History of Computers: The Abacus

History of Computers

• The abacus is one of the earliest known tools for calculation, originating several thousand years ago.
• It is a simple counting device used to perform arithmetic operations like addition, subtraction, multiplication, and division.

Origins and Structure of the Abacus

• The exact origins of the abacus are unclear.
• Evidence suggests that it was used in ancient civilizations, like Mesopotamia, Egypt, Greece, Rome, China, and Japan.
• The word "abacus" derives from the Greek word "abax," meaning "counting board" or "calculating table."
• The abacus typically consists of a rectangular frame with rods or wires strung with beads.
• The frame is divided into two sections by a horizontal bar.
• The upper section (Heaven) usually contains one or two beads per rod.
• The lower section (Earth) contains four or five beads per rod.

Types of Abacuses

• Chinese Abacus (Suanpan) typically has two beads in the upper section and five in the lower section.
• Japanese Abacus (Soroban) generally has one bead in the upper section and four in the lower section.
• Russian Abacus (Schoty) consists of ten beads per rod and does not have a horizontal bar dividing the frame.

Blaise Pascal's Pascaline

• Invented by Blaise Pascal in 1642, the Pascaline is one of the earliest mechanical calculators.
• It was designed to help Pascal's father, a tax collector, with arithmetic calculations. It is a rectangular box with a series of rotating dials on its face with each dial corresponding to a digit in a number, from units to tens, hundreds, and so on.
• Each dial is connected to a series of gears that rotate when the dial is turned.
• When one dial completes a full rotation (from 0 to 9), it automatically advances the next dial by one unit, enabling the addition of multi-digit numbers.
• Users input numbers by turning the dials to the desired digits.
• The machine can perform addition directly and subtraction.

Gottfried Wilhelm Leibniz's Stepped Reckoner

• Invented by Gottfried Wilhelm Leibniz in 1672, the Stepped Reckoner expanded on the ideas of earlier mechanical calculators like the Pascaline.
• It uses a series of cylindrical gears called "stepped drums," with each drum having nine teeth of varying lengths, corresponding to the digits 0 through 9.
• The movement of the gears and drums allows for the mechanical addition, subtraction, multiplication, and division of numbers.
• The stepped drums engage with a movable carriage, which shifts to perform these operations.
• Users set numbers on the machine's dials, and through a series of manual cranks and lever movements, the machine performs the desired arithmetic operations.
• The results are displayed on a series of windows or dials on the machine.

Charles Babbage's Analytical Engine

• Conceptualized by Charles Babbage in the 1830s, the Analytical Engine is considered one of the first designs for a general-purpose mechanical computer.
• The Analytical Engine was designed to perform any calculation or data processing task, given the appropriate instructions and data.

Structure and Components of the Analytical Engine

• The Store was designed to hold data and intermediate results and consisted of thousands of mechanical wheels and gears capable of storing large numbers.
• The Mill functioned as the central processing unit (CPU) of the machine and performed arithmetic operations (addition, subtraction, multiplication, and division) on data fetched from the Store.
• The Engine used punched cards to input instructions and data.
• Operation cards told the Engine what operations to perform, and variable cards specified the data to be used; this allowed the Engine to execute a sequence of instructions, or a program.
• The results of computations were to be printed on paper or punched onto cards for further use, akin to a printer or display in modern computers.

Ada Lovelace's Contributions

• Ada Lovelace, born Augusta Ada Byron in 1815, is celebrated as the first computer programmer.
• Her work with Charles Babbage on the Analytical Engine laid the groundwork for computer programming.

Menabrea's Memoir

• In 1842, Lovelace translated an Italian article by Luigi Federico Menabrea about Babbage's Analytical Engine, adding extensive commentary on the workings and potential of the Analytical Engine upon Babbage's request.
• Lovelace's notes ended up being three times longer than the original article.

First Algorithm

• Lovelace described an algorithm to compute Bernoulli numbers using the Analytical Engine, which is regarded as the first algorithm specifically tailored for implementation on a machine.
• Her method involved a detailed sequence of operations, demonstrating how the machine could be programmed to perform complex calculations autonomously.

Concept of a General-Purpose Computer

• Lovelace recognized that the Analytical Engine had applications beyond pure calculation.
• She understood that the machine could manipulate symbols and numbers to solve a variety of problems.
• She foresaw the potential for the machine to be used in areas such as composing music, generating graphics, and more, given the appropriate algorithms and data.

Capabilities of the Analytical Engine

• Lovelace introduced the idea that the Analytical Engine could act upon anything that could be expressed in symbolic form, such as logic and algebra, anticipating modern computing's data processing capabilities.
• She emphasized the distinction between the machine's ability to follow instructions (execute algorithms) and human creativity to create these instructions.

Collaboration with Babbage

• Lovelace worked closely with Babbage, gaining a deep understanding of his designs and providing insights that advanced his work.
• Her articulation of the Analytical Engine's potential and functionality helped communicate its significance to a broader audience.

The Birth of Modern Computers

• The shift from mechanical and electromechanical devices to fully electronic computers represented a revolutionary advancement in computing technology.
• This transition was driven by the need for faster and more efficient machines, particularly during World War II, which required rapid and reliable computations for various military applications.

Atanasoff-Berry Computer (ABC)

• Developed by John Atanasoff and Clifford Berry, completed in 1942.
• The ABC used binary representation and electronic switching elements (vacuum tubes) to perform calculations & designed to solve linear algebraic equations.
• It introduced key concepts like binary arithmetic and electronic logic circuits, used in later computers.

Colossus

• Developed by British codebreakers, led by Tommy Flowers completed in 1943.
• Colossus was the world's first programmable digital electronic computer.
• It was used by British cryptographers at Bletchley Park to break the Lorenz cipher used by the German military using thousands of vacuum tubes and performing complex cryptographic analyses much faster than human operators.

Electronic Numerical Integrator and Computer (ENIAC)

• Developed by John Presper Eckert and John Mauchly at the University of Pennsylvania, completed in 1945.
• ENIAC was the first general-purpose electronic digital computer using over 17,000 vacuum tubes and capable of performing a wide range of computations at unprecedented speeds.
• Initially designed for calculating artillery firing tables for the U.S. Army, ENIAC could be reprogrammed to solve different problems.

Electronic Discrete Variable Automatic Computer

• Developed by John von Neumann and the team at the University of Pennsylvania and completed in 1951.
• EDVAC was one of the first computers to implement the stored.

The Development of the Z3

• Konrad Zuse is credited with creating the Z3, the world's first programmable, fully automatic digital computer, which was completed in 1941.
• Zuse chose to implement binary arithmetic in the Z3.
• Binary arithmetic is simpler and more efficient for electronic computation, and it remains the foundation of all modern computers.