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Computer Handout - Copy

Sep 09, 2014




Generation of ComputersWe have so many types of computers mainly known as the calculating machines as their major function was calculating of numbers. These types of calculating machines have been manufactured in many generations and decades but time will fail us to mention or go through them all, thats why we selected the five recent generations which represents the major history of computers. First Generation (1940-1956) Vacuum Tubes The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions. First generation computers relied on machine language, the lowestlevel 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. The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951. Second Generation (1956-1963) Transistors Transistors 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. Secondgeneration computers still relied on punched cards for input and printouts for output. Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.

The first computers of this generation were developed for the atomic energy industry. Third Generation (1964-1971) Integrated Circuits 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. Fourth Generation (1971-Present) Microprocessors 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 computerfrom the central processing unit and memory to input/output controlson 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 Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and selforganization. DID YOU KNOW...? An integrated circuit (IC) is a small electronic device made out of a semiconductor material. The first integrated circuit was developed in the 1950s by Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor

THE PARTS OF A COMPUTER There are mainly two major component that makes up what we know as todays personal computers these are: The Hardware and the Software Hardware The hardware are the parts of the computer itself including the Central Processing Unit (CPU) and related microchips and microcircuitry, keyboards, monitors, case and drives (hard, CD, DVD, floppy, optical, tape, etc...). Other extra parts called peripheral components or devices include mouse, printers, modems, scanners, digital cameras and cards (sound, colour, video) etc... Together they are often referred to as a personal computer. Central Processing Unit - Though the term relates to a specific chip or the processor a CPU's performance is determined by the rest of the computer's circuitry and chips. Currently the Pentium chip or processor, made by Intel, is the most common CPU though there are many other companies that produce processors for personal computers. Examples are the CPU made by Motorola and AMD.

With faster processors the clock speed becomes more important. Compared to some of the first computers which operated at below 30 megahertz (MHz) the Pentium chips began at 75 MHz in the late 1990's. Speeds now exceed 3000+ MHz or 3 gigahertz (GHz) and different chip manufacturers use different measuring standards (check your local computer store for the latest speed). It depends on the circuit board that the chip is housed in, or the motherboard, as to whether you are able to upgrade to a faster chip. The motherboard contains the circuitry and connections that allow the various component to communicate with each other. Though there were many computers using many different processors previous to this I call the 80286 processor the advent of home computers as these were the processors that made computers available for the average person. Using a processor before the 286 involved learning a proprietary system and software. Most new software are being developed for the newest and fastest processors so it can be difficult to use an older computer system. Keyboard - The keyboard is used to type information into the computer or input information. There are many different keyboard

layouts and sizes with the most common for Latin based languages being the QWERTY layout (named for the first 6 keys). The standard keyboard has 101 keys. Notebooks have embedded keys accessible by special keys or by pressing key combinations (CTRL or Command and P for example). Ergonomically designed keyboards are designed to make typing easier. Hand held devices have various and different keyboard configurations and touch screens. Some of the keys have a special use. They are referred to as command keys. The 3 most common are the Control (CTRL), Alternate (Alt) and the Shift keys though there can be more (the Windows key for example or the Command key). Each key on a standard keyboard has one or two characters. Press the key to get the lower character and hold Shift to get the upper. Removable Storage and/or Disk Drives - All disks need a drive to get information off - or read - and put information on the disk - or write. Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term 'disk' and 'drive' are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files - or software - and the drive is the mechanism that runs the disk. Digital flash drives work slightly differently as they use memory cards to store information so there are no moving parts. Digital cameras also use Flash memory cards to store information, in this case photographs. Hand held devices use digital drives and many also use removable or built in memory cards. Mouse - Most modern computers today are run using a mouse controlled pointer. Generally if the mouse has two buttons the left one is used to select objects and text and the right one is used to access menus. If the mouse has one button (Mac for instance) it controls all the activity and a mouse with a third button can be used by specific software programs. One type of mouse has a round ball under the bottom of the mouse that rolls and turns two wheels which control the direction of the pointer on the screen. Another type of mouse uses an optical system to track the movement of the mouse. Laptop computers use touch pads, buttons and other devices to control the pointer. Hand helds use a combination of devices to control the pointer, including touch screens. Note: It is important to clean the mouse periodically, particularly if it becomes sluggish. A ball type mouse has a small circular panel that can be opened, allowing you to remove the ball. Lint can be removed carefully with a tooth pick or tweezers and the ball can be washed with mild detergent. A build up will accumulate on the small wheels in the

mouse. Use a small instrument or finger nail to scrape it off taking care not to scratch the wheels. Track