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1 COMPUTER FUNDAMENTALS. 2 Introduction to Computers The word computer comes from the word compute", which means, to calculate. Thereby, a computer is.

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Presentation on theme: "1 COMPUTER FUNDAMENTALS. 2 Introduction to Computers The word computer comes from the word compute", which means, to calculate. Thereby, a computer is."— Presentation transcript:


2 2 Introduction to Computers The word computer comes from the word compute", which means, to calculate. Thereby, a computer is a electronics device that can perform arithmetic operations at high speed. A computer is also called a data processor because it can store,process & retrieve data whenever required.

3 Introduction to Computers Software - Word, PowerPoint, Excel, etc. Fun stuff - Games, Photos, etc. Operating Systems – Microsoft, Unix 3

4 Data Processing 4

5 Characteristics of Computer Automatic Characteristics SpeedAccuracyNo IQDiligence 5


7 Basic organization of a computer system 7

8 Input Unit 8

9 Output Unit 9

10 Storage Unit 10

11 Types of Storage 11

12 12

13 Central Processing Unit 13

14 14 Memory Units Memory is divided into storage locations called memory cells. Associated with each memory location are: 1. Address - position of a cell in memory 2. Contents - info stored 14

15 15 Memory Units Everything is manipulated as 0s and 1s stored using two-state devices: switches, transistors, vacuum tubes. On/Off states easily compare to the binary numbering system, Base 2. On = 1, Off = 0 Binary Digit = Bit

16 16 Memory Units Bits are grouped into bytes ( 8 bits = 1 byte) Each Memory Cell is 1 byte Bytes are grouped into words (length is dependent on the machine) The computer handles data in multiples of bit chunks (bytes) Data stored in 1 byte

17 Memory Units MAIN MEMORY UNIT: Also called as Primary Memory unit. 2 most important are: RAM ROM They work in different ways and perform distinct functions. 17

18 RAM (Random Access Memory) 18

19 ROM (Read Only Memory) 19

20 Types of ROM 20

21 Types of ROM 21

22 Cache Memory 22

23 Classification of Computers Computers Generations Generation" in computer talk is a step in technology. It provides a framework for the growth of computer industry. Till today there are five computer generations: 23

24 24

25 25

26 26

27 27

28 Electronics Devices 28

29 Input Devices Also known as Peripheral devices. Used to enter data from the outside world into primary storage. For e.g.: Keyboard Mouse Electronic Pen Joystick Scanner,etc

30 Keyboard

31 Mouse Mouse is a point-and-draw device. Move in all directions. Electronic Pen Point-and-draw device Used to directly pt with it on the screen to select icons or to draw graphics on screen. Can write with it on a special pad for direct I/P of written information to a system.

32 Joystick Pointing Device. Moved forward,backward,left & right. Button on the top is provided for selection. USES: Commonly used for video games,for controlling industrial robots.

33 Scanner,etc.




37 OCR (Optical Character reader) l Used to recognize alphanumeric characters. l Reflected light converts into binary no. l Dark area absorb the light whereas light is reflected by lighted areas. l Reflected light falls on Photocells which provide binary data corresponding to dark and light areas. l A B C D E………………………….z 0 1 2………………………………………… { } % ? etc.

38 Monitor Printer Speaker Screen image projector,etc

39 Monitors are the most popular o/p device used for producing soft-copy of the o/p. Types of Monitor: CRT Monitor LCD Screens

40 CRT Monitors This acronym stands for Cathode Ray Tube Very widespread Cheap Good performance

41 CRT Monitors

42 The Shadow Mask

43 Working method of CRT monitor The back of the tube has a negatively charged cathode, so called electron gun. The electron gun shoots electrons down the tube and onto a positively charged screen. The screen is coated with a pattern of red, green and blue phosphor dots that will glow when struck by the electron stream. The three dots together make up a pixel.

44 LCD Screens LCD means Liquid Crystal display Good quality

45 How LCD works? There is a thin liquid cristal layer between a horizontal and a vertical filter. Thanks to an appropriate voltage liquid cristals get arranged and light can pass the filters. This light will appear on the screen. In color LCDs each individual pixel is divided into three cells, or subpixels, which are colored red, green, and blue. Each subpixel can be controlled independently to yield thousands or millions of possible colors for each pixel.

46 Printers A computer printer is a device that produces a hard copy of documents stored, usually on physical print media such as paper. Main types of Printers Dot matrix Inkjet Laser Drum,etc.

47 Dot Matrix Printer

48 Inkjet Printers



51 Laser Printers


53 Drum Printers They are Line printer coz it print one line at a time. Have a solid cylindrical drum with characters embossed on its surface in the form of a circular bands. Set of hammer mounted in front of the drum in such a manner that an inked ribbon & paper can b placed b/w the hammer & drum.

54 Drum Printers It can only print a pre-defined set of characters in a pre-defined style that is embossed on the drum. The drum would have to complete one full revolution to print each line. Drum printers are impact printers,hence they can b used to produce multiple copies by using carbon paper.

55 Drum Printers

56 Screen Image Projector



59 Magnetic Tape


61 Advantages of Magnetic Tape

62 Limitation of Magnetic Tape

63 Magnetic Disk




67 Magnetic Disk Access Time

68 Magnetic Disk

69 Floppy Disk

70 Data is recorded on disk in concentric circular bands called tracks Each track is divided into pie- shaped wedges called sectors.Two or more sectors combine to form a cluster.

71 Floppy Disk Most computers maintain on the disk a table with the sector and track locations of data. This table, the file allocation table (FAT), enables the computer to locate data easily.


73 Hard Disk

74 Zip/Bernoulli Disk

75 Disk Pack

76 Winchester Disk

77 Optical Disks

78 Optical Disks Storage organization

79 Types of Optical Disks

80 CD-R (WORM)

81 CD-RW

82 DVD

83 Optical Disks CD-ROMs: Compact Disc Read-Only Memory can store up to 6 Mega Bytes CD-R: Compact Recordable holds the same storage, it is recordable once. CD-RW: Compact Disc Re-Writeable are read and writable, but does not have the same capacity, because it uses some magnetic technology. DVDs: Digital Versatile Disc can hold up to 17 Giga Bytes. Used by the contents industries.




































119 OPERATING SYSTEM A program that acts as an intermediary between a user of a computer and the computer hardware. Operating system goals: Execute user programs and make solving user problems easier. Make the computer system convenient to use. Use the computer hardware in an efficient manner.

120 OPERATING SYSTEM OS is a resource allocator Manages all resources Decides between conflicting requests for efficient and fair resource use OS is a control program Controls execution of programs to prevent errors and improper use of the computer


122 Logical Architecture of a Computer System This operating system layers hides the details of the hardware from the programmer Provides the programmer with convenient interface.

123 Parameters for measuring system performance

124 Functions of OS Process Management Memory Management File Management Security Command Interpretation

125 Process Management A process (also called job) is a program in execution. Process Management manages the processes submitted to a system in a manner to minimize idle time of processors (CPUs,I/O processors,etc.)

126 Process Management mechanism in early computers

127 Multiprogramming

128 Uniprogramming

129 Multiprogramming System

130 Process state in multiprogramming

131 Multitasking Interleaved execution of multiple jobs (often referred to as task of same user)in a single-user system. Computer system used for multitasking is uniprocessor systems(having only one CPU)

132 Multiprocessing

133 Multiprocessing System

134 Time-Sharing Simultaneously interactive use of a computer system. Short period during which a user process gets to use CPU is known as TIME SLICE,TIME SLOT or QUANTUM. CPU is taken away from a running process when the allotted time slice expires.

135 Process State Diagram of Time-Sharing System

136 Advantages of Time-Sharing l Reduces CPU idle time. l Provides advantages of quick response time.

137 Memory Management l Keeps track of parts of memory in use and parts not in use. l Allocates memory to processes as needed and deallocates when no longer needed.

138 Uniprogramming Memory Model l Used in systems that process one job only at a time.

139 Multiprogramming Memory Model

140 Multiprogramming with fixed no. of memory partition

141 Multiprogramming with variable no. of memory partition


143 Virtual Memory

144 Virtual Memory Realization

145 File Management

146 File access Method

147 File Operation

148 File Extensions l.c c source program file. l.txt general text file. l.doc microsoft world document file. l.xls microsoft excel spreedsheet file.

149 Security l Deals with destruction and unauthorized access. Types of Security: l External Security : Deals with fire,floods etc. l Internal Security : Deals with user authentication, access control, cryptography mechanism.

150 Security

151 Command Interpretation


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