UPSSSC exam questions in this area test inventors, inventions, year of development, and key mechanical/electronic milestones.
| Era / Machine | Year | Pioneer / Inventor | Key Features & Significance |
|---|---|---|---|
| Abacus | ~3000 BC | Ancient Mesopotamia / China | Earliest calculating device. Uses beads on parallel rods. |
| Napier’s Bones | 1617 | John Napier | Used marked ivory rods for multiplication/division. Introduced Logarithms. |
| Pascaline | 1642 | Blaise Pascal | First mechanical adding machine. Worked using gears, wheels, and dials. |
| Stepped Reckoner | 1673 | Gottfried Wilhelm Leibniz | First mechanical calculator that performed all 4 basic operations (+, -, ×, ÷). |
| Jacquard Loom | 1804 | Joseph Marie Jacquard | First machine to use punched cards to control woven pattern automation. |
| Difference Engine | 1822 | Charles Babbage | Automatic mechanical calculator designed to calculate polynomial functions. |
| Analytical Engine | 1837 | Charles Babbage | First general-purpose mechanical computer design. Included Input, Processing, Memory (Store), and Output. Charles Babbage is known as the "Father of Computers". |
| First Programmer | 1843 | Ada Lovelace | Wrote the first algorithm (for Babbage’s Analytical Engine) to calculate Bernoulli numbers. |
| Tabulating Machine | 1890 | Herman Hollerith | Electromechanical punched-card tabulator used for the 1890 US Census. Hollerith founded the company that became IBM in 1924. |
| Z1 / Z3 | 1936–1941 | Konrad Zuse | Z3 was the world's first working programmable, fully automatic digital computer. |
| ABC Computer | 1942 | John Atanasoff & Clifford Berry | First electronic digital calculating device (Atanasoff-Berry Computer). |
| Mark I | 1944 | Howard Aiken | First large-scale automatic electromechanical calculator built at Harvard with IBM. |
| ENIAC | 1946 | J. Presper Eckert & John Mauchly | First general-purpose fully electronic digital computer. Used 18,000+ vacuum tubes. |
| EDSAC | 1949 | Maurice Wilkes | First practical stored-program electronic computer. |
| EDVAC | 1949 | John von Neumann | Introduced the Stored-Program Architecture (data and instructions reside in the same memory). |
| UNIVAC I | 1951 | Eckert & Mauchly | First commercially produced electronic computer. |
| Gen | Switching Component | Primary Memory & Storage | Programming Language | Speed Unit | Key Examples |
|---|---|---|---|---|---|
| 1st Gen (1940–56) |
Vacuum Tubes | Magnetic Drums / Punch Cards | Machine Language (Binary: 0s and 1s) | Milliseconds (10-3 s) | ENIAC, EDVAC, UNIVAC, IBM 701, IBM 650 |
| 2nd Gen (1956–63) |
Transistors | Magnetic Core Memory / Tapes & Disks | Assembly Language, Early High-Level (FORTRAN, COBOL) | Microseconds (10-6 s) | IBM 1401, IBM 7094, CDC 1604, UNIVAC 1107 |
| 3rd Gen (1964–71) |
Integrated Circuits (ICs) | Magnetic Cores / Larger Disks | High-Level Languages (BASIC, PASCAL, C) | Nanoseconds (10-9 s) | IBM 360, PDP-8, Honeywell-6000, CDC 6600 |
| 4th Gen (1971–Now) |
Microprocessors (VLSI) | Semiconductor Memory (RAM/ROM) / Hard Disks, SSDs | High-Level Languages (C++, Java, Python, SQL) | Picoseconds (10-12 s) | Intel 4004 (1st Processor), IBM PC, Apple II |
| 5th Gen (Present+) |
ULSI & Artificial Intelligence | High-density Flash, Cloud, Quantum Memory | Natural Languages, AI Frameworks | Femtoseconds (10-15 s) | IBM Watson, Supercomputers, Quantum Computers |
Computers follow the IPO Model (Input → Process → Output) based on the Von Neumann Architecture.
Types: CRT, LCD, LED, OLED. Resolution is measured in total pixels, refresh rate in Hertz (Hz), and dot pitch measures pixel distance.
| Category | Types | Mechanism & Speed Metric |
|---|---|---|
| Impact Printers (Physical contact) |
Dot Matrix, Daisy Wheel, Drum/Chain Printers | Strikes inked ribbon onto paper. Loud and low quality. Speed measured in CPS (Characters Per Sec) or LPM (Lines Per Min). |
| Non-Impact Printers (No contact) |
Inkjet, Laser, Thermal Printers | Quiet & fast. Inkjet uses CMYK liquid ink. Laser uses Toner dry powder & laser beam. Speed in PPM (Pages Per Min). |
| Plotters | Flatbed & Drum Plotters | Prints large high-precision vector graphics, maps, and engineering blueprints using pens. |
| Abbreviation | Full Form |
|---|---|
| ENIAC | Electronic Numerical Integrator and Computer |
| EDVAC | Electronic Discrete Variable Automatic Computer |
| UNIVAC | Universal Automatic Computer |
| EDSAC | Electronic Delay Storage Automatic Calculator |
| MICR | Magnetic Ink Character Recognition |
| OCR / OMR | Optical Character Recognition / Optical Mark Recognition |
| BIOS / POST | Basic Input Output System / Power-On Self-Test |
| CMYK | Cyan, Magenta, Yellow, Key (Black) |
| VLSI / ULSI | Very Large Scale Integration / Ultra Large Scale Integration |
| DPI / PPM | Dots Per Inch / Pages Per Minute |
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