Magnitic Memory

 

Term	Type of Storage	Era / Generation	How It Works	Purpose / Use	Example / Notes
Magnetic Drum	Primary / Secondary memory	1950s–1960s (First/Second Gen)	Cylinder coated with magnetic material rotates; read/write heads access data	Early main memory for programs and data	IBM 650 used magnetic drum memory; access was sequential (slow)
Magnetic Tape	Sequential secondary storage	1950s–present	Data stored on long magnetic ribbon wound on reels; read/write by tape drive heads	Backup, archiving, and large data storage	Still used in banks, data centers for backups
Magnetic Disk (Hard Disk / HDD)	Random access secondary storage	1956–present	Data stored on spinning metal/platter coated with magnetic material; read/write heads move over surface	Main storage for files, programs	IBM 305 RAMAC (1956) first commercial HDD
Magnetic Bubble Memory	Non-volatile memory	1970s–1980s (Experimental / Niche)	Uses tiny magnetic domains (“bubbles”) in a thin film to store data; manipulated with magnetic fields	Replaces some RAM / ROM for rugged devices	Non-volatile, no moving parts, slow but reliable; used in aerospace and industrial applications
Core Memory (Magnetic Core)	Primary memory	1950s–1970s (First/Second Gen)	Tiny magnetic rings (cores) threaded with wires; direction of magnetization stores 1 or 0	Main memory (RAM) for computers	IBM 704, PDP series used core memory; very durable
Floppy Disk	Secondary storage	1970s–1990s	Thin magnetic disk inside protective casing; read/write via floppy drive	Portable data storage	5.25” and 3.5” floppies, slowly replaced by optical and flash storage
Zip Disk / Magneto-Optical Disk	Secondary storage	1990s	Magnetic + optical technology to read/write data	Portable storage, higher capacity than floppies	Used in professional graphics / data storage before USB drives

History Of Computer

Computer	Full Form	Year	Generation / Type	Inventor / Organization	Main Purpose	Main Component
Z1	(Model name)	1938	Mechanical / Pre-electronic	Konrad Zuse	First programmable mechanical computer	Mechanical parts
Z2	(Model name)	1939	Electromechanical	Konrad Zuse	Improved programmable calculator	Relays
Z3	(Model name)	1941	Electromechanical	Konrad Zuse	First working programmable automatic computer	Relays
Atanasoff–Berry Computer	ABC	1939–1942	Electronic Digital (Experimental)	John Vincent Atanasoff & Clifford Berry	Solve simultaneous linear equations	Vacuum tubes
Colossus	(Not an acronym)	1943	Electronic Digital	Tommy Flowers	WWII code breaking	Vacuum tubes
Harvard Mark I	Automatic Sequence Controlled Calculator	1944	Electromechanical	Howard Aiken with IBM	Scientific calculations	Relays
ENIAC	Electronic Numerical Integrator and Computer	1945	First Generation	John Mauchly & J. Presper Eckert	Military trajectory calculations	Vacuum tubes
Manchester Baby	Small Scale Experimental Machine	1948	First Generation	Frederic C. Williams & Tom Kilburn	First stored-program execution	Vacuum tubes
EDVAC	Electronic Discrete Variable Automatic Computer	1949	First Generation	John Mauchly & J. Presper Eckert	Stored-program architecture	Vacuum tubes
EDSAC	Electronic Delay Storage Automatic Calculator	1949	First Generation	Maurice Wilkes	Scientific research	Vacuum tubes
UNIVAC I	Universal Automatic Computer	1951	First Generation	J. Presper Eckert & John Mauchly	Commercial data processing	Vacuum tubes
LEO I	Lyons Electronic Office	1951	First Generation	J. Lyons and Co.	Business management	Vacuum tubes
IBM 701	(Model number)	1952	First Generation	IBM	Scientific computing	Vacuum tubes
IBM 650	(Model number)	1954	First Generation	IBM	Business and education	Vacuum tubes

 

Punch Card

 

1️⃣ What is a Punch Card?

A punch card is a stiff paper card with holes punched in specific positions to represent data or instructions. Early computers and machines read these holes to process information.

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2️⃣ Origin of Punch Cards

The idea of punch cards started in 1801 with the invention of the Joseph Marie Jacquard loom.

• He created the Jacquard Loom.

• The loom used punched cards to control weaving patterns automatically.

• Each card told the loom which threads to lift or lower.

📌 This was the first time machines were controlled by coded instructions.

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3️⃣ Use in Data Processing

Later, punch cards were used for data processing by Herman Hollerith.

• In 1890, he invented the Hollerith Tabulating Machine.

• It used punch cards to store and count census data.

• The 1890 U.S. Census was completed much faster using this machine.

📌 Hollerith’s company later became IBM.

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4️⃣ Punch Cards in Early Computers

Punch cards became very important in early computers (1950–1970).

They were used to:

• Input programs

• Store data

• Control computer instructions

Programmers would write code and punch holes in cards, then feed them into computers.

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5️⃣ Structure of a Punch Card

A standard punch card had:

• 80 columns

• Each column represented one character

• Holes represented binary data

This format was called the IBM 80-column card.

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6️⃣ Decline of Punch Cards

Punch cards slowly disappeared because:

• Magnetic tapes were faster

• Disk storage was easier

• Computers became more interactive

By the 1980s, punch cards were mostly obsolete.

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7️⃣ Importance in Computer History

Punch cards were important because they:

• Introduced the idea of programming machines

• Allowed data storage and automated processing

Calcuating Devices

 

S.N	Calculating Device	Inventor	Year	Purpose
1	Abacus	Unknown (Ancient China)	~3000 BC	First device used for counting and basic arithmetic
2	Napier’s Bones	John Napier	1617	Used for multiplication and division
3	Slide Rule	William Oughtred	1622	Used for multiplication, division, roots, logarithms
4	Pascaline	Blaise Pascal	1642	Could perform addition and subtraction
5	Stepped Reckoner	Gottfried Wilhelm Leibniz	1673	Performed addition, subtraction, multiplication, division
6	Difference Engine	Charles Babbage	1822	Used to calculate mathematical tables
7	Analytical Engine	Charles Babbage	1837	First concept of a programmable computer
8	Tabulating Machine	Herman Hollerith	1890	Used to process U.S. census data

People and Their Invension.

S.N	Person	Brief History / Contribution
1	John Napier	Invented Napier’s Bones (1617) to simplify multiplication and division using rods. Also introduced logarithms.
2	William Oughtred	Invented the Slide Rule (1622) which engineers used for calculations for many years.
3	Blaise Pascal	Invented Pascaline (1642), the first mechanical calculator that could perform addition and subtraction.
4	Gottfried Wilhelm Leibniz	Built the Stepped Reckoner (1673) which could perform multiplication and division automatically.
5	Joseph Marie Jacquard	Invented the Jacquard Loom (1801) that used punched cards to control weaving patterns. This idea later influenced computer programming.
6	Charles Babbage	Known as the Father of the Computer. Designed the Difference Engine and Analytical Engine, the first concept of a programmable computer.
7	Ada Lovelace	Wrote the first computer algorithm for Babbage’s Analytical Engine. She is known as the first computer programmer.
8	Herman Hollerith	Invented the Tabulating Machine (1890) using punched cards to process census data faster. His company later became IBM.
9	Howard Aiken	Developed the Harvard Mark I computer in 1944.
10	John von Neumann	Proposed the stored-program concept, which is the basic architecture of modern computers.