour Cray (Father of Supercomputing).
- The first computer installed in India was HEC-2M (1956) at ISI Kolkata. The first computer built in India was TIFRAC (TIFR).
⚠️ Exam Traps:
- PARAM is India's first supercomputer, not India's first computer.
📌 3. History & Important "Fathers"
| Device/Invention | Inventor | Year/Fact |
|---|---|---|
| Abacus | China (ancient) | First calculating device |
| Napier's Bones | John Napier | 1617 |
| Pascaline | Blaise Pascal | 1642, first mechanical calculator (add/subtract) |
| Stepped Reckoner | Gottfried Leibniz | could multiply/divide |
| Jacquard Loom | Joseph Marie Jacquard | used punched cards (1801) |
| Difference / Analytical Engine | Charles Babbage | Analytical Engine — basis of the modern computer |
| First programmer | Ada Lovelace | algorithm for the Analytical Engine |
| Tabulating Machine | Herman Hollerith | 1890 US census; company later became IBM |
| Mark I | Howard Aiken (IBM) | 1944, electromechanical |
| ENIAC | J. Presper Eckert & John Mauchly | 1946, first general-purpose electronic digital computer |
| UNIVAC I | Eckert & Mauchly | 1951, first commercial computer |
| Title | Person |
|---|---|
| Father of Computer | Charles Babbage |
| Father of modern computer science | Alan Turing |
| Father of Artificial Intelligence (coined the term) | John McCarthy |
| Father of the Internet | Vint Cerf (& Bob Kahn) |
| Inventor of WWW | Tim Berners-Lee |
| Father of e-mail | Ray Tomlinson |
| Inventor of the mouse | Douglas Engelbart |
| Father of Indian supercomputer | Dr. Vijay Bhatkar |
| Stored-program concept | John von Neumann |
⚠️ Exam Traps:
- Internet (Vint Cerf) ≠ WWW (Tim Berners-Lee).
- Mark I (1944) was electromechanical; ENIAC was the first fully electronic general-purpose computer.
📌 4. Generations of Computers
| Generation | Period (approx.) | Main technology | Examples |
|---|---|---|---|
| 1st | 1940–1956 | Vacuum Tube | ENIAC, EDVAC, UNIVAC |
| 2nd | 1956–1963 | Transistor | IBM 1401, IBM 7094 |
| 3rd | 1964–1971 | Integrated Circuit (IC) | IBM 360 |
| 4th | 1971–present | Microprocessor (VLSI) | Intel 4004, PCs, laptops |
| 5th | Present & future | Artificial Intelligence, ULSI, parallel processing | Robotics, expert systems |
- The transistor was invented in 1947 at Bell Labs (Bardeen, Brattain, Shockley).
- The IC was invented by Jack Kilby (Texas Instruments) and Robert Noyce.
- The first microprocessor was the Intel 4004 (1971), 4-bit.
💡 Memory Tip: Remember the order V-T-I-M-A = Vacuum tube, Transistor, IC, Microprocessor, AI.
⚠️ Exam Traps:
- 3rd generation = IC, 4th = Microprocessor — do not swap them.
- 1st generation mainly used machine language; 2nd used assembly language.
📌 5. Practice MCQs
📝 Practice MCQs (prepared by SF Prep — not PYQs)
Q1. Who is known as the "Father of Computer"? Practice
Correct answer: (B)
Charles Babbage designed the Difference Engine and the Analytical Engine; the Analytical Engine is the basis of the modern computer.
Charles Babbage designed the Difference Engine and the Analytical Engine; the Analytical Engine is the basis of the modern computer.
Q2. Who is regarded as the world's first computer programmer? Practice
Correct answer: (C)
Ada Lovelace wrote the first algorithm for Babbage's Analytical Engine.
Ada Lovelace wrote the first algorithm for Babbage's Analytical Engine.
Q3. What was mainly used in first-generation computers? Practice
Correct answer: (D)
The 1st generation (1940–56) used vacuum tubes, which were large, hot and power-hungry.
The 1st generation (1940–56) used vacuum tubes, which were large, hot and power-hungry.
Q4. Integrated Circuits (ICs) were the main technology of which generation? Practice
Correct answer: (A)
3rd generation (1964–71) = IC. 4th generation = microprocessor.
3rd generation (1964–71) = IC. 4th generation = microprocessor.
Q5. Which was the first microprocessor? Practice
Correct answer: (B)
The Intel 4004 (1971) was the first commercial microprocessor, 4-bit.
The Intel 4004 (1971) was the first commercial microprocessor, 4-bit.
Q6. Fifth-generation computers are mainly based on: Practice
Correct answer: (C)
The 5th generation aims at AI, parallel processing and natural-language understanding.
The 5th generation aims at AI, parallel processing and natural-language understanding.
Q7. Who developed ENIAC? Practice
Correct answer: (D)
ENIAC (1946) was built by Eckert and Mauchly at the University of Pennsylvania.
ENIAC (1946) was built by Eckert and Mauchly at the University of Pennsylvania.
Q8. Which was the first commercial computer? Practice
Correct answer: (A)
UNIVAC I (1951) was the first commercially sold computer; it was used by the US Census Bureau.
UNIVAC I (1951) was the first commercially sold computer; it was used by the US Census Bureau.
Q9. Which is India's first indigenous supercomputer? Practice
Correct answer: (B)
PARAM 8000 (1991) was built by C-DAC Pune under Dr. Vijay Bhatkar. Pratyush and Mihir are later HPC systems.
PARAM 8000 (1991) was built by C-DAC Pune under Dr. Vijay Bhatkar. Pratyush and Mihir are later HPC systems.
Q10. The speed of a supercomputer is measured in: Practice
Correct answer: (C)
FLOPS = Floating Point Operations Per Second. MIPS is used for ordinary CPUs.
FLOPS = Floating Point Operations Per Second. MIPS is used for ordinary CPUs.
Q11. A computer that works on continuous quantities such as temperature and pressure is called: Practice
Correct answer: (D)
An analog computer measures continuously varying physical quantities; a digital computer works on 0/1.
An analog computer measures continuously varying physical quantities; a digital computer works on 0/1.
Q12. A machine used in a hospital ICU that has both analog and digital features is a: Practice
Correct answer: (A)
A hybrid computer processes analog measurements digitally.
A hybrid computer processes analog measurements digitally.
Q13. The ability of a computer to work continuously without tiring is called: Practice
Correct answer: (B)
Diligence = working without fatigue. Versatility = ability to do different kinds of tasks.
Diligence = working without fatigue. Versatility = ability to do different kinds of tasks.
Q14. Software permanently stored in a ROM chip, such as BIOS, is called: Practice
Correct answer: (C)
Firmware = software permanently written into hardware.
Firmware = software permanently written into hardware.
Q15. What is the full form of GIGO? Practice
Correct answer: (D)
If you give wrong input, the computer gives wrong output — that is GIGO.
If you give wrong input, the computer gives wrong output — that is GIGO.
Q16. Who coined the term "Artificial Intelligence"? Practice
Correct answer: (A)
John McCarthy coined the term at the 1956 Dartmouth conference; he is called the Father of AI.
John McCarthy coined the term at the 1956 Dartmouth conference; he is called the Father of AI.
Q17. The stored-program concept (program and data both in memory) is associated with: Practice
Correct answer: (B)
In the von Neumann architecture, program and data are kept in the same memory.
In the von Neumann architecture, program and data are kept in the same memory.
Q18. Who built the punched-card Tabulating Machine used in the 1890 US census? Practice
Correct answer: (C)
Herman Hollerith's company later became part of IBM.
Herman Hollerith's company later became part of IBM.
Q19. Who invented the Pascaline? Practice
Correct answer: (D)
Blaise Pascal built the Pascaline in 1642 — the first mechanical calculator for addition and subtraction.
Blaise Pascal built the Pascaline in 1642 — the first mechanical calculator for addition and subtraction.
Q20. Which is the correct descending order by size and capacity? Practice
Correct answer: (A)
Supercomputer is the most powerful, then mainframe, mini and micro (PC).
Supercomputer is the most powerful, then mainframe, mini and micro (PC).