THE FIRST GENNERATION (1940-1956)
First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.
This generation used vacuum tubes with two notable computers being the UNIVAC and the ENIAC
Second Generation (1956-1963) Transistors
This Generation replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.
The Third generation (1964-1971)
The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.
The fourth Genneration (1971-present)
The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.
In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.
As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.
Fifth Generation (Present and Beyond) Artificial Intelligence
Alan Turing was born on 23 June, 1912, in London. His father was in the Indian Civil Service and Turing's parents lived in India until his father's retirement in 1926. Turing and his brother stayed with friends and relatives in England. Turing studied mathematics at Cambridge University, and subsequently taught there, working in the burgeoning world of quantum mechanics. It was at Cambridge that he developed the proof which states that automatic computation cannot solve all mathematical problems. This concept, also known as the Turing machine, is considered the basis for the modern theory of computation.
In 1936, Turing went to Princeton University in America, returning to England in 1938. He began to work secretly part-time for the British cryptanalytic department, the Government Code and Cypher School. On the outbreak of war he took up full-time work at its headquarters, Bletchley Park.
Here he played a vital role in deciphering the messages encrypted by the German Enigma machine, which provided vital intelligence for the Allies. He took the lead in a team that designed a machine known as a bombe that successfully decoded German messages. He became a well-known and rather eccentric figure at Bletchley.
After the war, Turing turned his thoughts to the development of a machine that would logically process information. He worked first for the National Physical Laboratory (1945-1948). His plans were dismissed by his colleagues and the lab lost out on being the first to design a digital computer. It is thought that Turing's blueprint would have secured them the honour, as his machine was capable of computation speeds higher than the others. In 1949, he went to Manchester University where he directed the computing laboratory and developed a body of work that helped to form the basis for the field of artificial intelligence. In 1951 he was elected a fellow of the Royal Society.
In 1952, Turing was arrested and tried for homosexuality, then a criminal offence. To avoid prison, he accepted injections of oestrogen for a year, which were intended to neutralise his libido. In that era, homosexuals were considered a security risk as they were open to blackmail. Turing's security clearance was withdrawn, meaning he could no longer work for GCHQ, the post-war successor to Bletchley Park.
He committed suicide on 7 June, 1954.
Tim Berners Lee
Born: June 8, 1955 London
death: still alive (current age 59)
Tim Burners Lee is an English computer scientist more commonly known as 'The inventor of the World Wide Web'
Tim Berners Lee grew up in London. He studied physics at Oxford University and became a software engineer.
In 1980, while working at CERN, the European Particle Physics Laboratory in Geneva, he first described the idea of a global system, based on the concept of 'hypertext', that would allow researchers anywhere to share information. He also built a prototype called 'Enquire'.
WHAT ARE INPUTS AND OUTPUTS?
Computers only work with digital information. Any input that a computer receives must be digitised.
Often data has to be converted back to an analogue format when it's output, for example the sound from a computer's speakers.
The computer sits between the input and output devices. A computer program processes and digitises the input information. The result is then sent to an output device such as a screen.
Think of a DVD player
You click 'play' on your remote control, an input device. It digitises the input and sends this digital information to the DVD player.
The computer inside the DVD player processes this input information and works out what to do. It will start to read the DVD. The video and audio information from the DVD is then sent to the TV screen and the speakers, the output devices.
Think of a games console
When you are playing a game you are using a controller where you push a button or push the control stick to move a character.
These inputs are digitised and sent to the computer to be processed. The program processes the inputs and gives an output. In this case the character on screen moves as it has been programmed to.
What is a Drive?
A drive is a medium that is capable of storing and reading information that is not easily removed like a disk. The picture is an example of different drives listed in Microsoft Windows :My Computer.
In the example shown on this page, drive A: is the floppy drive, C: is the hard disk drive, D: and E: partitions of the hard drive, and F: is the CD-ROM drive. Typically the CD-ROM drive is the last drive so in most situations the hard drive is the C: drive and a CD-ROM or other disc drive is the D: drive.
ROM & RAM
ROM: Stands for read-only memory. The microprocessor can read from ROM, but it can’t write to it or modify it. ROM is permanent. Often, ROM chips contain special instructions for the computer — important stuff that never changes. The microprocessor can access information stored on a ROM chip whenever it needs to. The instructions are always there because they’re not erasable.
RAM: Stands for random access memory; refers to memory that the microprocessor can read from and write to. When you create something in memory, it’s done in RAM.
RAM is a fast temporary type of memory in which programs,applications and data are stored. Here are some examples of what's stored in RAM:
The motherboard serves to connect all of the parts of a computer together. The CPU,memory, hard drives, optical drives, video card, sound cardand other ports and expansion cards all connect to the motherboard directly or via cables.
The motherboard is the piece of computer hardware that can be thought of as the "back bone" of the PC.
The Motherboard is Also Known As
mainboard, mobo (abbreviation), MB (abbreviation), system board, logic board
In a desktop, the motherboard is mounted inside the case, opposite the most easily accessible side. It is securely attached via small screws through pre-drilled holes.
The front of the motherboard contains ports that all of the internal components connect to.
A single socket/slot houses the CPU. Multiple slots allow for one or more memory modules to be attached. Other ports reside on the motherboard which allow the hard drive and optical drive (and floppy drive if present) to connect via data cables.
Small wires from the front of the computer case connect to the motherboard to allow the power, reset and LED lights to function. Power from the power supply is delivered to the motherboard by use of a specially designed port.
Also on the front of the motherboard are a number of peripheral card slots. These slots are where most video cards, sound cards and other expansion cards are connected to the motherboard.
On the left side of the motherboard (the side that faces the back end of the desktop case) are a number of ports. These ports allow most of the computer's external peripherals to connect such as the monitor, keyboard, mouse, speakers, network cable and more.
All modern motherboards also include USB ports here, and increasingly other ports like HDMI and FireWire, that allow compatible devices to connect to your computer when you need them - devices like digital cameras, printers, etc.
The desktop motherboard and case are designed so that when peripheral cards are used,the sides of the cards fit just outside the back end, making their ports available for use.
what is CPU?
CPU (pronounced as separate letters) is the abbreviation for central processing unit.
Sometimes referred to simply as the central processor, but more commonly called processor, the CPU is the brains of the computer where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system.The CPU itself is an internal component of the computer. Modern CPUs are small and square and contain multiple metallic connectors or pins on the underside. The CPU is inserted directly into a CPU socket, pin side down, on the motherboard.
Each motherboard will support only a specific type (or range) of CPU, so you must check the motherboard manufacturer's specifications before attempting to replace or upgrade a CPU in your computer. Modern CPUs also have an attached heat sink and small fan that go directly on top of the CPU to help dissipate heat.
Components of a CPU
Two typical components of a CPU are the following:
The arithmetic logic unit (ALU), which performs arithmetic and logical operations.
The control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.
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