Lecture 01
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INTRODUCTION TO COMPUTER LECTURE 01
WHAT IS A COMPUTER? A computer is an electronic device, which executes our statements according to our instructions at very high speed. OR A computer is an electronic device, which takes input from user process it according to our instructions and then display the result. Characteristics of computers A computer has the following tremendous characteristics. i) Speed ii) Accuracy iii) Diligence iv) Versatility v) Power of Remembering i Speed A computer is a very fast device it can perform in a few seconds the amount of work that a human being can do in an entire years. The speed of computer is not measured in seconds or milliseconds but it is in microseconds, nanoseconds and even Pico seconds. ii) Accuracy A computer performs each and every calculation with quite accuracy as compare to human being. Errors can occur in a computer, but these are mainly due to human rather than computer weaknesses. iii) Diligence. A computer is free from tiredness and lack concentration and it can work for hours together without creating any error or looseness. If ten millions calculations have to be performed, a computer will perform the ten millionth calculation with exactly the same accuracy and speed as the first one. iv) Versatility Versatility is one of the most wonderful things about the computer. One moment, it is preparing the results of the particular examination, the nest moment it is busy in preparing electricity bills and in between it may be helping an office secretary to trace an important letter in a seconds. v) Power of remembering A computer can store and recall any amount of information because of its secondary storage capacity. Every piece of information can be retained as long as desired by the user and can be recalled as and when requires. Even after several years, the information recalled would be as accurate as on the day when it was fed to computer. 1
INTRODUCTION TO COMPUTER LECTURE 01
BRIEF HISTORY OF COMPUTER There are five computer generations known throughout the complete history of computer. Each generation has been discussed below. i) First Generation (1942 to 1955) The machines were invented during this period, consist of vacuum tube, which was a fragile, glass device that could control and amplify electronic signals. These vacuum tube computers are referred to as first generation computers. Advantages a) Vacuum tubes were the only electronic components available during those days. b) Vacuum tube technology made possible the advent of electronic digital computers. c) These computers were the fastest calculating device of their time. Disadvantages a) Too bulky in size b) Unreliable c) Air conditioning required. d) Non portable e) Limited commercial use. ii) Second Generation (1955 to 1964) The transistor, a smaller and more reliable successor to vacuum tube, was invented in 1947. However the computer that used transistors were not produced in quantity until over a decade later. The second generation emerged with transistor being the brain of computer. Advantages a) Small in size as compare to the first generation computer. b) More reliable. c) Less heat generated. d) Better portability Disadvantages a) Air-Conditioning required. b) Commercial production was difficult and costly. iii) Third Generation (1964 to 1975) advance in electronics technology continued and the advent of “microelectronics” technology made it possible to integrate large number of circuit elements into very small surface of silicon known as “chip” this new technology was called “Integrated Circuit” (ICs). The third generation was based on IC technology and the computer that was designed with the use of integrated circuits was called third generation computers. Advantages a) Smaller in size as compares to previous generation computers. b) More reliable. 2
INTRODUCTION TO COMPUTER LECTURE 01
iv)
v)
c) Lower heat generator. d) Speedy e) Easily portable. Disadvantages a) Air-Conditioning required. b) Highly sophisticated technology required for the manufacture of IC Fourth Generation ( 1975 to Onwards) Initially the integrated circuits contained only about ten twenty components; this technology was named small-scale integration (SSI). Later, with the advancement in technology for manufacturing ICs, it became possible to integrate up to a hundred components on a single chip. This technology came to be known as a medium scale integration (MSI). Then came the era of large-scale integration (LSI) when it was possible to integrate over 30,000 components on to a single chip. Effort is still on for further manufacturization and it is expected that more than one million components will be integrated on a single chip known as very large scale integration (VLSI). Advantages a) Smallest in size. b) Very reliable c) Heat generated is negligible. d) No air conditioning required. e) Hardware failure is negligible. f) Easily portable g) Cheapest Disadvantages a) Highly sophisticated technology required for the manufacture of LSI chips. Fifth Generation (Yet to come) Unlike the last four generations, which naturally followed its predecessor, the fifth generation will be totally different. In structure it will be parallel and will be able to do multiple tasks simultaneously. In function it will not be algorithmic. In nature, it will not do just data processing, but knowledge processing.
THE MULTIPURPOSE TOOL. A computer is used for almost in every field of life. * The first modern computer was used for complex numerical tasks. * Modern medicine uses computers in many ways. E.g. computers are used to assist in surgical procedures and to diagnose illnesses. * Educators are interested in computers as tools for interactive learning. * The scientific community uses computers to do research and exchange information with colleagues around the world.
3
INTRODUCTION TO COMPUTER LECTURE 01 * * *
Engineers and architectures use computers to design objects and structure with the help of CAD (Computer Aided Design) tools. The government is a major user of computers; many governmental agencies now even host their own World Wide Web sites. Filmmakers use computers to create special effects.
AN OVERVIEW OF THE COMPUTER SYSTEM Every computer system consists of four parts. i) Hardware, also known simply as the computer. ii) Software also known as programs. iii) Data, which the system converts into information. iv) People also known as user. i)
ii)
iii)
iv)
Hardware Any part of the computer, which is tangible, called Hardware. Or the complement of software is called hardware. Hardware consists of interconnected electronic devices that you can use to control the computers operation input and output. Software The parts of computer, which are intangible, are called software. Or complement of hardware is called software. In other words the term software refers to sets of electronic instructions that tell the hardware what to do. These sets of instructions are also known as programs. E.g. you will possibly use a word processing program to enter, edit and format text documents, such as letters, memos and reports. Data Data refers to the raw facts that computer can manipulate. Data can consist of letters, numbers, sound or images. Data after processing is called information. User Last part of the computer system is the person who uses the computer. In discussion about computers, people are usually referred to as users.
LOOKING INSIDE THE MACHINE A computer consists of the following major parts. i) Processor. ii) Memory iii) Input and Output devices iv) Storage devices.
i)
The Processor 4
INTRODUCTION TO COMPUTER LECTURE 01
ii)
iii)
iv)
6.
The procedure that transforms raw data into the useful information is called processing. To perform this transformation, the computer uses two components, the processor and memory. Processor is like brain of the computer, the part that organizes and carries out instructions that come from either the user or the software. In a personal computer, the processor usually consists of one or more microprocessors, which are slivers of silicon or other material attached with many tiny electronic circuits. The microprocessor is plugged into a circuit board. The circuit board to which the microprocessor is connected is called motherboard. Memory Memory is like an electronic scratch pad inside the computer. When you launch a program, it is loaded into and run from memory. Data used by the program is also loaded into memory for fast access. As you enter new data into a computer it is also stored in memory but only temporarily. The most common type of memory is called random access memory (RAM). This is volatile memory. The speed of computer is also depending upon it. The most common measurement unit for describing the computers memory is the byte. The amount of memory it takes to store a single character such as letter, alphabet or a numeral. Its large units are kilobyte, megabyte, gigabyte and terabyte. Input and Output Devices Input devices accept data and instructions from the user. The most common input device is the keyboard, which accepts letters, numbers and commands from the user. Another popular input device is the mouse, which lets you select options from on-screen menus. Other popular input devices are trackballs; touch pads, joysticks, scanner, digital cameras and microphones. Output devices returned processed data back to the user. The most common output devices are the display screen, known as monitor and the printer. The computer sends output to the monitor, when the user needs only to see the soft copy of the output. It sends output to the printer when the user needs a paper copy also called hard copy. Storage devices Computer also needs a place to keep program files and related data when it is not using them. The purpose of storage is to hold data. Remember the distinction between storage and memory. Their functions are the similar, but they work in different ways. The most common storage medium is the hard disk, floppy disk, tape and CD(s).
SOFTWARE BRINGS THE MACHINE TO LIFE 5
INTRODUCTION TO COMPUTER LECTURE 01 A specific set of instructions that drive a computer to perform a specific task is called a program. A combination of these programs is called software. When a computer is using a particular program, it is said to be running or executing that program. These programs tell the machine what to do, without them a computer could not do any thing. The software is divided into two major categories. i) Application Software ii) System Software i) Application Software Programs that helps the people in performing some specific tasks are called application software. Thousands of applications are available, however, some major categories are as follows. * Word processing software * Spreadsheets * Database managements software * Graphics, multimedia and presentation applications * Entertainment and education software * Communication software. ii) System Software System software is also known as system package, is a set of one or more programs design to control the operations of a computer system. One major type of system software called operating system. Operating system tells the computer how to use its own components. Operating system is a program that creates an interface between user and computer hardware.
THE SHAPES OF COMPUTERS TODAY Computers come in many sizes and varying capabilities. Major categories are as follows. i) Supercomputer ii) Mainframe Computer iii) Minicomputer iii) Microcomputer or Personal Computer (PC) i)
Supercomputers Supercomputers are the more powerful computers made. They are built to process huge amount of data. For example scientists build models of complex processes and simulate processes on a super computer. One such process is nuclear fission.
ii)
Mainframe Computers 6
INTRODUCTION TO COMPUTER LECTURE 01
iii)
iv)
The largest type of computer in common use is the mainframe. Mainframe computers are used where many people in a large organization need frequently access to the same information, which is usually organized into one or more huge database. Minicomputers These computers are smaller in size than mainframe computer. The capabilities of a minicomputer lies some where between those of mainframes and those of personal computers. For this reason, mini computers are often referred to as mid range computer. Like mainframes, minicomputer can handle much more input and output than personal computer can. Although some minis are designed for a single user, many can handle dozens or even hundred of terminals. Microcomputers The term microcomputer and personal computer are interchangeable, but PC which stands for personal computer some times has more specific meanings. In 1981 IBM called its first microcomputer the IBM-PC. One source of PC’s popularity is the rate at which improvements are made in the technology. Microprocessors, memory chips and storage devices keep making gains in speed and capacity while physical size and price remains stable or in some cases are reduced. For example compared to the physical PC of the ten years ago a machine of the same price today will have at least eight times as much RAM, about 50 times more storage capacity.
7
WHAT IS A COMPUTER? A computer is an electronic device, which executes our statements according to our instructions at very high speed. OR A computer is an electronic device, which takes input from user process it according to our instructions and then display the result. Characteristics of computers A computer has the following tremendous characteristics. i) Speed ii) Accuracy iii) Diligence iv) Versatility v) Power of Remembering i Speed A computer is a very fast device it can perform in a few seconds the amount of work that a human being can do in an entire years. The speed of computer is not measured in seconds or milliseconds but it is in microseconds, nanoseconds and even Pico seconds. ii) Accuracy A computer performs each and every calculation with quite accuracy as compare to human being. Errors can occur in a computer, but these are mainly due to human rather than computer weaknesses. iii) Diligence. A computer is free from tiredness and lack concentration and it can work for hours together without creating any error or looseness. If ten millions calculations have to be performed, a computer will perform the ten millionth calculation with exactly the same accuracy and speed as the first one. iv) Versatility Versatility is one of the most wonderful things about the computer. One moment, it is preparing the results of the particular examination, the nest moment it is busy in preparing electricity bills and in between it may be helping an office secretary to trace an important letter in a seconds. v) Power of remembering A computer can store and recall any amount of information because of its secondary storage capacity. Every piece of information can be retained as long as desired by the user and can be recalled as and when requires. Even after several years, the information recalled would be as accurate as on the day when it was fed to computer. 1
INTRODUCTION TO COMPUTER LECTURE 01
BRIEF HISTORY OF COMPUTER There are five computer generations known throughout the complete history of computer. Each generation has been discussed below. i) First Generation (1942 to 1955) The machines were invented during this period, consist of vacuum tube, which was a fragile, glass device that could control and amplify electronic signals. These vacuum tube computers are referred to as first generation computers. Advantages a) Vacuum tubes were the only electronic components available during those days. b) Vacuum tube technology made possible the advent of electronic digital computers. c) These computers were the fastest calculating device of their time. Disadvantages a) Too bulky in size b) Unreliable c) Air conditioning required. d) Non portable e) Limited commercial use. ii) Second Generation (1955 to 1964) The transistor, a smaller and more reliable successor to vacuum tube, was invented in 1947. However the computer that used transistors were not produced in quantity until over a decade later. The second generation emerged with transistor being the brain of computer. Advantages a) Small in size as compare to the first generation computer. b) More reliable. c) Less heat generated. d) Better portability Disadvantages a) Air-Conditioning required. b) Commercial production was difficult and costly. iii) Third Generation (1964 to 1975) advance in electronics technology continued and the advent of “microelectronics” technology made it possible to integrate large number of circuit elements into very small surface of silicon known as “chip” this new technology was called “Integrated Circuit” (ICs). The third generation was based on IC technology and the computer that was designed with the use of integrated circuits was called third generation computers. Advantages a) Smaller in size as compares to previous generation computers. b) More reliable. 2
INTRODUCTION TO COMPUTER LECTURE 01
iv)
v)
c) Lower heat generator. d) Speedy e) Easily portable. Disadvantages a) Air-Conditioning required. b) Highly sophisticated technology required for the manufacture of IC Fourth Generation ( 1975 to Onwards) Initially the integrated circuits contained only about ten twenty components; this technology was named small-scale integration (SSI). Later, with the advancement in technology for manufacturing ICs, it became possible to integrate up to a hundred components on a single chip. This technology came to be known as a medium scale integration (MSI). Then came the era of large-scale integration (LSI) when it was possible to integrate over 30,000 components on to a single chip. Effort is still on for further manufacturization and it is expected that more than one million components will be integrated on a single chip known as very large scale integration (VLSI). Advantages a) Smallest in size. b) Very reliable c) Heat generated is negligible. d) No air conditioning required. e) Hardware failure is negligible. f) Easily portable g) Cheapest Disadvantages a) Highly sophisticated technology required for the manufacture of LSI chips. Fifth Generation (Yet to come) Unlike the last four generations, which naturally followed its predecessor, the fifth generation will be totally different. In structure it will be parallel and will be able to do multiple tasks simultaneously. In function it will not be algorithmic. In nature, it will not do just data processing, but knowledge processing.
THE MULTIPURPOSE TOOL. A computer is used for almost in every field of life. * The first modern computer was used for complex numerical tasks. * Modern medicine uses computers in many ways. E.g. computers are used to assist in surgical procedures and to diagnose illnesses. * Educators are interested in computers as tools for interactive learning. * The scientific community uses computers to do research and exchange information with colleagues around the world.
3
INTRODUCTION TO COMPUTER LECTURE 01 * * *
Engineers and architectures use computers to design objects and structure with the help of CAD (Computer Aided Design) tools. The government is a major user of computers; many governmental agencies now even host their own World Wide Web sites. Filmmakers use computers to create special effects.
AN OVERVIEW OF THE COMPUTER SYSTEM Every computer system consists of four parts. i) Hardware, also known simply as the computer. ii) Software also known as programs. iii) Data, which the system converts into information. iv) People also known as user. i)
ii)
iii)
iv)
Hardware Any part of the computer, which is tangible, called Hardware. Or the complement of software is called hardware. Hardware consists of interconnected electronic devices that you can use to control the computers operation input and output. Software The parts of computer, which are intangible, are called software. Or complement of hardware is called software. In other words the term software refers to sets of electronic instructions that tell the hardware what to do. These sets of instructions are also known as programs. E.g. you will possibly use a word processing program to enter, edit and format text documents, such as letters, memos and reports. Data Data refers to the raw facts that computer can manipulate. Data can consist of letters, numbers, sound or images. Data after processing is called information. User Last part of the computer system is the person who uses the computer. In discussion about computers, people are usually referred to as users.
LOOKING INSIDE THE MACHINE A computer consists of the following major parts. i) Processor. ii) Memory iii) Input and Output devices iv) Storage devices.
i)
The Processor 4
INTRODUCTION TO COMPUTER LECTURE 01
ii)
iii)
iv)
6.
The procedure that transforms raw data into the useful information is called processing. To perform this transformation, the computer uses two components, the processor and memory. Processor is like brain of the computer, the part that organizes and carries out instructions that come from either the user or the software. In a personal computer, the processor usually consists of one or more microprocessors, which are slivers of silicon or other material attached with many tiny electronic circuits. The microprocessor is plugged into a circuit board. The circuit board to which the microprocessor is connected is called motherboard. Memory Memory is like an electronic scratch pad inside the computer. When you launch a program, it is loaded into and run from memory. Data used by the program is also loaded into memory for fast access. As you enter new data into a computer it is also stored in memory but only temporarily. The most common type of memory is called random access memory (RAM). This is volatile memory. The speed of computer is also depending upon it. The most common measurement unit for describing the computers memory is the byte. The amount of memory it takes to store a single character such as letter, alphabet or a numeral. Its large units are kilobyte, megabyte, gigabyte and terabyte. Input and Output Devices Input devices accept data and instructions from the user. The most common input device is the keyboard, which accepts letters, numbers and commands from the user. Another popular input device is the mouse, which lets you select options from on-screen menus. Other popular input devices are trackballs; touch pads, joysticks, scanner, digital cameras and microphones. Output devices returned processed data back to the user. The most common output devices are the display screen, known as monitor and the printer. The computer sends output to the monitor, when the user needs only to see the soft copy of the output. It sends output to the printer when the user needs a paper copy also called hard copy. Storage devices Computer also needs a place to keep program files and related data when it is not using them. The purpose of storage is to hold data. Remember the distinction between storage and memory. Their functions are the similar, but they work in different ways. The most common storage medium is the hard disk, floppy disk, tape and CD(s).
SOFTWARE BRINGS THE MACHINE TO LIFE 5
INTRODUCTION TO COMPUTER LECTURE 01 A specific set of instructions that drive a computer to perform a specific task is called a program. A combination of these programs is called software. When a computer is using a particular program, it is said to be running or executing that program. These programs tell the machine what to do, without them a computer could not do any thing. The software is divided into two major categories. i) Application Software ii) System Software i) Application Software Programs that helps the people in performing some specific tasks are called application software. Thousands of applications are available, however, some major categories are as follows. * Word processing software * Spreadsheets * Database managements software * Graphics, multimedia and presentation applications * Entertainment and education software * Communication software. ii) System Software System software is also known as system package, is a set of one or more programs design to control the operations of a computer system. One major type of system software called operating system. Operating system tells the computer how to use its own components. Operating system is a program that creates an interface between user and computer hardware.
THE SHAPES OF COMPUTERS TODAY Computers come in many sizes and varying capabilities. Major categories are as follows. i) Supercomputer ii) Mainframe Computer iii) Minicomputer iii) Microcomputer or Personal Computer (PC) i)
Supercomputers Supercomputers are the more powerful computers made. They are built to process huge amount of data. For example scientists build models of complex processes and simulate processes on a super computer. One such process is nuclear fission.
ii)
Mainframe Computers 6
INTRODUCTION TO COMPUTER LECTURE 01
iii)
iv)
The largest type of computer in common use is the mainframe. Mainframe computers are used where many people in a large organization need frequently access to the same information, which is usually organized into one or more huge database. Minicomputers These computers are smaller in size than mainframe computer. The capabilities of a minicomputer lies some where between those of mainframes and those of personal computers. For this reason, mini computers are often referred to as mid range computer. Like mainframes, minicomputer can handle much more input and output than personal computer can. Although some minis are designed for a single user, many can handle dozens or even hundred of terminals. Microcomputers The term microcomputer and personal computer are interchangeable, but PC which stands for personal computer some times has more specific meanings. In 1981 IBM called its first microcomputer the IBM-PC. One source of PC’s popularity is the rate at which improvements are made in the technology. Microprocessors, memory chips and storage devices keep making gains in speed and capacity while physical size and price remains stable or in some cases are reduced. For example compared to the physical PC of the ten years ago a machine of the same price today will have at least eight times as much RAM, about 50 times more storage capacity.
7
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