This paper explains the importance of the different service levels of computer networking such as availability, reliability, response time and throughput. It aims to literate the people managing the network….
Computer System Introduction & Definitions — Computer is an electronic device that is used to solve various problems according to a set of instructions given to it — A computer is a programmable machine that receives input, stores and manipulates data, and provides output in a useful format Brief History of Computer — The first use of the word “computer” was recorded in 1613, referring to a person who carried out calculations, or computations, and word continued to be used in that sense until middle of 20th century From end of 19th century onwards though, word began to take on its more familiar meaning, describing a machine that carries out computations — The history of computer development is often referred to in reference to different generations of computing devices — Each generation of computer is characterized by a major technological development that fundamentally changed way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices Computer Generations First Generation (1940-1956 ) — The first computers used vacuum tubes for circuitry and agnetic 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, lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time Computer Generations First Generation (1940-1956 ) — Input was based on punched cards and paper tape, and output was displayed on printouts The UNIVAC and ENIAC computers are examples of firstgeneration computing devices — The UNIVAC was the first commercial computer delivered to a business client, the U. S. Census Bureau in 1951 Computer Generations Second Generation (1956-1963 ) — 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 energyefficient 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 Computer Generations Second Generation (1956-1963 ) — Second-generation 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. Computer Generations 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. Computer Generations Fourth Generation (1971-Present) — The microprocessor brought 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 nit 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 Computer Generations Fourth Generation (1971-Present) — 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
Computer Generations — Fifth Generation (Present and Beyond ) — 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 self-organization
Classification & Types of Computer — Supercomputer s… are used to process very large amounts of information including processing information to predict hurricanes, satellite images and navigation, and process military war scenarios Classification & Types of Computer — Mainframes … are used by government and businesses to process very large amounts of information Classification & Types of Computer — Mini -Computers… are similar to mainframes… they are used by business and government to process large amounts of information Classification & Types of Computer — Personal Computers (PC) — — — — — are smaller and less owerful than the others. They are used in homes, schools, and small businesses. There are 3 main types of PCs Desktop Portable (Notebook/Laptop) Hand -Held ( Mobile devices/ cellphone, PDAs) Classification & Types of Computer Desktop Classification & Types of Computer Portable Classification & Types of Computer Hand -Held Computer Hardware — These are physical parts of computer — These are things that can be seen & touched — System unit, Mouse, Keyboard, Monitor Computer Software — A set of computer instructions given to computer to solve problems — Stored inside computer memory — Can not be touched or seen