Computer Overview
Computer is an electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use.
It can process both numerical and non-numerical (arithmetic and logical) calculations.
Computer has four main functions:
i. Input data
ii. Process data
iii. Store data
iv. Output data· History of Computers
EVOLUTION OF COMPUTER.
1 Abacus: Counting machine.
2 Napier: Logs and bones (Concept used to transform multiplication to addition)
3 Pascal’s adding machine: Which has gears which can add number quickly.
5 Charles Babbage’s difference digit: Can calculate logarithm table to a higher degree of precision.
6 Babbage’s analytical engine: Can perform basic arithmetic operation plus comparison, which also include the concept of processing, storage, memory, input
7 Hollerith’s machine: Introduction electromechanically punch card calculator that using punch card for input, output and instructor.
8 Mark: Electromechanical computer was invited in 1943 which used to multiply digit.
GENERATIONS OF COMPUTER
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GENERATION
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DURATION
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TECHNOLOGY USED
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CHARACTERISTICS
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First Generation
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1946-1959
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Vacuum tubes
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1. They were very large in size.
2. They were difficult to program and use.
3. First generation computers were unreliable.
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Second Generation
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1959-1965
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Transistors
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1. Were smaller than vacuum tubes
2. They needed no warm up time
3. Consumes less energy
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Third Generation
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1965-1971
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Integrated Circuit
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1. IC was used instead of transistors in the third generation computers
2. They were fast and more reliable.
3. High level language was developed.
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Fourth Generation
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1971-1980
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VLSI Microprocessor based
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1. The fourth generation computers have microprocessor-based systems
2. They are the cheapest among all the computer generation.
3. The speed, accuracy and reliability of the computers were improved in fourth generation computers.
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Fifth Generation
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1980-Onwards
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ULSI Microprocessor
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1. A further refinement of input/output devices was developed.
2. Networking between the systems was developed
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· Type of computers
v Since the advent of the first computer different types and sizes of computers are offering different services.
v Computers can be as big as occupying a large building and as small as a laptop or a microcontroller in mobile & embedded systems.
There are four basic types of computers which are:
a) Super computer
b) Mainframe Computer
c) Minicomputer
d) Microcomputer
A. SUPERCOMPUTERS
v These are the most powerful computers in terms of performance and data processing
v These are specialized and task specific computers used by large organizations.
v These computers are used for research and exploration purposes, like NASA uses supercomputers for launching space shuttles, controlling them and for space exploration purpose.
v The supercomputers are very expensive and very large in size.
v It can be accommodated in large air-conditioned rooms; some super computers can span an entire building.
v In 1964, Seymour Cray designed the first supercomputer
Supercomputers are used in:
a) Space Exploration: Supercomputers are used to study the origin of the universe, the dark-matters.
b) Earthquake studies: Supercomputers are used to study the Earthquakes phenomenon. Besides that supercomputers are used for natural resources exploration, like natural gas, petroleum, coal, etc.
c) Weather Forecasting: Supercomputers are used for weather forecasting, and to study the nature and extent of Hurricanes, Rainfalls, windstorms, etc.
d) Nuclear weapons testing: Supercomputers are used to run weapon simulation that can test the Range, accuracy & impact of Nuclear weapons
B. MAINFRAME COMPUTERS
v Super-computers are the fastest computers with large data storage capacity, Mainframes can also process & store large amount of data.
v Although Mainframes are not as powerful as supercomputers, but certainly they are quite expensive
v Mainframe computers can be accommodated in large air-conditioned rooms because of its size.
C. MINICOMPUTER
v Minicomputers are used by small businesses & firms.
v Minicomputers are also called as “Midrange Computers”
v These are small machines with not as processing and data storage capabilities as super-computers & Mainframes
v These computers are not designed for a single user
v Individual departments of a large company or organizations use Mini-computers for specific purposes.
D. MICRO-COMPUTER
v Desktop computers, laptops, personal digital assistant (PDA), tablets & smart phones are all types of microcomputers.
v The micro-computers are widely used & the fastest growing computers.
v These computers are the cheapest among the other three types of computer
v The Micro-computers are specially designed for general usage like entertainment, education and work purposes.
v They are designed for use by one person at a time.
v Well known manufacturers of Micro-computer are Dell, Apple, Samsung, Sony & Toshiba.
v Desktop computers, Gaming consoles, Sound & Navigation system of a car, Notebooks, PDA’s, Tablet PC’s, Smartphone's, Calculators are all type of Microcomputers.
· Hardware parts of computer (Input, Output, Processing, and Storage)
3. Control Unit - This is the part of the unit, which directs information to the proper places in your computer, such as calculation of information by the ALU unit or to store and print material.
Hardware parts of computer(input, output, processing and storage)
Computer hardware is made up of the equipment used to make up you computer unit. These parts include your monitor, central processing unit (CPU), keyboard, mouse, printer, and modem. The computer is an electronic machine that performs the following four general operations:
Input
Storage
Processing
Inputs
The input hardware allows you to enter data into the computer. The primary devices used are the keyboard and mouse.
Keyboard - The keyboard looks like the typewriter. A numeric keypad is located to the right of the keyboard. Numeric keys have the same placement as a 10-key calculator, which allow the operator to enter data rapidly.
Mouse - The mouse is a device that allows you to control the movement of the insertion point on the screen. The operator places the palm of the hand over the mouse and moves it across a mouse pad, which provides traction for the rolling ball inside the device. Movement of the ball determines the location of the I beam on the computer screen. When the operator clicks the mouse the I beam becomes an insertion point which indicates the area you are working on the screen. You can also click the mouse and activate icons or drag to move objects and select text. There are other input devices, such as touch screen, joystick, modem, scanner, and voice recognition systems.
The input hardware allows you to enter data into the computer. The primary devices used are the keyboard and mouse.
Keyboard - The keyboard looks like the typewriter. A numeric keypad is located to the right of the keyboard. Numeric keys have the same placement as a 10-key calculator, which allow the operator to enter data rapidly.
Mouse - The mouse is a device that allows you to control the movement of the insertion point on the screen. The operator places the palm of the hand over the mouse and moves it across a mouse pad, which provides traction for the rolling ball inside the device. Movement of the ball determines the location of the I beam on the computer screen. When the operator clicks the mouse the I beam becomes an insertion point which indicates the area you are working on the screen. You can also click the mouse and activate icons or drag to move objects and select text. There are other input devices, such as touch screen, joystick, modem, scanner, and voice recognition systems.
Processing
The central processing unit or (CPU) is the "brain" of your computer. It contains the electronic circuits that cause the computer to follow instructions from ROM (read only memory) or from a program in RAM (random access memory). By following these instructions information is processed. The CPU contains three parts.
The central processing unit or (CPU) is the "brain" of your computer. It contains the electronic circuits that cause the computer to follow instructions from ROM (read only memory) or from a program in RAM (random access memory). By following these instructions information is processed. The CPU contains three parts.
1. Arithmetic Logic Unit - ALU is where the "intelligence" of the computer is located. It can add and compare numbers. To multiply 2 x 4 the computer would add 2 + 2 + 2 + 2. The ALU makes decisions by determining if a number is greater, less, or equal to the other number. Processing is completed in nanoseconds, which is a billionth of a second. 2. Memory - Two types of memory contained on a chip are RAM (Random Access Memory) or ROM (Read Only Memory). ROM memory has been installed on your computer by the manufacturer and can not be altered. ROM is the memory that determines all the basic functions of the operation of your machine, such as startup, shut down, and placing a character on the screen. RAM is temporary memory, which displays the information you are working on. RAM remembers what you see on your screen while you are working. Today's applications required large amounts of temporary memory, which may require you to upgrade and
Add more RAM memory.
3. Control Unit - This is the part of the unit, which directs information to the proper places in your computer, such as calculation of information by the ALU unit or to store and print material.
Outputs
Output devices such as a monitor or printer make information you input available for you to view or use.
A monitor's front is called a screen with a cathode ray tube (CRT) attached to the screen. Portable computers use a (LCD) liquid crystal display. Today's super video graphics array (SVGA) monitors display 256 sharp and clear colors.
Printers used with computers fall into two categories, impact or nonimpact. Impact printers, such as dot matrix print by contact against a ribbon making imprint on paper. Inkjet printers print images by not touching the paper. Ink jet printers spray ink onto the page while a laser printer works like a copying machine. Laser printers print a higher quality product but cost from $500 to $10,000 whereas an ink jet produces better quality than a dot matrix and can be purchased from $150 to $300. The personal computer user most commonly purchases an ink jet printer for home use.
Storage
Auxiliary storage devices, also called secondary storage devices, are used to store instructions and data when they are not being used in memory. Two types of auxiliary storage more often used on personal computers are floppy disks and hard disks. Also, CD-ROM drives are common.
Floppy Disks - A floppy disk is a circular piece of oxide-coated plastic that stores data as magnetic spots. Personal computers most commonly use floppy disks that are 3 � inches in diameter.
To read data stored one floppy disk or to store data on a floppy disk, you insert the floppy disk in a disk drive. If the disk is unused, you must format or initialize it before your computer will allow you to store data on it. Formatting organizes the tracks around the disk into pie like slices called sectors which make it possible for your computer to save and retrieve information. The density of the bits on the track and number of tracks on a disk determine the number of characters that can be stored.
Floppy disks are identified as being double density or high density. Most machines purchased after 1993 will use a high-density disk. A machine that has a double density drive can't process a high-density disk. Note the chart below for disk information.
Floppy Disk Capacity
Output devices such as a monitor or printer make information you input available for you to view or use.
A monitor's front is called a screen with a cathode ray tube (CRT) attached to the screen. Portable computers use a (LCD) liquid crystal display. Today's super video graphics array (SVGA) monitors display 256 sharp and clear colors.
Printers used with computers fall into two categories, impact or nonimpact. Impact printers, such as dot matrix print by contact against a ribbon making imprint on paper. Inkjet printers print images by not touching the paper. Ink jet printers spray ink onto the page while a laser printer works like a copying machine. Laser printers print a higher quality product but cost from $500 to $10,000 whereas an ink jet produces better quality than a dot matrix and can be purchased from $150 to $300. The personal computer user most commonly purchases an ink jet printer for home use.
Storage
Auxiliary storage devices, also called secondary storage devices, are used to store instructions and data when they are not being used in memory. Two types of auxiliary storage more often used on personal computers are floppy disks and hard disks. Also, CD-ROM drives are common.
Floppy Disks - A floppy disk is a circular piece of oxide-coated plastic that stores data as magnetic spots. Personal computers most commonly use floppy disks that are 3 � inches in diameter.
To read data stored one floppy disk or to store data on a floppy disk, you insert the floppy disk in a disk drive. If the disk is unused, you must format or initialize it before your computer will allow you to store data on it. Formatting organizes the tracks around the disk into pie like slices called sectors which make it possible for your computer to save and retrieve information. The density of the bits on the track and number of tracks on a disk determine the number of characters that can be stored.
Floppy disks are identified as being double density or high density. Most machines purchased after 1993 will use a high-density disk. A machine that has a double density drive can't process a high-density disk. Note the chart below for disk information.
Floppy Disk Capacity
Description
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Bytes
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5 � inch disk
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Double-sided, double-density
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360 KB
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Double-sided, high-density
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1.2MB
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3 � inch disk
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Double-sided, double-density
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720 KB
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Double-sided, high-density
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1.4 MB
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1.4 MB is equal to 500 pages of text.
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Floppy disks must be handled with care to preserve data. Follow the suggestions to protect your floppy disk.
1. Store in box or disk storage container.
2. Protect disk from dust.
3. Keep disk out of sunlight and away from extremes of hot or cold.
4. Don't press hard when writing on labels. Use a felt tip pen.
5. Insert metal side into drive first with the hub of the disk down.
6. Don't store disk near magnetic sources.
4. Don't press hard when writing on labels. Use a felt tip pen.
5. Insert metal side into drive first with the hub of the disk down.
6. Don't store disk near magnetic sources.
Hard Drive - Much like a floppy, the hard disk located inside the computer case is made of a stack of rotating disks, called platters. Data is recorded on a series of tracks that have been divided into sectors. Most computers have one hard drive, located inside the computer case. If a computer has one hard drive, it is called drive C. If a computer has additional hard drives, they are called drives D, E, and so on. A hard drive stores your programs. When you buy a new program, you must install the program files to your hard drive before you can use the program. A hard drive stores your data files such as documents,spreadsheets,andgraphics.
CD-ROM Storage - Since each CD-ROM can store 600 million bytes of data or 300,000 pages of text, they are today's answer to make you computer feel like a machine twice its size. Because of its external storage, you can use your machine to access an encyclopedia, games, graphics, and a variety of sources that use large amounts of memory.
CD-ROM Storage - Since each CD-ROM can store 600 million bytes of data or 300,000 pages of text, they are today's answer to make you computer feel like a machine twice its size. Because of its external storage, you can use your machine to access an encyclopedia, games, graphics, and a variety of sources that use large amounts of memory.
· Software parts of computer(System and application software)
What is computer software?
Computer software: Is any set of machine-readable instructions that directs a computer's processor to perform specific operations
Types of software
a) System software
b) Application software
System Software: Is a term referring to any computer software which manages and controls the hardware so that application software can perform a task.
Manages the computer’s resources, enables the various components of the computer to communicate, runs application software, and makes the hardware respond to the user’s needs.
System software includes four main types:
1. The operating system: provides an interface between the computer hardware and the user or the application software. The operating system has two primary functions:
a) First, it manages the computer's resources (the computer's hardware and any external devices). For example, the operating system controls the CPU, accesses RAM, executes programs, receives input from the keyboard or other input device, retrieves and saves data to and from secondary storage devices, displays data on the monitor, and controls the printer.
b) Second, the operating system contains instructions for running application software.
2. Language translators: convert application programs and any other software programs into the machine language that actually controls the computer's operations.
3. Network and communications software: operates the communications hardware in a computer so that it can transmit and receive information from other computers
Network and communications software requires two types of software: software for the PC operating system and software for the network operating system. In some cases, the latter comes built-in the former.
4. Utility programs: perform various specialized "housekeeping" tasks, such as file management, virus protection, disk defragmentation, program installation and uninstallation, file and disk back up, disk formatting, and providing screen saver programs. The user directly controls most utility programs, although some utility programs can be set to run automatically (e.g.; screen savers and anti-virus scanning).
The system software for a single-user PC is not nearly as complex as the system software for a multiuser mainframe computer. However, many of the features once found only in mainframe and minicomputer systems have been incorporated into PCs.
Application software: Is software that enables the user to direct the computer’s processing system in the tasks of manipulating and transforming input data into useful output information.
v This is the type of software with which most users interact.
v It is the usual interface between user and computer.
v Rarely do users directly manipulate systems software, especially the operating systems software.
v Application software can be either specific purpose or general purpose software.
· Computer impacts and applications.
Computer Application
v An aid to management: The computer can also be used as a management tool to assist in solving business problems.
v Banking: Branches are equipped with terminals giving them an online accounting facility and enabling them to information as such things as current balances, deposits, overdrafts and interest charges.
v Industrial Application: In industry, production may be planned, coordinated and controlled with the aid of a computer.
v Engineering Design: Computer help in calculating that all the parts of a proposed design are satisfactory and also assist in the designing.
v Meteorology: Data is recorded at different levels of atmosphere at different places, using remote sensors carried on a satellite.
v Air Travel: Small computers are installed as a part of the plane's equipment.
v Road Traffic Control: Computers assist with the control of traffic lights.
v Telephones: Computerized telephone exchanges handle an ever increasing volume of calls very efficiently.
v Medicine: Computers are widely used in hospitals for such task as maintaining drugs, surgical equipment’s and linen, for payroll and also for checkup and treatment of diseases.
v In addition computers are also used for recording and film studios, research, military, etc.
Computers have both positive and negative impact in our daily life as well as in our social life.
Positive Impact of Computer
v The work can be done in very less time.
v More information can be stored in small space.
v Multitasking and multiprocessing capabilities of data.
v Easy to access data.
v Impartiality.
v Documents can be kept secret.
v Error free result.
v It can be used for various purposes. i.e. It can be used in any type of work.
Negative Impact of Computer
v Highly expensive.
v Accidents.
v Data piracy.
v Increased Unemployment.
v Huge data and information can be lost sometimes.
v Fast changing computer technology.
v Service distribution.
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