1. The word computer comes from “compute” which means to calculate. Hence people usually consider a computer to be a calculating device. Computer is a processing device which processes raw data to produce meaningful data. Sheetal Chhabra

2. Characteristics of Computer 1.Accuracy : Computer performs every operation with equal and high accuracy. Errors can occur in a computer due to only human mistakes. 2.Repetitiveness: once the set of instruction are permanently fed to computer then it repeats the execution again and again as required. 3.Compactness : now a days the computers are very compact in size so they are portable and easy to handle. Sheetal Chhabra

3. 4. Diligence : Means the equal devotion at all time to its all work unlike human beings a computer is free from tiredness, lack of concentration. 5. Versatility : Computer is a versatile machine so it can perform any work ranging from simple to the complex task. 6. Automation: Automaticity means once a task is started computer can proceed on its own till its completion without any human intervention. 7. Speed: Speed is the most important characteristics because computer can perform any task much faster than human being. 8. Storage: Storage Capacity of computer is unlimited because of its main and secondary memory so it is capable of storing huge amounts of data. Sheetal Chhabra

4. Input – Output Devices: Input/output (I/O) devices provide the means of communication between the computer and outer world. Input devices are used to enter data from the outside world into primary storage and output devices supply the results of processing from the primary storage to the users. In short: Input device Reads data from outside world, Converts it into computer acceptable from and give it to computer system for further processing. Output device accepts the result produced by computer, converts it into human readable form and supply to outside world. Sheetal Chhabra

5. Role of input & Output Devices: Input Data Input DevicesCPUOutput Devices Result Of Processing Sheetal Chhabra

6. Input Devices Data Scanning Device Point & Draw Device Key Board Digitizer Electronic Card Device Voice Recognition Device Vision Based Device Sheetal Chhabra

7. Key Board : This Device is most commonly used input device today. It allow data entry into a computer system by pressing a set of keys which are neatly mounted on a key board, which is connected to the computer system. The most popular key board used today is the 101- keys key board. Sheetal Chhabra

8. Point & Draw Device:  It was realized that interacting with computers in text mode is cumbersome and time consuming hence a new type of interface called GUI was devised for interacting with computers. A GUI provides a screen full of graphic icons or menus to the users and allows user to make a rapid selection. Sheetal Chhabra

9. Mouse: Mouse is the most popular point & draw device. It has become a must have input device on personal computers and work station, which have a GUI based user interface. Mouse is a small hand held device, which can comfortably fit in a user’s palm. It rolls on a small bearing and has one or more buttons on the top when a user rolls the mouse across a flat surface the graphic cursor moves on the screen of video display terminal. Mouse displayed on screen as a variety of symbols. Sheetal Chhabra

10. Track Ball: A track ball is a pointing device which is similar to a mouse the ball is placed on the top along with buttons, to move the graphics cursor around the screen the ball is rolled with the fingers. A track ball requires less space than a mouse for operation. Track ball are commonly used in laptop. Three commonly used shapes of track ball are – a ball, a button and a square. Sheetal Chhabra

11. Joystick: A joystick is a pointing device, which works on the same principal as a track ball, which moves in a socket has a stick mounted on it. Instead of using fingers in case of a track ball, the user of a joystick moves the spherical ball with the help of the stick with his/ her hand. Sheetal Chhabra

12. Electric Pen: Another point & Draw device is an electric pen. In a pen based system you hold the pen in your hand and directly point with it on the screen to select menu items or icons or directly draw graphics on the screen with it or write with it on a special pad for direct input of the written information to the system. Sheetal Chhabra

13. Touch screen: Touch screen is the most simple, intuitive and easiest to learn of all input devices. A touch screen enables the users to choose from available options by simple touching with their finger the desired icon or menu item displayed on the computer screen. for example at an airport, railway station, ATM. Sheetal Chhabra

14.  Data scanning devices: Data scanning devices are input devices which are used for direct data scanning into the computer. They eliminate some of the duplication of human effort required to get data into the computer human beings do not have to manually enter the data. i) Image Scanner: Image scanner is an input device which translates paper documents into an electronic format which can be stored in a computer. Sheetal Chhabra

15. ii) Optical character recognition (OCR): OCR technology is used to overcome limitations of scanner such as internet the stored document as letters, numbers and special character and storage required for storing document. iii) Optical Mark Reader (OMR) : These scanners are capable of recognizing a prespecified type of mark made by pencil or pen the actual technique used by an OMR device for recognition of marks involves focusing a light on the page being scanned, and detecting the reflected light pattern from the marks. Pencil marks made with a soft lead pencil reflect the light enabling the reader to determine which responses are marked. Sheetal Chhabra

16. iv) Bar Code Reader: Bar codes represent alphanumeric data by a combination of adjacent vertical lines (bars) by verifying their width and the spacing between them they are particularly used for unique identification of all types of goods, books, tags etc. v) Magnetic-Ink Character Recognition: MICR is similar to OCR and is used by the banking industry for faster processing of the large value of cheques being handled every day by this industry, MICR use special type of cheque. The bank identification code (name, branch etc) Sheetal Chhabra

17. Digitizer : A digitizer is an input device, which is used for converting pictures, maps and drawing into digital from for storage in computers. Digitizers are commonly used in the area of Computer Aided Design (CAD) by architect and engineering to design cars, building, medical devices etc. Sheetal Chhabra

18. Electronic Card Device: Electronic card reader offer another means of direct data entry into computer electronic card are small plastic card having encoded data, which are appropriate for the application for which they are used. Electronic cards are often used by banks for use in Automatic Teller Machine (ATM) Sheetal Chhabra

19. Voice Recognition Devices : Voice recognition devices are input devices, which allow a person to input data to a computer system by speaking to it. Hence they make computers much easier to use for inputting data to a computer system by a person in situations where his/ her hands are busy. For example doctors in operation room can request certain information about a patient while operating fro authentication of a user by a computer system based on voice input. Sheetal Chhabra

20.  Vision Input System: It allows a computer to accept input just by seeing on object. A computer with a vision input device consists of a digital camera and follows following steps. i) The digital camera is focused on the input object to take a picture of the object. ii) Image of object in digital from so that it can be stored and interpreted by the computer. iii) The digitizer image of the object is matched against similarly formed pre-stored images in the computer’s image database. iv) Depending on weather a match is found or not, the system takes the appropriate action. For example Industrial robots are used for quality control in industries. Sheetal Chhabra

21. Output Devices: Plotters Monitor Printers Screen Image Projector Voice Response System Sheetal Chhabra

22. An output device is an electro mechanical device, which accept data from a computer and translates them into users suitable form. 1.) Monitor: Monitors are most popular output device. A monitor is usually associated with a keyboard and together they form a VDT (Video Display Terminal). The keyboard is used for input to the computer and the monitor is used to display the output from the computer. Two basic types of monitors are CRT (Cathode-Ray-Tube) & flat pannel. Sheetal Chhabra

23. 2.) Printer: Printers are most commonly used output device. They are classified into: a) Dot matrix Printers: They are char printer which print one char at a time. By dot matrix printers various types of characters can be formed as a pattern of dots. A dot matrix printers are impact printers because they print by hammering the pins on linked ribbon to leave ink impressions on the paper. Dot matrix printer speed usually ranging between 30 to 600 char per second. Sheetal Chhabra

24. b) Inkjet Printers: Inkjet printer are character printer which form char by spraying ink on the paper. The print head of an inkjet printer contains up to 64 tiny nozzles, to print a char. Inkjet Printers are non impact printers because they print by spraying ink on the paper. Inkjet printers are slower than Dot Matrix printers with speed usually ranging between 40 to 300 char per second. c) Drum Printers: Drum printers are line printers which print one line at a time it consist of a solid cylindrical drum with characters embossed on its surface in the form of circular bands. Drum printers are impact printers because they print by hammering the paper and the inked ribbon against the characters embossed on the drum. Speed of drum printer are in the range of 300 to 2000 lines per minute. Sheetal Chhabra

25. d) Chain/band Printers: Chain/band printers are line printers which print one line at a time. It consist of a metallic chain/band on which all the char of the char set supported by the printer are embossed. A standard char set may have 48,64 or 96 char. They are impact printer because they print by hammering the paper and the inked ribbon against the character embossed on the chain/band. e) Laser Printer: Laser printers are page printers which print one page at a time. The main components of a laser printer are a laser beam source, a multi-sided mirror, a photoconductive drum and a toner. Laser printer provide very high quality output. Laser printers are non impact printers because they do not have hammers on inked ribbon or paper. Low speed laser printers can print4 to 12 pages per minute. Very high speed laser printer can print 500 to 1000 pages per minute. Sheetal Chhabra

26. 3. Plotters: A special type of output device called plotters are ideal output device for architects, engineering, city planners and other who need to routinely generate high-precision hard copy graphic output of widely varying sizes. Two most commonly used types of plotters are drum plotter and flatbed plotter. In Drum Plotter the paper on which the design has to be made is placed over a drum, which can rotate in both clockwise & anti clockwise directions to produce vertical motion. The pen clamped in the holder can move left to right or right to left to produce horizontal motion. The movement of drum and the pens are controlled by the graph plotting program. A flatbed plotters plots a design or graphs on a sheet a paper, which that is spread and fixed over a rectangular flatbed tabel Sheetal Chhabra

27. 4. Screen image projector: Screen image projector is an output device, which is used to project information from a computer on to a large screen so that it can be simultaneously viewed by a large group of people. This output device is very useful for making presentations to a group of people with the direct use of computer before such an output device was available. Screen image projectors have become a common presentation equipment today. Sheetal Chhabra

28. Memory Primary Memory Secondary Memory Sheetal Chhabra

29. Primary Memory Core Memory Semiconductor Memory RAM ROM CACHE V RAM D RAM S RAM EPROM PROM EEPROM Sheetal Chhabra

30. Secondary Memory Magnetic MemoryOptical Memory Magnetic Tape Floppy Disk Magnetic Hard Disk Magnetic Drum Magnetic Bubble CD Rom DVD Sheetal Chhabra

31. Primary Memory (Main Memory): The memory that communicates directly with the CPU is called main memory. It consists of a set of storage cells known as register. It is of two type- 1. Core Memory 2. Semiconductor Memory Sheetal Chhabra

32. 1. Core Memory: It is made up of a large number of cells and each cell store one bit. It has a magnetic core which is in 0.4 to 0.8 mm diameter of ferromagnetic material. 2. Semiconductor Memory: Semiconductor memory consist of silicon rectangular array of memory cells. The memory cells are transistor or a circuit capable of storing charge and is used to store 1 bit of information. These are very fast. Semiconductor memory is very small in size but some problem with semiconductor memory generally these memory are volatile & costly. Sheetal Chhabra

33. RAM: An application in which data changes frequently calls for the use of a RAM. This memory consists of some integrated circuit chips (IC). RAM provide volatile storage. It is of two type: a)S RAM: Static RAM are those in which once a bit is stored in a memory cell it will remains as long as there is power available to the chip. b)D RAM: Dynamic RAM are those in which the bit loses in a very short period of time even through the power supply is on. Sheetal Chhabra

34. ROM: An application in which data does not change is the use of ROM. The content of ROM is fixed during manufacturing there is no write mod in ROM. PROM: (Programmable Read Only memory) An application in which the data does not change but the required data will not be available until programmed by the user. Sheetal Chhabra

35. b) EPROM (Erasable programmable read only memory) One disadvantage of PROM is that once it is programmed the contents are stored in that memory chip permanently it cannot be changed. If any mistake in programming the chip can not be corrected. The EPROM overcomes this difficulty EPROM is similar to ROM & PROM. C) EEPROM (Electronically EPROM): In this memory the erasing process is little simple to EPROM. Here memory is not removed from the computer but it is reprogrammed only for a limited number of times (i.e. 10000 times). Sheetal Chhabra

36. 3. Cache Memory: Cache memory is used between the CPU and main memory. Microprocessors operate at very high speed so due to this memory should be fast that’s why cache memory is used. Sheetal Chhabra

37. V RAM (VIDEO RAM): V RAM do any two work at a time like refreshing data and exchange data with the processor there is no need to complete one operation before starting the second. Sheetal Chhabra

38. Secondary Memory: Secondary memory (or secondary storage) is the slowest and cheapest form of memory. It cannot be processed directly by the CPU. It must first be copied into primary storage (also known as RAM). Secondary memory devices include magnetic disks like hard drives and floppy disks; optical disks such as CDs and magnetic tapes, which were the first forms of secondary memory. In modern computers, hard disk drives are usually used as secondary storage. Sheetal Chhabra

39. Magnetic tape is a medium for magnetic recording generally consisting of a thin magnetizable coating on a long and narrow strip of plastic. Nearly all recording tape is of this type, whether used for recording audio or video or for computer data storage. It was originally developed in Germany, based on the concept of magnetic wire recording. Devices that record and play back audio and video using magnetic tape are generally called tape recorders and video tape recorders respectively. A device that stores computer data on magnetic tape can be called a tape drive, a tape unit, or a streamer. Magnetic tape revolutionized the broadcast and recording industries. In an age when all radio (and later television) was live, it allowed programming to be prerecorded. In a time when gramophone records were recorded in one take, it allowed recordings to be created in multiple stages and easily mixed and edited with little loss in quality between generations. It is also one of the key enabling technologies in the development of modern computers. Magnetic tape allowed massive amounts of data to be stored in computers for long periods of time and to be rapidly accessed when needed Sheetal Chhabra

40. A floppy disk is a data storage medium that is composed of a disk of thin, flexible ("floppy") magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive," which is another term for a (non removable) type of hard disk drive. Invented by IBM, floppy disks in 8-inch (200 mm), 5¼-inch (133.35 mm), and 3½-inch (90 mm) formats enjoyed many years as a popular and ubiquitous form of data storage and exchange, from the mid- 1970s to the late 1990s Sheetal Chhabra

41. HDDs record data by magnetizing ferromagnetic material directionally, to represent either a 0 or a 1 binary digit. They read the data back by detecting the magnetization of the material. A typical HDD design consists of a spindle that holds one or more flat circular disks called platters, onto which the data is recorded. The platters are made from a non- magnetic material, usually aluminum alloy or glass, and are coated with a thin layer of magnetic material, typically 10-20 nm in thickness with an outer layer of carbon for protection. Older disks used iron(III) oxide as the magnetic material, but current disks use a cobalt-based alloy Sheetal Chhabra

42. Drum memory is a magnetic data storage device and was an early form of computer memory widely used in the 1950s and into the 1960s, invented by Gustav Tauschek in 1932 in Austria. For many machines, a drum formed the main working memory of the machine, with data and programs being loaded on to or off the drum using media such as paper tape or punch cards. Drums were so commonly used for the main working memory that these computers were often referred to as drum machines. Drums were later replaced as the main working memory by memory such as core memory and a variety of other systems which were faster as they had no moving parts, and which lasted until semiconductor memory entered the scene. A drum is a large metal cylinder that is coated on the outside surface with a ferromagnetic recording material. It could be considered the precursor to the hard disk platter, but in the form of a drum rather than a flat disk. A row of read-write heads runs along the long axis of the drum, one for each track. Sheetal Chhabra

43. Bubble memory is a type of non-volatile computer memory that uses a thin film of a magnetic material to hold small magnetized areas, known as bubbles or domains, each of which stores one bit of data. Bubble memory started out as a promising technology in the 1970s, but failed commercially as hard disk prices fell rapidly in the 1980s. Sheetal Chhabra

44. DVD, also known as Digital Versatile Disc or Digital Video Disc, is an optical disc storage media format, and was founded in 1995. Its main uses are video and data storage. DVDs are of the same dimensions as compact discs (CDs), but store more than six times as much data. Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM (read only memory) has data that can only be read and not written; DVD-R and DVD+R (recordable) can record data only once, and then function as a DVD-ROM; DVD-RW (re-writable), DVD+RW, and DVD-RAM (random access memory) can both record and erase data multiple times. The wavelength used by standard DVD lasers is 650 nm thus, the light has a red color. Sheetal Chhabra

45. CD-ROM "compact disc read-only memory") (pronounced /si di rom/) is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback, the 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data. CD-ROMs are popularly used to distribute computer software, including games and multimedia applications, though any data can be stored (up to the capacity limit of a disc). Some CDs hold both computer data and audio with the latter capable of being played on a CD player Sheetal Chhabra

46. THANKS

47. Software System Software Application Software Sheetal Chhabra

48. Software: Computer can perform only those works which are instructed by us. For a particular task, set of instruction are required. These set of instruction are call Sheetal Chhabra

49. System Software: The software which is specially designed to conduct and control all the hardware activities of computer as well as for interfacing between the hardware and the application programs to perform various information processing task is system software. System Software are classified into 3 category: 1. System management Programs : At the time of execution of various information processing jobs for example operating system, Operating environment, DBMS 2. System support programs : Different services which are provided by computer manage by these programs. e.g. system utilities, Security. Sheetal Chhabra

50. Application Software : These programs are designed to fulfill the information processing needs of end users or for some specific application. They are divided into two types- A) General Purpose Application B) Special Purpose Application. Sheetal Chhabra

51. General Purpose Application : They fulfill the basic information processing needs of end users related to home, education, business, scientific and many other purpose e.g. 1) Word Processing 2) Electronic Spread sheet 3)Database Managers 4) Telecommunication graphics. Sheetal Chhabra

52. Special Purpose Application : These programs are specially designed to handle a specific application task. e.g. 1) Commercial Programs – Accounting, Marketing, Production, Finance. 2) Scientific & Research Application Programs – Nature, Natural Life, Social Life, Engineering, Mathematics. 3) Arts & designing Application Programs Graphic & pictorial works. 4) Educational Application – Educational & Tutorial work. 5)Medical Application Programs. Sheetal Chhabra

53. Compiler : A high level language program must be converted into its equivalent machine language program before it can be executed on the computer. This translation is done with the help of a translator program which is known as compiler. A compiler can translate only those source program, which have been written in the language for which the compiler is meant. For e.g. C compiler is only capable of translating source program written in C. High Level Language Program Compiler Machine Language Program Input Output Sheetal Chhabra

54. Interpreter : An interpreter is another type of translator, which is used for translating program written in high level language. It takes one statement of a high-level language program & translates it into machine language instruction & then immediately executes the resulting machine language instructions. The input to an interpreter is the source program but unlike a compiler its output is the result of program execution, instead of an object program. High Level Language Program InterpreterResult of Program Input Output Sheetal Chhabra

55. As compared to compilers, interpreters are easier to write. They also required less memory space for execution than compilers. The main advantage of interpreters over compilers is that a syntax error in a program is detected and brought to the attention of the programmer. Sheetal Chhabra

56. Assembler : A computer can directly execute only machine language program, which use number for representing instructions and storage location. Hence assembly language program must be converted into its equivalent machine language program before it can be executed on the computer this translation is done with translation program which is known as assembler. It is a system software. Assembly Language Program Assembler Machine Language Program Input Output Sheetal Chhabra

57. Computer Languages: If you are instructing a person to do something then you have to say in language which is understood by that person. Similarly computer executes your task which is also in language computer languages are broadly classified into two: 1. Low Level Languages 2. High Level Languages Sheetal Chhabra

58. Low Level Languages Machine Lang Assembly Lang. High Level Language Procedural Oriented Lang. Problem Oriented Lang. Natural Language Sheetal Chhabra

59. Low Level Languages: Each & Every statement is directly translated into a single machine code in a language is called low level language. a) Machine Language: A language which uses the symbol of operating system and is for its complete operation codes is called machine language. Machine language is difficult to user but fast to execute. b) Assembly Language : Assembly language solve problem of machine language for solving this problem some alphanumeric symbols have been developed is called mnemonics such as ADD, SUM, MOV etc. Sheetal Chhabra

60. High level Language: The low level languages are machine dependent and closely related to the structure of computer. HLL developed to overcome all the above difficulties and it is combination of English and Mathematics. a) Procedural Languages: All the general purpose programming languages which are able to solve a variety of problems are called procedural oriented languages. These languages are also called 3 GL. b) Problem Oriented Languages: 4 GL designed to solve specific problems or develop specific applications by enabling us to describe what we want rather than step-by-step procedures. Sheetal Chhabra

61. C) Natural / AI language : Natural / AI languages are still in the development stage. The term AI artificial intelligence was first coined by John Mc Cathy during 70s. AI is defined as human intelligence on machine so human use the right piece of knowledge at right place as the system capable of planning & executing the right task at the right time. Sheetal Chhabra

62. Generation of Languages First GLSecond GLThird GLFourth GL Sheetal Chhabra

63. First Generation Languages: First generation languages (1940-50) was called low level or machine language. It was machine oriented. It consists 1 & 0 of binary code. It needed technical programmer to work. It was difficult to learn, read & write. Second Generation Languages: Second generation languages (1950-60) was assembly language. It used 0 & 1 and mnemonics like ADD, SUM, MOV etc. It was symbolic language. It was designed for INTEL (IBM) microprocessor. This languages need translator called Assembler. Due to alphanumeric abbreviations it is easier to remember. In terms of programmer’s time cost was very much. It was also used in system software. Sheetal Chhabra

64. Third GL : Third GL(1960-70) was known as HLL. It was English like language. It was machine independent language translators like interpreter, compiler are used. It was intended for use by professionals, programmers. Still ordinary user have some problem in use. It is better than 2 GL. Fourth GL : fourth GL (1970-80) was known as improved HLL. It was also machine independent language. Compiler & interpreter translator are used. It was also intended for use by professionals. End users have ease to use these languages. It was easy to learn, read & write. These languages are database oriented. Sheetal Chhabra

65. Operating System It is a soul of computer and without operating system computer is a dead machine. An OS is a master control program that runs the computer and acts as a scheduler. It controls the flow of signals from the various parts of the computer. It is the first program loaded into the computer’s memory. It sets the standards for the application programs that run it. All programs must be written to “talk to” the OS. Sheetal Chhabra

66. OS Application of OS Sheetal Chhabra

67. Application of OS It is a set of program by which we regulate all the activity and functions of computer. 1.Memory Management:- It allocates the primary and secondary memory to any data or programs. 2.Processor Management:- It assigns all the instruction and programs to the processor for their execution. 3.File Mgmt:- It stores any data and programs within a file and this file can be manipulated by so many ways. 4.I / O Mgmt:- It assigns and provides the jobs to the relevant input / output devices. 5.Security Mgmt:- It provides the security to stored data from users. Sheetal Chhabra

68. Application of OS 6. Integrity Mgmt:- It maintains the data and programs as an integrated form i.e. data never interfere with each other. 7. Translate Mgmt:- It works as a translator between users commands and hardware. 8. Communication Mgmt:- It provides the communication between the computer and user or computer to computer. 9. Process Mgmt:- It provides the different types of facilities of process like multiprogramming, multi-user, multi tasking etc. Sheetal Chhabra

69. Features of windows OS Microsoft upgrade for users of Windows 95 and earlier versions of Microsoft Windows OS. Windows include following features: A web aware user interface that allows web like views of local resources. Integrated Internet software including MS IE, Outlook express etc. Improved networking support with a faster TCP / IP protocol. support for (File Allocation Table) FAT – 32 drives and a FAT – 32 conversion utility. Support for Digital Versatile Disk (DVD). Support for multiple monitor and single computer. Support Universal Serial Bus (USB) and Infrared wireless connectivity. Built in Remote Access Service (RAS) for remote dialup. HTML based online Help. Sheetal Chhabra

70. UNIX OS UNIX is a multi-user time sharing operating system. Although it can be used on a wide variety of computers ranging from notebook computers to super computers. It is especially prevalent on Sun Microsystems, Hewlett- Packard, IBM. Unix was developed in the yearly 1970’s at bell laboratories by Ritchie for a small computer. It was the first operating system to be written in a high level language. The normal practice until then was to use assembly language for writing operating system, due to which operating systems were system dependent. Sheetal Chhabra

71. Basic Commands of UNIX $pwd :- check current directory $cp:- copy files ($cp shy sheetal) $cd:- Change current directory. $rm:- use to remove files. $mv:- move files to another directory. $ls :- show file list. $cat :- show file content. $chmod:- change file permission. $sleep:- Delay command execution in a script. $kill:- To terminate a process. $who:- Users and their activities. Sheetal Chhabra