Computer System

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 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, 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 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

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)
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are smaller and less

powerful 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