CLASS

4TH

ABACUS

LOGARITHMS

ALLOWED MULTIPLICATION TO BE DONE BY REPEATED ADDITION

PASCALINETHEN CAME GEAR DRIVEN ONE FUNCTION

CALCULATOR(IT COULD ONLY ADD)AND LATER FOUR FUNCTION ONE

A GREAT TECHNOLOGICAL INNOVATION WAS THE INTRODUCTION OF BINARY SYSTEM BY LEIBNIZ WHICH IS FUNDAMENTAL TO THE USE OF MODERN COMPUTERS

1801 the Frenchman Joseph Marie Jacquard invented a power loom that could base its weave (and hence the design on the fabric) upon a pattern automatically read from punched wooden cards, held together in a long row by rope

By 1822 the English mathematician Charles Babbage was proposing a steam driven calculating machine the size of a room, which he called the Difference Engine. This machine would be able to compute tables of numbers, such as logarithm

Babbage realized that punched paper could be employed as a storage mechanism, holding computed numbers for future reference.

Babbage saw that the pattern of holes could be used to represent an abstract idea such as a problem statement or the raw data required for that problem's solution.

Babbage called the two main parts of his Analytic Engine the "Store" and the "Mill

. The Store was where numbers were held and the Mill was where they were "woven" into new results. In a modern computer these same parts are called the memory unit and the central processing unit (CPU).

The Analytic Engine also had a key function that distinguishes computers from calculators: the conditional statement. A conditional statement allows a program to achieve different results each time it is run

The conditional statement also allows a program to react to the results of its own calculations

Charles Babbage took the help of Ada Byron to begin fashioning programs for his Analytic Machine and so she became the first ever computer programmer in the world.

The next breakthrough occurred in AMERICA when the 1880 census was to be carried out.This required quick computing.

Herman Hollerith, proposed and then successfully adopted Jacquard's punched cards for the purpose of computation

Hollerith's invention, known as the Hollerith desk, consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count (using Pascal's mechanism which we still see in car odometers), and a large wall of dial indicators (a car speedometer is a dial indicator) to display the results of the count.

Hollerith had the insight to convert punched cards to what is today called a read/write technology.

Two types of computer punch cards

The Harvard Mark I computer in 1944 was the first programmable digital computer made in the U.S.

Mark I was constructed out of switches, relays, rotating shafts, and clutches. The machine weighed 5 tons, incorporated 500 miles of wire, was 8 feet tall and 51 feet long, and had a 50 ft rotating shaft running its length, turned by a 5 horsepower electric motor.

The principal designer of the Mark I was Howard Aiken

Here's a close-up of one of the Mark I's four paper tape readers. A paper tape was an improvement over a box of punched cards

Grace Hopper One of the primary programmers for the Mark I

found the first computer "bug":

Hopper is credited with coining the word "debugging" to describe the work to eliminate program faults

In 1953 Grace Hopper invented the first high-level language, "Flow-matic". This language eventually became COBOL

A high-level language is designed to be more understandable by humans than is the binary language understood by the computing machinery

A high-level language is worthless without a program -- known as a compiler -- to translate it into the binary language of the computer and hence Grace Hopper also constructed the world's first compiler

The Mark I operated on numbers that were 23 digits wide. It could add or subtract two of these numbers in three-tenths of a second, multiply them in four seconds, and divide them in ten seconds. Forty-five years later computers could perform an addition in a billionth of a second! Even though the Mark I had three quarters of a million components, it could only store 72 numbers! Today, home computers can store 30 million numbers in RAM and another 10 billion numbers on their hard disk.

By 1959 ,there came the micro-electronics revolution in which IBM introduced the IBM Stretch.

to be bested by a home computer of 1976 such as this Apple I which sold for only $600:

The Apple 1 which was sold as a do-it-yourself kit (without the lovely case seen here)

The title of forefather of today's all-electronic digital computers is usually awarded to ENIAC, which stood for Electronic Numerical Integrator and Calculator.

ENIAC was built at the University of Pennsylvania between 1943 and 1945 by two professors, John Mauchly and the 24 year old J. Presper Eckert

ENIAC filled a 20 by 40 foot room, weighed 30 tons, and used more than 18,000 vacuum tubes. Like the Mark I, ENIAC employed paper card readers obtained from IBM

Eckert and Mauchly's next teamed up with the mathematician John von Neumann to design EDVAC, which pioneered the stored program.

By the end of the 1950's Eckert and Mauchly left the University of Pennsylvania &

decided to set up their own company

Their first product was the famous UNIVAC computer, the first commercial (that is, mass produced) computer.

By 1955 IBM was selling more computers than UNIVAC and by the 1960's the group of eight companies selling computers was known as "IBM and the seven dwarfs".

In1982,IBM hired Microsoft to provide the software for their Personal Computer

Intel was the first to succeed in cramming the entire computer on a single chip.

This transformation was a result of the invention of the microprocessor. A microprocessor (uP) is a computer that is fabricated on an integrated circuit (IC)

A Harvard freshman by the name of Bill Gates decided to drop out of college so he could concentrate all his time writing programs for this computer. This early experienced put Bill Gates in the right place at the right time once IBM decided to standardize on the Intel microprocessors for their line of PCs in 1981. The Intel Pentium 4 used in today's PCs is still compatible with the Intel 8088 used in IBM's first PC.