(Very brief) What is computer? A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations.

That is, electronic computers (and the earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions … Imagine this job where hour after hour, day after day, you were to do nothing but compute multiplications? Boredom would lead to carelessness and mistakes. Speed was an issue too… Therefore, inventors have been searching for hundreds of years for a way to mechanize this task.

The abacus was early used for arithmetic tasks. What we now call the Roman abacus was used in Babylonia as early as 2400 BC! An abacus is a manual aid to calculating that consists of beads or disks that can be moved up and down on a series of sticks or strings within a usually wooden frame. The abacus itself doesn't calculate; it's simply a device for helping a human being to calculate by remembering what has been counted.

He made drawings of gear-driven calculating machines but apparently never built any. A Leonardo da Vinci drawing showing gears arranged for computing …

In 1642 Blaise Pascal, at age 19, invented the Pascaline as an aid for his father who was a tax collector. Pascal built 50 of this gear-driven one- function calculator (it could only add) but couldn't sell many because of their exorbitant cost and because they really weren't that accurate (at that time it was not possible to fabricate gears with the required precision). Up until the present age when car dashboards went digital, the odometer portion of a car's speedometer used the very same mechanism as the Pascaline to increment the next wheel after each full revolution of the prior wheel. Pascal was a child prodigy. At the age of 12, he was discovered doing his version of Euclid's thirty-second proposition on the kitchen floor.. Pascal went on to invent probability theory, the hydraulic press, and the syringe

In 1617 an eccentric (some say mad) Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. Napier also invented an alternative to tables, where the logarithm values were carved on ivory sticks which are now called Napier's Bones. Napier's invention led directly to the slide rule, first built in England in 1632 and still in use in the 1960's by the NASA engineers of the Mercury, Gemini, and Apollo programs which landed men on the moon.

Punched card system of a music machine, also referred to as Book music In 1801, Frenchman Joseph-Marie Jacquard developed a loom in which the pattern being woven was controlled by punched cards. The series of cards could be changed without changing the mechanical design of the loom. This was a landmark achievement in programmability. Descendants of these punched cards have been in use ever since (remember the "hanging chad" from the Florida presidential ballots of the year 2000?).

By selecting particular cards for Jacquard's loom you defined the woven pattern Jacquard's technology was a real boon to mill owners, but put many loom operators out of work. Angry mobs smashed Jacquard looms and once attacked Jacquard himself. History is full of examples of labor unrest following technological innovation yet most studies show that, overall, technology has actually increased the number of jobs.

Trial model of a part of the Analytical Engine, built by Babbage, as displayed at the Science Museum (London). In 1833, Charles Babbage moved on from developing his difference engine (for navigational calculations) to a general purpose design, the Analytical Engine, which drew directly on Jacquard's punched cards for its program storage. Ada Lovelace, Lord Byron's daughter, translated and added notes to the "Sketch of the Analytical Engine" by Federico Luigi, Conte Menabrea. This appears to be the first published description of programming!

Augusta Ada King, Countess of Lovelace (1815 – 1852), born Augusta Ada Byron and commonly known as Ada Lovelace, was an English mathematician and writer chiefly known for her work on Charles Babbage's early mechanical computer, the Analytical Engine. Her notes on the engine include what is recognized as the first algorithm intended to be carried out by a machine. Because of this, she is often described as the world's first computer programmer. Ada described her approach as "poetical science" and herself as an "Analyst (& Metaphysician)". Between 1842 and 1843, she translated an article by Italian military engineer Luigi Menabrea on the Analytical Engine, which she supplemented with an elaborate set of notes of her own, simply called the Notes. Notes contain what many consider to be the first computer program(algorithm designed to be carried out by a machine). Lovelace's notes are important in the early history of computers. She also developed a vision on the capability of computers to go beyond mere calculating or number-crunching while others, including Babbage himself, focused only on those capabilities. Ada's mind-set of "poetical science" led her to ask basic questions about the Analytical Engine (as shown in her notes) examining how individuals and society relate to technology as a collaborative tool.

In Japan, Ryōichi Yazu patented a mechanical calculator called the Yazu Arithmometer in It consisted of a single cylinder and 22 gears, and employed the mixed base-2 and base-5 number system familiar to users of the soroban (Japanese abacus). Carry and end of calculation were determined automatically. More than 200 units were sold, mainly to government agencies such as the Ministry of War and agricultural experiment stations.

A scene from the U.S. Social Security Administration (SSA)'s early accounting operations in Baltimore circa The issuing of Social Security numbers and the creation of earnings records on all Americans covered by Social Security was the largest bookkeeping operation in the history of the world. President Franklin D. Roosevelt A few of the hundreds of keypunch operators SSA employed throughout the late 1930s and into the 1950s

Cambridge differential analyzer, 1938.

Friden paper tape punch. Punched tape programs would be much longer than the short fragment of yellow paper tape shown, 1937.

Left hand holding my Curta Type I Calculator (Sn ), which I purchased for $10.00 in Santa Cruz, CA in 1948.

Half-inch (12.7 mm) magnetic tape, originally written with 7 tracks and later 9- tracks. Alan Turing's 1936 paper proved enormously influential in computing and computer science in two ways:  Its main purpose was to prove that there were that could not be solved by any sequential process.  In doing so, Turing provided a definition of a universal computer which executes a program stored on tape. This construct came to be called a Turing machine…

In 1952, Turing was arrested and tried for homosexuality, then a criminal offence. To avoid prison, he accepted injections of estrogen for a year… He committed suicide on 7 June, “bombe” 23 June 1912 – 7 June 1954) was a British mathematician, logician, cryptanalyst, computer scientist and philosopher. He was highly influential in the development of computer science, providing a formalization of the concepts of "algorithm" and "computation" with the Turing machine, which can be considered a model of a general purpose computer. Turing is widely considered as the "Father” of Theoretical Computer Science and Artificial Intelligence”. The Queen granted him a posthumous pardon on 24 December 2013.pardon mix/wp/2014/06/09/a-computer-just-passed-the-turing-test- in-landmark-trial/ A computer just passed the Turing Test in landmark trial! Can machines think?

Working in isolation in Germany, Konrad Zuse started construction in 1936 of his first Z-series calculators featuring memory and (initially limited) programmability. Zuse's purely mechanical, but already binary Z1, finished in 1938, never worked reliably due to problems with the precision of parts.

Colossus was used to break German ciphers during World War II. Alan Turing's use of probability in cryptanalysis contributed to its design.

In the days before Intel, Apple and Google, computing was a much more traditional affair. We're talking levers, gears, and other mechanisms that could all automate counting in some way or other. Russian scientist Vladimir Lukyanov, however, built one that ran on water. Built in 1936, it was the world's first computer for solving partial differential equations (pain to do by hand). To solve the differential equations, Lukyanov fiddled around with a series of interconnected, water-filled glass tubes. The levels in certain tubes gave the answers, while adjusting taps and plugs changed variables. The device was actually used to solve problems related to cracks in concrete, but it inspired other devices and applications, which saw the same technology being used in fields such as geology, thermal physics, metallurgy and rocket engineering. Not bad for some fancy plumbing!

In 1939, John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed the Atanasoff–Berry Computer (ABC), The Atanasoff- Berry Computer was the world's first electronic digital computer. The design used over 300 vacuum tubes and employed capacitors fixed in a mechanically rotating drum for memory. Though the ABC machine was not programmable, it was the first to use electronic tubes in an adder.

ENIAC performed ballistics trajectory calculations with 160 kW of power It construction lasted from 1943 to full operation at the end of The machine was huge, weighing 30 tons, using 200 kilowatts of electric power and contained over 18,000 vacuum tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors. One of the major engineering feats was to minimize tube burnout, which was a common problem at that time. The machine was in almost constant use for the next ten years.

IBM 650 front panel This RAMAC DASDis being restored at the Computer History Museum Magnetic core memory. Each core is one bit. Parts from early computers: ENIAC EDVAC, ORDVAC, and BRLESC I

Punch card Tabulator, 1961

Intel 8742 eight-bit microcontroller IC The integrated circuit in the image on the right, for example, an Intel 8742, is an 8-bit microcontroller that includes a CPU running at 12 MHz, 128 bytes of RAM, 2048 bytes of EPROM, and I/O in the same chip.

Computer History Year/Enter Computer History Inventors/Inventions Computer History Description of Event 1936Konrad Zuse - Z1 ComputerFirst freely programmable computer John Atanasoff & Clifford Berry ABC Computer Who was first in the computing biz is not always as easy as ABC Howard Aiken & Grace Hopper Harvard Mark I Computer The Harvard Mark 1 computer John Presper Eckert & John W. Mauchly ENIAC 1 Computer 20,000 vacuum tubes later...

1948 Frederic Williams & Tom Kilburn Manchester Baby Computer & The Williams Tube Baby and the Williams Tube turn on the memories. 1947/48 John Bardeen, Walter Brattain & Wiliam Shockley The Transistor No, a transistor is not a computer, but this invention greatly affected the history of computers John Presper Eckert & John W. Mauchly UNIVAC Computer First commercial computer & able to pick presidential winners International Business Machines IBM 701 EDPM Computer IBM enters into 'The History of Computers' John Backus & IBM FORTRAN Computer Programming Language The first successful high level programming language.

1955 (In Use 1959) Stanford Research Institute, Bank of America, and General Electric ERMA and MICR The first bank industry computer - also MICR (magnetic ink character recognition) for reading checks Jack Kilby & Robert Noyce The Integrated Circuit Otherwise known as 'The Chip' 1962 Steve Russell & MIT Spacewar Computer Game The first computer game invented Douglas Engelbart Computer Mouse & Windows Nicknamed the mouse because the tail came out the end ARPAnetThe original Internet.

1970Intel 1103 Computer Memory The world's first available dynamic RAM chip Faggin, Hoff & Mazor Intel 4004 Computer Microprocessor The first microprocessor Alan Shugart &IBM The "Floppy" Disk Nicknamed the "Floppy" for its flexibility Robert Metcalfe & Xerox The Ethernet Computer Networking Networking. 1974/75 Scelbi & Mark-8 Altair & IBM 5100 Computers The first consumer computers.

1976/77 Apple I, II & TRS-80 & Commodore Pet Computers More first consumer computers Dan Bricklin & Bob Frankston VisiCalc Spreadsheet Software Any product that pays for itself in two weeks is a surefire winner Seymour Rubenstein & Rob Barnaby WordStar Software Word Processors IBM The IBM PC - Home Computer From an "Acorn" grows a personal computer revolution 1981 Microsoft MS-DOS Computer Operating System From "Quick And Dirty" comes the operating system of the century. 1983Apple Lisa Computer The first home computer with a GUI, graphical user interface. 1984Apple Macintosh Computer The more affordable home computer with a GUI. 1985Microsoft Windows Microsoft begins the friendly war with Apple.