SEG 2100 Software Design II

INTRODUCTION OF COMPUTERLecture #2 COMPUTER AND ITS USES

ByShahid Naseem (Lecturer)

1LECTURE OUTLINES2LECTURE OUTLINESType of ComputersAnalog ComputerDigital ComputerHybrid ComputerComponents of ComputerInput DevicesOutput DevicesCPUMemory UnitSecondary Storage Devices

Introduction of Computer (Civil Engineering Department)3TYPE OF COMPTERSAnalog ComputersAnalog means continuously varying in quantity. The analog computers accept input data in continuous form and output is obtained in the form of graph. It means that these computers accept input and give output in the form of analog signals. e.g. Voltage, Current, Sound, Speed, Temperature, Pressure, Thermometer, Analog clock, speedometer,tire-pressure gauge etc.

The Analog computers are usually built for special purpose. They have very high speed computing elements used to process physical quantities. The analog computers have low memory size and have fewer functions. These are very fast in processing but output return is not very accurate.

Introduction of Computer (Civil Engineering Department)continue4TYPE OF COMPTERSUsesThe analog computers are used in industrial units to control various processes. They are also used in different fields of engineering and medicine.Characteristics of Analog ComputerThe important characteristics of analog computers are as follows:The speed of analog computer is fast as computer to digital computer.These computers have no state.These computers have limited memory.The result of these computers is not reliable as computer to digital computers.These computers become the base for digital computers.

Introduction of Computer (Civil Engineering Department)5ANALOG VOLTMETERIntroduction of Computer (Civil Engineering Department)

6TYPE OF COMPTERSDigital computersDigital means discrete. It refers to binary system, which consists of only two digits i.e. 0 and 1. Digital data consists of binary data represented by OFF (low) and ON (high) electrical pulses. These pulses are increased and decreased in discontinuous form rather that in continuous form.

In digital computers, quantities are counted rather than measured. A digital computer operates by counting numbers or digits and give output in digital form.ExamplesIBM PC, Apple Macintosh Computers, calculators, digital watches and digital thermometers etc.

Introduction of Computer (Civil Engineering Department)continue7TYPE OF COMPTERSUses Today, most of the computers used in offices and homes are digital computers. Characteristics of Digital ComputerThe important characteristics of digital computers are as follows:Give accurate result.Having high speed of data processingCan store large amount of data.Easy to program and are general purpose in use.Consume low energy.

Introduction of Computer (Civil Engineering Department)8DIGITAL METERIntroduction of Computer (Civil Engineering Department)

9TYPE OF COMPTERSHybrid computersThe hybrid computers have best combined features of both analog and digital computers. These computers contain both the digital and analog components. In hybrid computers, the users can process both the continuous and discrete data. These are special purposes computers. They are very fast and accurate. sUses:These computers are used in scientific fields. In hospitals, these are used to watch patients health condition in ICU (Intensive Care Unit). These are used in spaceships, missiles etc.

Introduction of Computer (Civil Engineering Department)10HYBRID COMPUTERIntroduction of Computer (Civil Engineering Department)

11COMPONENTS OF COMPTERSA computer consists of different components. Each component performs a specific function in the computer. These components can communicate with each other. Arrangement and connections of various components of the computer system is called Computer Architecture. The physical parts of a computer are known as computer hardware. You can touch, see and feel the hardware. The hardware components are Input devicesOutput devices Central processing unit.Memory unit.Secondary storage devices.

Introduction of Computer (Civil Engineering Department)12INPUT DEVICESThe data and instructions are given to the computer as input. The input device is used to give input to the computer. It accepts input (data & program instructions)in a form that a compute can use and then enters into the computers.

Most commonly used input devices is given below.KeyboardMouseTouch PadTrackbalJoy StickLight PenDigital ScannerDigital CameraMicrophoneIntroduction of Computer (Civil Engineering Department)13INPUT DEVICESKeyboardKeyboard is the most commonly used input device. It is mostly used to enter test and numeric type data into the computer. Keyboard looks like a type writer keypad. But a computer keyboard has some special keys used to perform special functions.Parts of KeyboardFunction keysMain keyboardNumeric keysAdditional keysIntroduction of Computer (Civil Engineering Department)

14INPUT DEVICESTouchpadTouch Pad is pressure sensitive pointing input device. Touch pad is also known as trackpad. It is also stationary device like trackball but is has no moving parts. It is a small flat surface over which we slide our fingertip to move the pointer on screen for pointing a desired icon. As we slide our fingertip on the flat surface of Touch Pad, the pointer moves on the screen. Introduction of Computer (Civil Engineering Department)

15INPUT DEVICESTrackballA trackball is also a pointing input device. It performs functions like a mouse but it is a stationary device. It has a moveable ball on its top. The ball is rotated or rolled with figure to control the movement of pointer on the screen. Like mouse, a trackball also has buttons used to send the commands to computer.The trackball is usually available with laptop computer. It is fixed on its keyboard. The laptop computers are used by the travelling users. The trackball fulfils the needs of those users that have no flat surface to roll the traditional mouse.Introduction of Computer (Civil Engineering Department)

16INPUT DEVICESMouseA mouse is a pointing input device. It looks like a mouse. It is most commonly used in Windows environment on the person computers. It is used to control the cursor or pointer on the screen and to give commands to the computer. It is very easy to use. The commands can be given to the computer very easily and quickly.

A mouse is connected to a serial port or USB port on the system unit. The mouse has two or three buttons on its top. Usually, mouse is used to select any icon or option by pointing the mouse pointer on it and clicking one of the buttons of the mouse to perform an action.

A mouse also allows the user to create graphics such as lines, curves and free hand shapes on the screen. Introduction of Computer (Civil Engineering Department)17MOUSEIntroduction of Computer (Civil Engineering Department)

18INPUT DEVICESJoystickJoystick is also a pointing device. It consists of a vertical handle like a gearshift lever mounted on a base and with one or two buttons. The vertical handle is used to control the movement of pointer on the screen. The button of the joystick is pressed to activate certain event or action. The joystick is basically used to play video games. It is also used in some computer-aided design system

Introduction of Computer (Civil Engineering Department)

19INPUT DEVICESLight PenThe light pen is a handheld pointing input device. It is a light-sensitive stylus, or pen-like device. It is connected with the computer by a wire. Light pen has a photocell mounted at its front end. When the front end of the pen is touched with the monitor screen, the photocell detects or senses a position on display screen. This device also has a button. The use points the object to be selected on the display screen and then presses a button on the light pen.Light pen is used in Personal Digital Assistant (PDA) and other types of handheld computers.The light pen input device is generally used with designing software. A spot appears on the display screen at the location where pen is touched and it is sensed by the photocell. The computer program controlled the input signals of this device.

Introduction of Computer (Civil Engineering Department)20LIGHT PENIntroduction of Computer (Civil Engineering Department)

21INPUT DEVICESDigital ScannerDigital scanner is also called Optical Scanner. It is a very popular input device. It is light sensing input device. It reads images and text printed on the paper and then translates into electronic form that can be processed and stored by the computer. The scanner uses the laser technology to scan the image of the printed paper and store it into the computer. Once an image is scanned, it can be used by used for following purposes.It can be stored in a disk for future use.It can be printed on the paperIt can be attached to an e-mail message.It can be transferred to the paint program for processing or it can be directly opened in the word processing program for editing. To translate the image into text for editing Optical Character Recognition (OCR) software is used. For editing a scanned photo, Adobe Photoshop graphic software is used.

Introduction of Computer (Civil Engineering Department)22SCANNERIntroduction of Computer (Civil Engineering Department)

23INPUT DEVICESDigital CameraA digital camera is an input device. It is used to take pictures in digital form. It does not use traditional camera film. It uses a light-sensitive processor chip to capture photographic images in digital form. These images are stored on a small diskette inserted in the camera or on flash memory chip. These pictures are then loaded to computer for further processing.MicrophoneMicrophone is used for recording the voice directly to the computer.

Introduction of Computer (Civil Engineering Department)

24OUTPUT DEVICESThe processed data is also known as output. The output device is used to get output from the computer. It displays processed data or results in a form the user wants.

Most commonly used output devices is given below.MonitorsPrintersPlottersSpeakersProjectorsFax MachinesIntroduction of Computer (Civil Engineering Department)25OUTPUT DEVICESMonitorsMonitor is commonly used output device. It is used as softcopy output device. The output may be in the form of text, graphics and video. It also helps the users to input correct data into the computer. Monitor is also referred to as display screen.

Monochrome Monitor (720 x 350) and maximum color is 1.

Color Monitors ( VGA 640 x 480 and maximum color is 16, XGA 1024 x 768 and maximum colors are 256)Cathode Ray Tube (CRT) monitors.Flat-Panel Monitors.Touch Screen Monitors.sIntroduction of Computer (Civil Engineering Department)26MONITORSIntroduction of Computer (Civil Engineering Department)

27OUTPUT DEVICESPrintersThese are most commonly used output devices used to get prints of documents on the paper. The output printed on the paper is called hardcopy. The hardcopy is also called as printout. The printout resolution is measured in dots per inch. There are two types of printers.1. Impact Printers2. Non-Impact printersImpact printersThe printers that produce output on paper with striking the paper are known as impact printer. Impact printers work like typewriter. They print characters and graphics on the paper by striking of print hammer or wheel against an inked ribbon. The images of the characters or graphics is created on the paper.Dot Matrix PrintersDaisy Wheel PrintersLine PrintersIntroduction of Computer (Civil Engineering Department)28OUTPUT DEVICESDot Matrix PrinterA dot matrix printer is an impact printer. It makes a hardcopy by printing one character at a time. Its printing speed varies from 200 to 1000 characters per minute.Daisy Wheel PrinterDaisy wheel printer is also an impact printer. It is similar to typewriter. It has a print wheel with series of petals. This wheel is known as daisy wheel. Each petal of the daisy wheel contains a character at its end. A motor rotates the wheel. When the desired character reaches at the print position on the paper, a hammer strikes a petal against the ribbon. The printing speed of these printers is in the range of 10 to 100 characters per second.

Daisy wheel printers are slower than dot-matrix printers but its printing quality is better than dot-matrix printer.Introduction of Computer (Civil Engineering Department)29IMPACT PRINTERSIntroduction of Computer (Civil Engineering Department)

Dot Matrix PrinterDaisy Wheel PrinterLine Printer30OUTPUT DEVICESLine PrinterLine printer is an impact printer. It is very fast printer. It prints a complete line of characters at a time. The printing speed of line printer is measured in 1 line to 3000 lines per minute.Non-Impact PrintersThe printers that produce output on paper without striking the paper are known as non-impact printers. These printers are faster and produce high quality output than impact printers. They use inkjet, electrostatic and thermal technologies for printing.Laser PrinterInkjet PrinterThermal PrinterIntroduction of Computer (Civil Engineering Department)31NON-IMPACT PRINTERSIntroduction of Computer (Civil Engineering Department)Laser Jet PrinterInkjet PrinterThermal Printer

32OUTPUT DEVICESLaser PrinterLaser stands for Light Amplification by Simulated Emission of Radiation. A laser printer is the fastest and high quality non-impact printer. It works like a photocopier. The laser printer uses a laser beam to transfer images of output on the paper.

The laser printer has a special drum inside it. The image of output is created on the drum by throwing magnetic ink power (called toner) in the form of microscopic dots. These dots can be from 300dpi to 1200 dpi.

The printing speed of these printers is about 4 to 32 pages per minute. Introduction of Computer (Civil Engineering Department)33OUTPUT DEVICESInk-Jet PrinterInk-Jet printer is a non-impact printer. It creates output on paper by spraying small electrically charged droplets (drops) of liquid ink. Inkjet printer has a print- head that can spray very fine drops of ink. It consists of print cartridge filled with liquid ink and has small nozzles in the form of matrix.

The inkjet printers have resolution ranging froom300 to 720 dpi. The printing speed of ink-jet printer is from 1 to 6 pages per minute.Thermal PrinterThermal printer is another type of non-impact printer. It can only print output on a special heat sensitive waxy paper (waxy means polish or shine). The image of the output is created on the waxy paper by burning dots on it. For colored output, colored waxy sheets are used.Introduction of Computer (Civil Engineering Department)34OUTPUT DEVICESPlottersA plotter is a special output device. It is used for printing architectural drawing, maps, graphs and charts. A plotter is typically used to print large-format graphs or maps such as construction maps or engineering drawings. Plotter is normally very slow output device. It works on the principle of holding a pen in hand and moving it on paper for drawing lines.Flatbed PlotterDrum PlotterIntroduction of Computer (Civil Engineering Department)35PLOTTERSIntroduction of Computer (Civil Engineering Department)Drum Plotter

Flatbed Plotter36OUTPUT DEVICESSpeakersSpeaker is used to receive audio output from the computer. The output received is in the form of sound. The sound is in the form of analog signals, but the data (i.e. sound) stored inside the computer in the form of digital signals . The speaker is connected to the computer through the port of sound card. The sound card converts the digital signals into analog forms. ProjectorsA projector is also an output device. With the help of a projector, we can display information on a large screen. The information may be printed on the papers or it may be an output of the computer. Usually, the output of the computer is display on a larger screen (on the wall).Projectors are mostly used in colleges and universities for teaching purposes. A teacher uses a projector in a classroom to deliver his lecture to the students. It is very easy, efficient and fast way to deliver lectures. It is also used in conferences and business meetings.Introduction of Computer (Civil Engineering Department)37SPEAKER & PROJECTORIntroduction of Computer (Civil Engineering Department)ProjectorSpeakers

38OUTPUT DEVICESFax MachinesA fax machine is also known as facsimile transmission machine. A fax machine is used to send and receive information through telephone line. The fax machine at sending side scans information printed on paper. It converts the information into signal and sends these signals over telephone lines to a fax machine at receiving side. The fax machine at receiving side receives information in the form of digital signals. It converts these signals into original form of the information and print on the paper.Introduction of Computer (Civil Engineering Department)

39CENTRAL PROCESSING UNIT (CPU)CPU is the most important component of the computer. It is also known as processor. It is considered as the brain of the computer. It processes input data according to the given instructions and converts it into useful information. It is further divided into two main components.

There are two parts of CPU.Arithmetic & Logical UnitsControl Units.Introduction of Computer (Civil Engineering Department)

40Arithmetic & Logical UnitArithmetic Logic Unit is an important component of computer. It performs the arithmetic and logical operations on the data. In arithmetic operations, ALU performs the addition, subtraction, multiplication and division.In logical operations, ALU compares the numerical data as well as alphabetic data. Control UnitThe control unit is the most important component of the CPU. It controls and coordinates the activities of all the other units of the computers. The control unit considered as the logical hub of the computer. It acts as a central nervous system for the other components of the computer.

Introduction of Computer (Civil Engineering Department)CENTRAL PROCESSING UNIT (CPU)41MEMORY UNITA component of the computer, which is used to store data and instructions is called memory. The personal computer contains a main memory. The main memory is the most important component of the computer. It is used to store data and instructions that are currently in use. Sometimes, main memory is also referred to as working area of the computer. The data and program instructions are loaded into main memory before executing. A computer cannot work without having main memory in it.

Basic Storage Units of Memory

BIT: The binary digit 1 or 0 is called a bit. The bit stands for binary digit. It is the basic unit for storing data in the computer memory.Introduction of Computer (Civil Engineering Department)42MEMORY UNITByte: A combination of 8-bits is called byte. One character takes one byte of memory. The storage capacity of the memory is expressed in terms of number of bytes.1 Nibble =4 bytes1 Byte=8 bits1 KB=1024 Bytes1 MB=1024 KB1 GB=1024 MB1 TB=1024 GBTypes of MemoriesIn computer, there are two types of memories.Volatile Memory (RAM)Non-Volatile Memory (ROM)

Introduction of Computer (Civil Engineering Department)43Volatile MemoryIt is a temporary memory. It loses its contents when computer is turned off. RAM or main memory is an example of volatile memory.Dynamic RAM (DRAM)Static RAM (SRAM)

Non-Volatile MemoryIt is a permanent memory. It does not lose its contents when computer is turned off. ROM is an example of non-volatile memory.PROMEPROMEEPROM

Introduction of Computer (Civil Engineering Department)MEMORY UNIT

44STORAGE DEVICESSecondary storage device is used to store data and programs permanently for later use. A large amount of data and programs can be stored into it. Its storage capacity is upto Gigabytes (GB) for personal computers. It is also referred to as backing storage. The application software and system software are stored on the secondary storage.

Magnetic DiskFloppy DiskZip DriveHard DiskCD/DVDMagnetic TapeUSBIntroduction of Computer (Civil Engineering Department)45STORAGE DEVICESIntroduction of Computer (Civil Engineering Department)Magnetic Disk

Hard Disk

Floppy DiskZip Drive46STORAGE DEVICESIntroduction of Computer (Civil Engineering Department)CD/DVDMagnetic TapeFloppy DiskUSB

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