Publié le par aguh acheeh bih



History of the computer

History of the microprocessor







A – Keyboard

B – Mouse

C – Joysticks

D – Scanner

E – Microphone

F – Midi

G – Webcam


A – The monitor or the screen

B – Printers

C – Speakers

D – Graphic plotters

E – Micro film



A – Modem (modulator/demodulator)

B – Flash disk









A computer is an electronic machine that accepts data, processes it at very high speed according to specific instructions called program (Bruce Presley, Lawrenceville Press). The history of the computer explains how the computer was and how it is today. The need to perform large amounts of mathematical calculations and process large data has led to the evolution of the computer from one historical period to the other: prehistorical period, period of electronics, period of mini and micro, and period of network. With one period in possession of a more advanced machine, with improved technics   than the preceding one

In the 4th BC the Abacus a simple counting machine was invented in Babylon. It   was

used to register and predict notion of stars and planet.

John Napier Baron of Machiston (Scotland) introduced logs in 1614 which   allowed

 Multiplication and division to be reduced to addition and subtraction

Wilhelm Schickard in1623 builds the first mechanical calculator which could work six digits.

Blaise Pascal a French philosopher in 1642 builds a mechanical machine with a capacity of 8 digits but has problems carrying and its gears turn to jam.

 Charles Babbage in 1820-1821 conceives a Differential Massive Steam Powered Mechanical calculator designed to build astronomical tables.

Konrad Zuse, a German engineer in 1941 completes the General Programmable Calculator used for binary maths and Boolean logic in electronic calculations.

In 1943 ENIAC (Electronic Numeral Integrator and Computer) is developed by Ballistics Reseach in Maryland   to assist the preparation of fining tables is discovered

    UNIVAC (Universal Automatic Computer) is discovered in 1951 which could store 1200 digits in random access mercury delay lines.

In April 1964 the IBM is introduced which became the institutional mainframe   computer by 1980.

In 1965 an integrated circuit was introduced by Gordon Moore who predicted the number of components will double every year.

Doug Engelbart demonstrates in 1968 a word processor, an early hyper text system and a collaborative application which is now a common computer application. In 1982 the transmission control protocol and Internet protocol is established. In 1987 November network host breaks 10,000 .The Internet 1996  exposition is the worlds first fair on  internet.




The microprocessor  which was invented  in the early 70s has a  very  interesting history   full of fierce competition ,and advanced technology .The micro processor incorporates most or all the functions of the central processing unit, on a  single integrated  circuit using Binary Coded Decimals(BCD).INTEL,  came out with the first IBM and chose 8080 processor for the brains of the first cotmputer,since then INTEL remains the perceived leader of the micro processor though other contenders have developed their own  technology. The following chips are considered Dinosaurs of the computer world.

            From 1971-1977, 4004 was INTELS first micro processor. This break through intervention powered the busicom calculator and paved the way for embedding intelligence in computer. The 8008 was twice as powerful as the 4004.The 8080 became the brains of the first personal computer.1978 saw the advent of the 8086.It was a 16 bit processor, the chip contained 29,000 transistors and 20 address lines that gave it the ability to contain 1MB of RAM .In 1979 came INTEL 8088,it was identical to 8080  with only difference being the way it handled the address lines .. In 1982 INTELs 286 originally known as 80286 came. It was a microprocessor of 16 bit with 134000 transistors capable of addressing up to16 MB of  RAM. It was the first real processor to introduce the concept of protected mode, this is the ability to do multi task, having different program run separately but at same time. It ran 8, 10,12.5 MHz but later 20MHZ.from 1985-1990 INTEL 386  It was a 32 bit with  275000 transistors. It was the first chip to do instructional pipelining which allowed the processor start working on the first instruction before the previous is even completed

1992 saw INTEL   486DX which provided a coloured computer for the first time and could do desk top publishing at a significant speed. IT was the first to offer a built in math coprocessor with speed up computing. 1993 saw   the arrival of INTEL Pentium processor.

 This processor allowed computers to more easily incorporate real world data such as speech, hand writing, photographic images

1995 NTEL Pentium 2 processor came with 7.5 million transistors; this   technology was designed specifically to process video audio and graphics data efficiently. It also incorporated a high speed cache memory chip. With this chip users could capture, edit and share digital photos with friends family through the internet.  1998-2000 saw the advent of Pentium 3 and 4 which accelerated innovations specifically designed for work stations, featuring 70 instructions increasing performance of advanced imaging. Later in 2001-2003 came the INTEL Itanium and Pentium M processors





A computer is an electronic machine that accepts data, processes it at very high speed according to specific instructions called program (Bruce Presley, Lawrenceville Press).Input and output devices are material components of the computer which assures the exchange of information and communication between the computer and the external world (environment). These input and output play a capital role in the functioning of a computer. Once more the problem we are faced with is to know the particularity, singularity of these components which permit us to communicate with the computer. To answer this question we are going to structure our analysis into three essential parts taking into consideration the definition, presentation and functioning of input, output, input/output (bidirectional).



Input devices are those devices which permit us to enter data, command, instructions and programs into the computer which are processed by the central processing unit.


A – Keyboard

It is considered as the principal input device and permits to enter text information in the form of the figures or symbols. The keyboard can also be used to type the commands directing the computer to perform certain actions. There are three types of the keyboard, the German, the English and the French that is Qwertzy, Qwerty, Azerty respectively. It contains 120 buttons and it is divided into five parts: numeral part, alphabetic, functional, key control and displacement keys.


B – A mouse

The mouse is a pointing device which permits to select command and displace the cursor. It is moved on the surface of a desk or on a mouse pad. It is composed of two parts the right which is used to for clicking the program you want to effectuate and the left part which is to click, double click, and select a portion of text to be treated. In most mouses, we find a button between the two parts which enable the text to go up and down. There are five big families of mouses: mechanical mouse, opto-mechanical mouse, optical mouse, wheel mouse and wireless mouse.


C – Joysticks

Are also another kind of pointing device of a personal computer.  They are generally used for playing games and not for controlling the on screen cursor in productivity software.

D – Scanner

A scanner is an input device that is used to scan images and text them into the computer.  It also permits the typing of data captage and filming images by digitizing it producing an image made of tiny pixels of different brightness and colors, representing them numerically and sent to the computer. There are two types of scanners flat bed and hand held scanner.


E – Microphone

A microphone can be attached to the computer to record sounds (usually through a sound card or circuitry, built into the mother board. The sound is digitized, turned into numbers that represent the original analog sound waves and stored in the computer to later processing and play back.


F – Midi (Musical Instrument Digital interface)

Is a system designed to transmit information between electronic musical instruments. A musical keyboard can be attached to a computer and allow a performer to play music that is captured by the computer system as a sequence of note with associate timing (instead of recording digitized sound waves).


G – Webcam

Is an input device which is a low resolution video camera used provided visual input that can be easily be transferred over the internet.



Out-put devices permit us to receive, see and understand the results of processed data manipulated by the computer.

A – The monitor or the screen

Is an output device which permits the computer to paste data already processed to enable the user visualize and to understand its content. It is composed of a graphic card with characteristics permitting the regulation of images. Its dimension is expressed in inches, (an inch equal 2, 54 cm). There are screens of 15, 17, 19 and 21 inches which correspond to the diagonal of the screen. There are mainly two types of monitors which are traditional or ordinary monitors cathode Ray Tube (CRT) and the flat panel display (LCD) Liquid Crystal Display.


B – Printers

It is an output device which permits the sending out of treated texts and images by the computer on a paper that is sending out treated information in the form of hard copies. There are two types of printers: impact printers (line printers and character printers) and non impact printers (inkjet printers, laser printers and thermal printers).


C – Speakers

It is an output device which emits sounds and controls it at the start of the computer.


D – Graphic plotters

It is a device that produces output on paper that is hard copies, like printers do. Instead of producing images and text using print, head print, ribbons or lasers they use paint. Plotters produce very high quality diagrams at a very high speed and therefore perfect for engineering application.


E – Micro film

This can be liken to films and photograph the frame of film is much smaller than a photograph produced from it. Micro film is used for storing.



They are used to inter information into the computer and also to send them out. It permits to transfer information in a bi-directional manner.


A-    Modem(modulator/demodulator)

It is a device used to transfer information between many computers through telephone lines. The modem converts analogically binary information provided by the computer. It sends this new code into the phone line. This is why we say it is an analogical and numeric convertor. It is characterized by its speed expressed in seconds.

B – Rewritable CD or DVD ROM

They permit to record data into the computer and also to read recorded information through the screen.


C – Flash disk (Universal Serial Bus)

Universal Serial Bus permits to enter texts, images and sounds into the computer and also permit taking of information from the computer through internet to be seen.





To conclude we can say input and output devices are indispensible components of a personal computer. This is because they served as intermediary between the user and the machine in the process of communication as they are at the beginning and end of all processes, instructions executed in the machine. If the user wants to realize any tasks for input devices texts processing (keyboard) pointing devices (joysticks, game pad, game controller), image video input devices (images, scanner, webcam projector), audio input devices (microphone, Mic, disks reader). For output, image video output (printer, monitor), audio output (speakers, head set). Thus without these devices, no operation can be effectuated.





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