Bank _level 4 and 5

Knowledge on Computer/IT

Computer: - Computer is an electronic data processing device, which accepts and store data input, processes the data input and generates the output in a required format. All physical parts of the computer that we can touch or feel are known as hardware. Example keyboard, mouse, monitor etc. A group of program that a computer uses to perform specific task is called software. Example Mozilla Firefox, MS Paint etc. (विद्युतीय माध्यमबाट चल्ने Device लाई कम्प्युटर भनिन्छ । कम्प्युटर एक प्रकारको इलेक्ट्रोनिक यन्त हो जसले अत्यन्तै उच्च बेगमा प्रयोग कर्ताले दिएको  निर्देशनाअनुसार कार्य सम्पादन गरि नतिजा प्रस्तुत गर्न र डाटा भण्डार गर्न सक्छ ।

The computer system along with various hardware units and software that makes the computer function and performs the different task is collectively known as computer system.

Charles Babbage was considered to be the father of computing.

Alan Turing  father of modern computer science

Henry Edward Roberts the father of the modern personal computers

Characteristic of computer: -

High-speed (कार्य वेग):-Computer is a very high speed electronic device. It can perform any calculation in a few milliseconds. Computer can perform complex calculation at a high speed that human being may not be able to do. The following terms are used to describe the speed of computer.

कम्प्युटरले कुनै पनि काम अत्यन्तै तेज गतिमा गर्न सक्छ ।यसले एक सेकेन्डमा करोडौं निर्देशनहरु पालना गर्न सक्छ।  कुनै जटिल भन्दा जटिल गणितीय समस्या समाधान गर्न साधारण व्यक्तिलाई महिनौं लाग्न सक्छ तर कम्प्युरले केही क्षणमा नै ठीक परिमण निकाल्न सक्छ । आधुनिक कम्प्युटरको गति यति तेज छ कि यसले जस्तोसुकै कठिन समस्य पनि क्षणभरमै समाधान  गरिदिन सक्छ ।

Unit of Time	Parts of Second	Power of 10
Millisecond(ms)	1/1000  of second       (One-thousandth)	1x10-3
Microsecond(us)	1/1000000 of second   (one-millionth)	1x10-6
Nanosecond(ns)	1/1000000000 of second   (one-billionth)	1x10-9
Picoseconds(ps)	1/1000000000000 of second  (one-trillionth)	1x10-12
Femtosecond(fm)	1/1000000000000000 of second (one-quardrillion)	1x10-15

Accuracy (दुरुस्तता): - Even though the computer has great speed, computers are very accurate. Computer acts upon the data as per given instruction and then gives the desired output. So accuracy means if the data, instruction is correct and reliable then the output produced by the computer is also correct and reliable. This is known as garbage in garbage out (GIGO).

कम्प्युटरले काम गर्दा कहिल्यै पनि गल्ती गदैन । प्रयोगकर्ताले गतल प्रोग्राम वा गतल सूत्र वा गलतआदेश दिएमा मात्र गलत नतिजा दिन्छ, अन्यथा कम्प्युटरले शत प्रतिशत शुद्ध नतिजा दिन्छ ।

Storage capacity (डाटाभण्डार): -The physical space inside the computer where we can store huge amount of data is called storage. Example hard disk, CD-ROM, DVD-ROMs, magnetic tape etc.

कम्प्युटरले आफ्नो आन्तरिक वा बाह्य भण्डारमा करोडौं डाटा तथा सूचनाहरु भण्डारण गरिराख्छ जुन हामीले चाहेको बेला प्रयोग गर्न सक्छौ। कम्प्युटरको हाड डिस्क वा र्‍यामलाई आन्तरिक भण्डार भनिन्छ भने फ्लपी डिस्क, पेन-ड्राएभ, सिडिरोम, म्याग्नेटिक टेप इत्यादिलाई बाह्य भण्डारण भनिन्छ ।यो डाटा भण्डरण गर्ने ठाउँमा कति डाटा अट्छन् भन्ने बाइट एकाइको प्रयोग गरिन्छ ।

The storage capacity for a computer is measured in

Units डाटा भण्डारण एकाइ	Meaning (बाइट्स)	Power of 2
0 or 1	1 Bit
4 Bits	1 Nibble
8 Bits	1 Byte
1024 bytes	1 Kilobyte (KB)	210
1024 Kilobytes	1 Megabyte (MB)	220
1024 Megabyte	1 Gigabyte (GB)	230
1024 Gigabyte	1 Terabyte (TB)	240
1024 Terabyte	1 Petabyte (EB)	250
1024 Petabyte	1 Exabyte	260
1024 Exabyte	1 Zetabyte (ZB)	270
1024 Zetabyte	1 Yottabyte (YB)	280

Diligence(एकाग्रता): -A computer is capable of performing the task continuously in the same speed for a long time. The characteristic of computer makes it useful for repetitive job like process control and quality control.कम्प्युटरले एकैनासले चौबिस घण्टा काम गरिरहन सक्छ । कम्प्युटर काम गर्दा यति लगनशील हुन्छ कियसले कहिल्यै ढिलो गर्ने,गल्ती गर्ने तथा अल्छी गर्ने गदैन । कम्प्युटर दिइएको काम यसले एकैनासले धेरैपटक दोहोर्याइ गरिरहन्छ ।

Versatility(परिवर्तनशीलता): -Computers are versatile machine. Computers are being used in different areas for different propose like in office, home, banks etc. the capabilities of computer to perform different task and has a wide range of areas depending upon different program used in it known as versatility. कम्प्युटरले जुनसुकै कार्यहरु हिसाब गर्ने, लेख छाप्ने, रोग निरीक्षण गर्ने, वैज्ञानिक कार्य गर्ने, शिक्षक बनी पढाउने, बैकिङ्ग कार्य गर्ने,रिजल्ट तयार गरिदिने लगायत धेरै कामहरु गर्न सक्छ । त्यसैले कम्पयुटरल एउटा परिवर्तनशीलता भएको मेसिन हो ।

Automatic ( स्वचालन): - Computers are automatic machine because one started on a job they carry out the job without any human intervention until it is finished.

हामीले कम्प्युटरलाई एकपटक डाटा वा निर्देशनहरु दिएपछि यसले आफ्से आफ कार्यहरु गर्ने सक्छ ।

Reliability-A computer is a reliable machine. Modern electronic components have long lives. Computers are design to make maintenance easy.

Arithmetical and logical operations: -Computer can perform arithmetical and logical operations suchas additions, subtraction, multiplication, division, comparison etc.

Communications: - Today computer is mostly used to exchange messages or data through computer networks all over the world very quickly.

Limitation of computer

1.      No self-Intelligence: - Computer can do very complex and dangerous task which are impossible for human being. It works according to the give instruction only. It does not have any intelligence of its own.

2.      No thinking and Decision making power(IQ): - It cannot take any decision of its own, it does only those tasks which are already instructed to it in the form of program. It is we to decide what we want to do and in what sequences.

3.      No feeling: - A computer cannot feel anything as human. It does not have feelings or emotion, taste, knowledge and experience.  This it does not get tired even after long hours of works.

4.      No learning power: - Computer has no learning power. Once we give instruction to a computer how to perform a task. It cannot perform the same task if we do not give it any instruction for the next time.

Application areas of computers

1.      Office: - Important work performed in office such as preparation of letters, reports, copy of advertisement, publicity, contract, forms, notes etc. are efficiently performed by computer. Computer helps the user ion preparing, storing and retrieving information.

2.      Desktop publishing system: -All magazines, newspaper, books, comics are produced using computers. Software such as word-processing is used for text typing, dia for drawing, figure etc.

3.      Data Analysis: Software such as spreadsheet can be used to tabulate result, calculate number of students, average marks. One can prepare product sales, profit, invest from an organization. Computers are widely used for statistical data analysis.

4.      Computer Aided manufacturing (CAM): Computer is used to control the production of certain engineering products, chemical products etc. Example in a mechanical industry, designer used Auto CAD for designing the machines and machine parts. CAM system is used to automate the production such as quality control, measuring the size of the item during production, measuring packaging the item after production and many more.

5.      Graphics: Computers are being used to draw drawing, graphics and picture. Graphics packages such as MS paint, Adobe Photoshop, Coral Draw etc. are used for two and three dimension drawing.

6.      Database Management: Computers are extensively used to store and retrieve information. File are now stored in magnetic memory. There is no need of paper to store the information. Database management system not only stores the information but also does data analysis of information popular database management software are ORACLE, Sybase, SQL, MS ACCESS etc.

7.      Project management: A project management project used to plan, schedule and control man power, material and other resource needed to complete the project in schedule time period at a reasonable cost. Computer are used to plan, schedule and perform the detail analysis of the work done, in case of project delay, computer helps to increase the speed id time for completion.

8.      Communication: Computers are extensively used in sending and receiving information. The information transfer may take place either between two points or throughout a computer network that connects a number of computers or workstations. Different communication services such as Electronic mail (e-mail), teleconferencing or video conferencing, internet phone, bulletin board system (BBS), chatting, online banking, satellite communicant etc. are used for communication.

9.      Education: In educational institutions, computers are used as a teaching aid, information resource and research tools. When a computer is used as a teaching tool, it is referred to as Computer Assisted instructions (CAI). Internet technology provides several educational materials, online lectures and tutorials for students.

10.   Health and Medical field: Computer is widely used in hospital to help doctors in diagnosis, getting information on patients, diseases, treatment, drugs etc. Computer in hospital are used in different medical units such as ICU, ECG, operation theater, X-ray, recovery room, pathology etc. They are also used in administration and in keeping patient records.

11.   Reservation System: Computers store all information in connection with tickets reservation such as train /bus/aero plane number, station, distance, number of seats.

12.   Banking: - Computer in banking are used for different purpose such as general computations, transaction handling, record keeping, ledger maintenance, online services, ATM etc.

13.   Military:- The computers have played an increasingly important role in the military. The computers in the military have been adapted or designed to do a broad range of tasks, such as analyzing intelligence, organizing prudent data for military leaders, geospatial analysis, controlling smart weapons, or communications.

Classification of computes

On the basis of working principle: - On the basis of working principle, computers are categorized into three types-

Analog Computer (एनालग कम्प्युटर): -A computer in which problem variables are represented as continuous variable physical quantities such as temperature, electrical, mechanical or hydraulic quantities. Presley is an example of analog computer.

Characteristic

·        Analog computer measures the continuous physical variations such as pressure, temperature, voltage etc.

·        It generates analog signals

·        It has very low accuracy

·        It has high cost

·        It is used for special purpose

·        Re-programmed is not possible

·        E.g. Speedometer

भौतिक मानहरु जस्तै तापक्रम,चाप,भोल्टेज, करेन्ट इत्यादि नाप्न एनालग कम्प्युटरको प्रयोग गरिन्छ । एनालग कम्प्युटरहरु खासगरी कुनै विशोष कामका लागि बनाइएका हुन्छन् ।

Digital computer(डिजिटलकम्प्युटर): - A digital computer is an electronic computing machine that uses the binary digits (bits) 0 and 1 to represent all forms of information in digital form.

Characteristic

·        Digital computer processes discrete data such as number, letters etc.

·        It generates digital signal

·        It has high accuracy

·        It is used for general purpose

·        Re-programmed can be possible

·        E.g. IBM PC, IBM Compatible, Apple/Macintosh

बाइनेरी डिजिट (0 and 1)  मा आधारित कम्प्युटरहरुलाई डिजिटल कम्प्युटर भनिन्छ । हरेक डिजिटल कम्प्युटरहरुले सम्पूर्ण जानकारी (अक्षर,संख्या, चित्र) हरुलाई बाइनेरी नम्बरका रुपमा प्रतिनिधित्व गर्दछन् र ती जानकारीहरुलाइ अर्थमेटिक अपरेसनको प्रयोगमा प्रोसेसिङ गरी नतिजा निकालिदिन्छन । पर्सनल कम्प्युटर, ल्यापटप आदि डिजिटल कम्प्युटरका उदाहरणहरु हुन् ।

Hybrid computer(हाइब्रिड कम्प्युटर): - Computer that contains the features of analog computers is capable of inputting and outputting in both analog and digital signal. Example FMC, EICS.

Characteristic: -

·        Can process both continuous and digital data

·        It has capacity to convert one type of data into another

·        These are special purpose machine.

·        These computers normally have high cost।

एनालग र हाइब्रिड दुबै खालका काम गर्न सक्ने कम्प्युटरहरुलाई हाइब्रिड कम्प्युटर भनिन्छ । डाटाहरु  एनालबाट डिजिटलमा र डिजिटलबाट एनालगमा ल्याउन सक्ने क्षमता यस्ता कम्प्युटरहरुमा हुन्छ । यस्ता कम्प्युटरहरु हवाइजहादज,रकेट,अस्पताल, कारखाना, वैज्ञानिक कार्यशाला आदि जडान गरिएका हुन्छन् ।

On the basis of power and size

Super computer (सुपर कम्प्युटर): -Supercomputer is one of the fastest computer current available. Super computers are very expensive and are employed for specialized application that required immense amount of mathematical calculation. Example weather forecasting, scientific simulation, animated graphics, fluids dynamics calculation, nuclear emery research, electronic design and analysis of geological data. Example Cray-1, ETA10, Y-MP/C90 etc.

सुपर कम्प्युटर सबैभन्दा  शक्तिशाली कम्प्युटर हो। यसको साइज ठूलो हुन्छ र प्रोसेसिङ गति निकै बढी हुन्छ । यस्ता कम्प्युटरहरु खासगरी बैज्ञानिक अनुसन्धानहरुजस्तै न्युक्लियर फिसन, न्युक्लियर चेन रियाक्सन आदि कामका लागि प्रयोग गरिन्छ। CYBER 205, Cray-1, ETA10, Y-MP/C90 इत्यादि सुपर कम्प्युटरका उदाहरणहरु हुन् ।

Mainframe computers:-It is a general purpose computer designed for large scale data processing. This machine can handle word length of 32 to 64 bits having an execution speed of 100 to 200 MIPS hand having the memory size of 256 to 512 megabits (MB). Memory access time is of 123 nanoseconds; this computer can enter 100 to 200 data operator worked at the same time with a single CPU. Example IBM-1401, IBM-4300 seried, IC2950/10 etc. यो कम्प्युटर आयतको हिसाबले निकै ठूलो हुन्छ । यसले करीब १ हजारवर्ग फिट ठाउ लिन्छ । यो निकै शक्तिशाली र प्रोसेसिङ गति निकै बढी भएको कम्प्युटर हो । यस कम्प्युटरबाट एकैपटक ४००/५०० ओटा कम्प्युटर टर्मिनलमा डाटा इन्ट्री गर्न वा डाटा प्रोसेसिङ गर्न सकिन्छ । यस्या कम्प्युटरमा एकै समयमा सयौ मानिसहरुले कार्य गर्न सक्छन् । यसको मूल्य पनि निकै धेरै छ ।यसले सम्पूर्ण नेटवर्किङमा भाग लिन सक्छ। मेनफेम कम्प्युटरको प्रयोग जनगरणाना, औधोगिक गणना, कृषि गणना, कृषि गणना, परीक्षाको नतिजा प्रशोधन, भन्सार तथा पर्यटन  विभागका तथ्याङ्कहरु लगायतका ठूला-ठूला कार्यहरु गर्ने गरिन्छ । त्यस्तै मौसमको भनिष्यवाणी, स्टक विश्लेषण, आटोमोबाइल डिजाइन इत्यादि कार्यका लागि पनि मेनफेम कम्प्युटर प्रयोग गरिन्छ । IBM 140, ICL 2950/10, ACOS इत्यादि मेनफ्रेम कम्प्युटरका उदाहरणहरु हुन ।

Minicomputer: -Mimi Computer is a general purpose computer which is comparatively small and less expensive than a mainframe computer. It has slower operating speed, smaller vacuum storage, limited hardware and lesser memory capacity compared to a install and operated Mini computers are relatively easy to install and operate in a multi-terminal device, These have a memory of 64 to 256 MB; access time being 75 to 100 nanoseconds an can handle 16 to 32 bit word length. Example IBM AS1400, IBM/B60, HP-900, PDP-II, VAX-11/780, plesley etc. यस कम्प्युटरहरु मेनफ्रेम कम्प्युटरभन्दा साना र माइक्रो कम्प्युटरभन्दा टूलो हुन्छन । यी कम्प्युटरहरु सुपर कम्प्युटर र मेनफेम कम्प्युटरभन्दा कम शक्तिशाली र माइक्रो कम्प्युटरभन्दा बढी शक्तिशाली हुन्छन् । यस कम्प्युटरमा पनि सयौ टर्मिनलहरु जोडेर यसबाट काम गराउन सकिन्छ । यी कम्प्युटरहरु विशेष गरी डाटा प्रोसेसिङ,प्रो ग्रामिङ र डेस्कटप पब्लसिङजस्ता कार्यहरुमा प्रयोग गरिन्छ ।नेपाल टेलिकम, बैक, राष्ट्रिय वाणिज्य बैक, कृषि विकास बैक, वायुसेवा निगम लगायतका ठागहरुमा मिनी कम्प्युटरको प्रयोग गरिएको पाइन्छ । IBMPC, IBMXT, IBMAT इत्यादि मिनी कम्प्युटर उदाहरणहरु हुन् ।

Workstation: - Work station is a computer used for engineering application (CAD/CAM). Desktop publishing, software development which require a moderate amount of computing power and relatively high quality graphics capabilities.

यो आयतनको हिसाबले सबैभन्दा सानो कम्प्युटर हो । यो कम्प्युटर माइक्रो चिप्स प्रयोग गरेर बनाइएको हुनाले यसको नाम माइक्रोकम्प्युटर राखिएको हो ।माइक्रोकम्प्युटरलाई पर्सनल कम्प्युटर वा होम कम्प्युटर पनि भन्ने गरिन्छ। माइक्रोकम्प्युटरहरु मुख्य गरी घर तथा अफिसहरुमा प्रयोग गरिन्छ । माइक्रो कम्प्युटरको प्रयोग व्यापार, व्यवसाय, शिक्षा, सञ्चार, डेस्कटप, ग्राफिक डिजाइनिङ, डाटा प्रोसेसिङ आदि गरिन्छ ।

Personal computers: - A personal computer is a single user oriented and general purpose micro computer processing system that can execute the program instruction to perform a wide variety task. a person computer contains a monitor keyboard, mouse etc. Several high level languages can be used in personal computer, popular operating system such as MSDOS, Microsoft Windows, Windows NT, Linux, and UNIX are used in this type of computer system.

Function of computer

Input or The computer accepts input (इनपुट युनिट) -The process of entering data and program in to the computer system. An input device includes keyboard, mouse, scanner etc. Input includes words and symbols in a document, number for calculation, instruction for completing a process, picture and so on. प्रकयोगकर्ताले कम्प्युटभित्र प्रसेसिङलका लागि डाटा तथा निर्देशनहरु पठाउन प्रयोग गरिने एकाइ वा डिभाइसलाई इनपुट युनिट भनिन्छ । इनपुट युनिटअन्तर्गत माउस, किबोड, ज्वाइस्टिक्टक,  स्क्यानर, डिजिटल क्यामेरा,  अप्टिकल क्यारेक्टर रीडर, अप्टिकाल मार्क रीडर, वेब क्यामम, लाइट पेन, ट्रयाक बल, टच स्क्रिन  लगाएत धेरै डिभाइसहरु पर्दछन् ।

Keyboard (किबोर्ड) -A keyboard is used to enter data directly into computer, while typing on a computer using keyboard, you will notice a flashing line on the screen which is called curser. When a key on the keyboard is pressed that characteris displayed at the point where the curser is flashing and cursor moves one position forward. A keyboard contains alphabets, digits, special character and function keys. The most commonly used keyboard is QWERTY keyboard which contain 104 key including 12 function keys. किबोर्ड एउटा प्राथमिक इन्पुट यन्त्र हो । कम्पयुटरमा निर्देशन दिन या प्रोग्राम तयार पार्न किबोर्ड प्रयोग गरिन्छ । किवोर्डमा अक्षर, अंक, सिम्बनोललगायतका अन्य विभिन्नन 'कि"हरु हुन्छन् । किबोर्डमा १०४ वटासम्म किहरु रहन सक्छन । किबोर्ड ए देखी जेड सम्मा २६ वटा अक्षर, ० देखि ९ सम्म १० वटा अंक, गणितीय संकेत र चिन्हहरु, एफ१ देखि एफ१२ सम्मका फङ्सन की क्याप्सलक, सिफ्ट, डेलकी, व्याक स्पेस कि, इन्सर्ट कि, इन्टर कि, नम लक कि, करसर कि जस्ता किहरु रहेका हुन्छन् । कि बोर्डलाई प्राय ५ पीन केबलद्धारा सिष्टम युनिटमा जोडिएको हुन्छ

Mouse (माउस):-It is a hand held device that points on the screen when moved across a flat surface. A mouse has one or more buttons on the surface to make selection from the menus on the screen or the for control purpose. माउस किबोर्डपछिको एक महत्त्वपूर्ण इनपुट डिभाइस हो । यो प्रायः मुसा आकारको हुन्छ । यसको सीधा सम्बन्ध कम्प्युटरको स्क्रिनसँग रहेको हुन्छ । धेरैजसो माउसहरुमा दुईवटा बटन रहेको हुन्छन् । बायाँ र दायाँ बटन । यिनै बटनहरुलाई प्रेस गरेर कुनै सूचना वा डाटाहरुलाई कम्प्युटरको प्रोसेसरमा पठाउन सकिनछ । विषेषगरी विनडोज प्याकेज, ग्राफिकल प्याकेज तथा अन्य एप्लिकेशन प्याकेजहरुमा यो उपयोगी हुन्छ। कुनै माउसको बीचमा स्क्रल बटन रहेको हुन्छ । जसबाट पेजलाई तलमाथी लैजान सकिन्छ ।

Scanner: -Scanner is an input device which is capable of entering information directly into the computer without typing any information or data. A scanner scans an image and transform the image to the code used by a computer.

Light Pen(लाइटपेन): -A light pen is a pointing device. it is a photosensitive pen lighting device, which is capable of sensing a position on the screen when its tip touches the screen. When its tip is moved over the screen its photo cell sensing system detects the light coming from the screen and the corresponding signals are sent to the processor.

लाइटपेन एउटा प्वाइन्टिङ साधन हो । लाइट पेनले कम्प्युटरको मनिटरमा छोएर कुनै पनि आकार कोर्न, चित्र बनाउन वा कुनै शब्द लेख्न सकिन्छ । लाइटरपेनलाई केवलद्धार कम्प्युटरमा जोडिएको हुन्छ र हेर्दा पेन जस्तै हुन्छ ।

Joystick(जोयस्टिक):-Joystick is a screen point device. A joy consists of vertical stick and spring. The spring is used to return the joystick to its central position. The stick be moved in any direction, left, right, up and down and four diagonally directions and the switch detects in which direction the stick is being moved. It is used mostly in video games, flight simulation for training pilots. जोयस्टिकको प्रयोग गरेर कम्प्युटरमा विभिन्न खेलहरु खेल्न सकिन्छ । जोयस्टिकमा एउटा ह्याण्डल रहेको हुन्छ, जसलाई समातेर यताउता घुमाएर स्क्रिनमा कुनै विशेष बस्तुको चलालाई बदलेर कुनै पनि खेलहरु खेल्न सकिन्छ ।

Touchpad: - Touch pad is a touch sensitive pad that is used as a pointing input device. We can point the objects on the screen and give command to the computer by putting out fingers on the touch pad. The touch pad also used with portable computers such as laptops, palmtops, notebooks etc.

Bar code reader (BCR): - Data coded in the form of small lines(bars) are known as bar codes. Bar code data represent the alpha-numeric data by a combination of adjacent vertical lines(bars) by varying their width and spacing between them. They are used for unique identification of all types of goods, books, postal packages etc. A bar code reader is a device used for reading bar coded data. It scans a bar code in image and converts it into alpha-numeric values. A bar code reader uses laser beam scanning technology.

Optical character reader(OCR): -:  An OCR detects alphanumeric characters printed or type written on papers. The reading is done by the light scanning techniques in which each character is illuminated by a light source and the reflected images of the characters are analyzed in terms of light and dark pattern produced.

OMR(Optical Mark Reader)- an OMR is being used to read answer sheet by means of light. The change in the amount of reflection light is used to detect the presence of mark.

Magnetic Ink Character Reader (MICR):- This system uses a special ink to print characters. These characters can be detected by a specific magnetic device. This system is widely used in banks for processing cheque. Cheque numbers are printed with the ink containing magnetic particle of iron oxide. The MICR read the magnetic pattern of the written characters. To identify the characters, these patterns are compares d with the optical patterns stored in the memory.

Digitizer: - A digitizer is an input device used for converting pictures, maps and drawing into digital form for storage in computer. A digitizer consists of a digitizing tablet also called graphic tablets associated with a stylus. A digitizer tablet is a flat surface that contains hundreds of fine coppers wires forming a grid. Digitizers are used commonly in the area of computer aided design (CAD) by architecture and engineers to design cars, buildings, medical devices, robots etc. They are also used in the area of Geographical Information system (GIS).

Speech recognition Device: - In speech recognition device, the voice signals are sent to the processor for processing, the signal pattern is compared with the patterns already stored in the memory. A word is recognizing only when a choice match is found and then the computer gives a corresponding output.

Digital camera: - A digital camera is a camera that takes video or photographs and input to the computer in the digital format. At first, the photographs are stores in the camera's memory and then transferred to a computer through a cable.

Microphone: - A microphone is an input device which is also called a MIC that is used to input voice or sound into the computer. We can record speech, songs etc. in the computer using microphone. A computer stores recorded voice and sound in the digital format.

Trace ball: - The trackball is also a pointing device like mouse which consists of a movable ball in a socket. The ball can be rolled by user's finger or palm to move the pointer on the screen. Trackballs are mostly used in portable computers such as laptops, palmtops, notebooks etc.

Web camera: - A web camera is an input device with special camera which is used to take photo or videos and sends to the computer as input for processing. This device is mainly used in internet chatting and video conversion

Touch screen: -A touch screen is a computer display screen that serves as an input device. When a touch screen is touched by a finger or stylus, it registers the event and sends it to a controller for processing.A touch screen may contain pictures or words that the user can touch to interact with the device.

Switch input device: - Switch systems are a combination of hardware used with appropriate software that scans through options on the computer screen allowing a user to trigger the switch when the option they wish to choose is highlighted on the screen.

Switch devices may replace the use of a keyboard and/or mouse. Switches enable an individual who has reliable control of one or more movements to control any electronic device which is equipped with an appropriate switch interface/connection.

Switches can include:

·        wireless devices

·        foot plate

·        mechanical switches

·        gel pressure switches

·        electronic or sensor switches

The computer stores data: -The process of saving data and instruction permanently is known as storage. Storage device includes Hard disk, Tapes, CD/DVDs, pen drive, floppy disk etc.

Floppy disk (फल्पी डिस्क) -Floppy disk is a magnetic storage device. It is also called magnetic disk. It is a thin plastic disk coated with magnetic material. This plastic disk protected by a hard outer cover which is rectangular in shape, we can read data from floppy disk and write into it. A floppy disk driver is needed to read data from floppy disk and write onto it. The floppy disk is used to transfer small amount of data from one computer to another. The most common size of floppy disk is 3.5" in diameter and it has a storage capacity of 1.44 MB (Megabyte). फ्लपी डिस्क प्लास्टिकको खोलले ढाकिएको आइरन अक्साइड दलिएको वृताकार चुम्बकीय डिस्क हो । यो डिस्क एउटा कम्प्युटरबाट अर्को कम्प्युटरमा डाटाहरु सार्न निकै उपयोगी हुन्छ ।यसले करीव ३६० किलोबाइट देखि १.४४ मेगाबाइटसम्म डाटा स्टोरेज गर्न सक्छ ।

Size and type	Speed	Track	Sector	Capacity
5.25"(Double Density)	300 rpm	40	9	360KB
5.25"(High Density)	360 rpm	80	15	1.2MB
3.5"(Double Density)	300 rpm	80	9	720KB
3.5"(High  Density)	300 rpm	80	18	1.44MB
5.25"(Extra HD)	300 rpm	80	36	2.88 MB

Hard disk (हार्ड डिस्क): - Hard disk is the most commonly used secondary storage device in the personal computer. It is also called the magnetic disk, HDD, hard drive, fixed drive or fixed disk.  It is the main and largest data storage in the computer. It can store a large amount of data and information permanently. It contains one or more metal platters mounted on a central spindle. Each platter is coated on both sides with magnetic material. Both surfaces of each disk or platter are used to store information except for the top and bottom platters.  The hard disk and drive is a single unit. It includes the hard disk, the motor that rotates the platters. Each platters has two read/ write heads, one heads, one for each side. The hard disk has also arms that move the read / write heads to the proper location on the patters to read or write data. The entire is enclosed in an airtight sealed case. The storage capacity of hard disk range available are 200 GB, 300 GB, 500 GB, 1 TB, 2 TB, 4 TB etc.

हार्ड डिस्क कम्प्युटरको डाटा भण्डारण गर्ने प्रमुख साधन वा उपकरण हो ।  यसको बनावट कडा एवं मजबुत हुन्छ । हार्ड डिस्कमा धेरै डाटाहरुलाई भन्डारण गर्ने क्षमता हुन्छ । कम्प्युटरका सम्पूर्ण सफ्टवेयरहरु र ती सफ्टवेरबाट बनाइएका सम्पूर्ण डकुमेन्टहरु हार्ड डिस्क मै भण्डारण गरी राखिन्छ । हार्ड डिस्कलाई कम्प्युटरभित्र नै प्राय स्थानीयरुपमा राखिएको हुन्छ । यो मदरबोर्डमा जोडिएको हुँदेन । त्यसकारण यसलाई बाह्य मेमोरी पनि भनिन्छ ।  हार्ड डिस्क 200 GB, 300 GB, 500 GB, 1 TB, 2 TB, 4 TB क्षमता सम्माका  डाटाहरु स्टोर गर्न सकिन्छ ।

Advantages of hard disk

1.      Larger storage capacity

2.      Stores and retrieves data much faster than floppy disk or CD-ROM.

3.      Usually fixed inside the computer so cannot get mislaid.

4.      It is more durable and reliable than a floppy disk or other storage media.

5.      Cheap on a cost per megabyte compared to other storage media

6.      Hard sis can be replaced and upgraded as necessary.

Disadvantages

1.      Hard disk eventually fail which stopes the computer from working.

2.      Regular head crashed can damage the surface of the disk, leading to loss of data in that sector.

3.      The disk is fixed inside the computer and cannot easily be transferred to another computer.

The computer processing the data: - The task of performing operation like arithmetic and logical operation is called processing.

The computer produces output (आउटपुट युनिट): - The process of producing results from the data for getting useful information. Output device includes printer, monitor, speaker etc.कम्प्युटरले डाटाहरु प्रसोधन गरी सकेपछिको रिजल्ट दिने डिभासहरुलाई आउपुट डिभास वा युनिट भनिन्छ । नतिजा देखाउने, छाप्ने वा आवाज निकाल्ने अङ्गलाई आउटपुट डिभाससेस भनिन्छ । यी आउटपुट डिभासहरुले दिने आउटपुट सफ्ट आउटपुट र हार्ड आउटपुट गरी मुख्य दुई प्रकारका हुन्छन् ।

Soft-copy output: - A soft copy is an electronic copy of some type of data, such as a file viewed on a computer's display. They are temporary in nature. Example monitor.

Monitor(मनिटर): - Monitors are the most popular output device used today for producing softcopy output. हेर्दा टेलिभिजनको पर्दाजस्तो देखिने महत्वपुर्ण आउटपुट डिभासलाई मनिटर भनिन्छ । मनिटरको सहायताबाट कम्प्युटरबाट प्राप्त भएका परिणामहरु स्क्रिमना पढ्न वा देख्न सकिन्छ । यसलाई स्क्रिन वा  Visual Display Unit भनिन्छ। कम्प्युटरमा प्रोसेसिङ भैसकेपछि सम्पूर्ण रिजल्ट हर्नका लागि मनिटरे नै चाहिन्छ। यसकको सहयोद्वारा कम्प्युटरमा दिइने सूचना वा डाटाहरु सही रुपमा छ वा छैन भन्ने प्रष्टसँग देखिन्छ ।

Monochrome monitors: -  Monochrome means information displayed in one color such as white, green, black, amber or gray on a different color usually black. These monitors are usually used to display text only.

Monochrome: - Monochrome means information displayed in one color such as white, green, blue, amber or gray on different color background usually black. These monitor are usually used to display text only.

Color monitors: - Color monitors are used to display output in different 16 colors to millions of colors. Color monitors are of three main types. They are CRT monitors, LCD monitors and LED monitors.

CRT monitors: - An electron beam is produced by the electron gun located at the back portion of the cathode ray tube, the electron beam is directed towards the front of the CRT screen. A coating of phosphor material is made on the inner surface of the screen. The phosphor emits light when it struck by the electron beam on the screen. This causes the visibility of the characters of graphics.

LCD monitor: - Liquid-crystal display (LCD) is a flat-panel display that uses the light-modulating properties of liquid crystals. Liquid crystals do not emit light directly, instead using a backlight or reflector to produce images in color. LCDs monitors are thinner, lighter and are used commonly with portable computer system like notebook. Laptops etc.

LED monitors: -LED monitor (Light Emitting Diode) or LED display is a flat screen, flat panel computer monitor or television which uses an array of light-emitting diodes as pixels for a video display.  It has a very short depth and is light in terms of weight. Their brightness allows them to be used outdoors where they are visible in the sun store signs and billboards.

Speaker(स्पिकर): - A speaker is an audio response device that produces audio output from the computer system, the output is temporary, soft copy output A speaker produces audio output by selection and appropriate audio from a set of prerecorded audio responses. स्पिकारले आवाजलाई आउटपुटको रुपमा कम्प्युटरबाट निस्कन्छ ।

3D audio: -3D audio effects are a group of sound effects that manipulate the sound produced by stereo speakers, surround-sound speakers, speaker-arrays, or headphones. This frequently involves the virtual placement of sound sources anywhere in three-dimensional space, including behind, above or below the listener.

Hard copy output: - A hard copy output is produced on a paper or some material that can be touched and carried for being shown to other, they are permanent in nature. Example printer, plotters etc.

1. Printer(प्रिन्टर) -Printer are the most popular output devices used today for hard-copy output. Thy provide information in a permanent readable form. They produce printed output of results, program and data. Printer are classified as impact and non-impact printers. कम्प्युटरबाट निस्किएको परिणमलाई काजगमा छाप्न प्रयोग गरिने आउटपुट डिभासलाई प्रिन्टर भनिन्छ । प्रिन्टरहरु विभिन्न प्रकारका हुन्छन् । तीमध्ये मुख्यरुपमा डट म्यट्रिक्स प्रिन्टर, डाइजेह्वील प्रिन्टर, इन्कजेट प्रिन्टर र लेजर प्रिन्टर पर्दछन् ।

a.      Impact printers: It uses electromechanical mechanism that causes hammers or pins strike against a ribbon and paper to print the test. It produces loud sound during printing, so they are called noisy printer. Example Dot Matrix Printer, Daisy Wheel printer, Drum printer.

Dot-matrix printer (डटम्याट्रिक प्रिन्टर)- Dot-matrix printer are character printers that print one character at a time. It can print all character and all kinds of images as a pattern of dots. A dot-matrix printer has a print head that moves horizontally (left to right and right to left) across the paper. To print a character, the printer activates the appropriate sets of pins as the print head moves horizontally. डटम्याट्रिक प्रिन्टरले कागजमाथि रहेको मसी दलेको रिबनमा हेड पिनहरले हिर्काएर अक्षर, अंक वा चित्रहरु छाप्ने गर्छ । यो प्रिन्टर सस्तो छ तर पाइ स्तरीय हुँदैन ।

Drum printer: - Drum printer are line printers that print an entire line at a time. It consists of a solid cylindrical drum with characters embossed on its surface in the form of circular bands. Each bands consists of all printing characters supported by the printer in its characters set. The drum printer has a set of hammers mount in front of the drum in a manner that an inked ribbon and paper can be placed between the hammers and drum. A character is printer at a desired position by activating the appropriate hammer when the character embossed on the band at the print position passed below it.

Non-impact printer- They use thermal, chemical, electrostatic laser beam or inkjet technology for printing the text. Non-impact printers are faster than impact printers, they do not produce sound while printing. Example ink jet printer and laser printer.

Inkjet printer (इन्कजेट प्रिन्टरे): - Inkjet printer is character printer that form character and all kinds of images by spraying small drops of ink on a paper. The print head of an inkjet printer contains up to 64 tiny nozzles that can be heated up selectively in a few microseconds by an integrated circuit resistor. Inkjet printer produces higher quality printing than dot-matrix printer. इन्कजेट प्रिन्टरले स-साना मसीका थोपाहरु कागजमा छर्केर अक्षेरहरु छाप्ने गर्दछ । यसको छपाइ निकै स्तरिय हुन्छ ।

Laser printer (लेजर प्रिन्टरे) : - Laser printer is page printer that print one page at a time. Main component of laser printer is laser beam source, mirror, a photoconductive drum and a toner. To print a page of output, the laser beam is focused on the electro statically charged drum by spinning the surface of the drum in a manner to create the pattern of characters and images to be printed on the page. Laser printer produce very high quality output because they form characters by very tiny ink particle. A laser printer can print 4 to 12 pages per minutes or more pages. Laser printers are expensive than other type of printers. हेर्दा फोटोकपी मेसिनजस्तो देखिने, अक्षर वा चित्रहरु छाप्नका लागि विम प्रयोग गर्ने प्रिन्टरलाई लेजर प्रिन्टर भनिन्छ ।यसमा प्लाष्टकको मसिनो धुलो मसी(टोनर) को प्रयोग गरिएको हुन्छ । टोनरलाई लेजर विमले प्रयोगद्वारा कागजमा लेखिने काम हुन्छ ।यसले निकै गुणस्तरीय छपाई दिन्छ ।

Difference between impact and non-impact printer

Impact printer	Non-impact printer
1.      It strikes an inked object i.e. ribbon to form letters	1.      It uses electrostatic or thermal technology to form letter.
2.      It produces more sound while printing	2.      It does not produce sound while printing
3.      It is slower in speed	3.      It is faster in speed
4.      It produces low quality output.	4.      It is higher quality output
5.      It is cheaper in cost	5.      It is more expensive in cost
6.      It normally uses continuous paper sheet	6.      It normally uses individual paper sheet
7.      It uses inked ribbon for printing	7.      It uses toner or cartridge for printing.
8.      Impact printers use old printing technologies	8.      Non–impact printers use latest printing technologies
9.      E.g. Dot matrix printer, daisy wheel printer	9.      E.g. laser printer, inkjet printers

Memory devices: - A memory is a device or medium that can accept data, hold them and deliver them on demand at a later time. It is the capacity of computer to store data and information, Memory are of two types. they are primary memory and secondary memory.

कुनै पनि डाटा, इन्फरमेसन, रिजल्ट , प्रोग्राम आदिलाई भविष्यमा गर्नका लागि अस्थायी वा स्थायी रुपमा भण्डारण भइका कम्प्युटर अङ्ग वा भागहरुलाई मेमोरी भनिन्छ । कम्प्युटरको सिस्टम युनिटभित्र र्‍याम र रोम  मेमोरीको रुपमा रहेका हुन्छन । सिस्टम बाहुर हार्डडिस्क, CD, DVD, pen ड्राईभ आदि ।

1)      Primary Memory: It is also called main memory or internal memory. This memory consists of some integrated circuit(IC) chips either on the motherboard or on a small circuit board attached to the motherboard of a computer system. This memory allows CPU to store and retrieve data very quickly. The primary memory included RAM and ROM.

a)          RAM (Random Access Memory) (र्‍याम) - RAM is a volatile memory and losses all its data when the power is switch off or restart the computer. It is the main memory of the computer system that stores the data temporary and allows the data to be accesses in any order. RAM stores the application program and data on which the user is currently working so that the processor can easily access the required application program and data in a less amount of time. It is also known as read/write unit memory because it can perform both read and well as write operation. The speed of RAM is faster than other device such as hard disk, floppy disk etc.कम्प्युटरमा तत्काल प्रयोग गरिरहेका डाटा र निर्देशनहरुलाई राख्न प्रयोग गरिएको मेमोरीलाई र्‍याम भनिन्छ । कम्प्युटरमा गरिने जुनसुकै कार्यहरु पनि र्‍याममा नै गरिन्छ । र्‍याममा भण्डारण गरिएका सम्पूर्ण डाटाहरु र प्रोग्रामहरु सबै अस्थायी हुन्छन र कम्प्युटर अफ गर्ना साथ सबै मेटिएर जान्छन् । र्‍याममा हामीले डाटाहरु पढ्न र लेख्न दुबै काम गर्न सक्छौं । र्‍याम को मेमोरीलाई किलोवाइट र मेगावाइटमा गरिन्छ । यसको स्पिडलाई मेगाहर्जमा नापिन्छ । र्‍याम हरु बिभिनन्न क्षमातामा उपलब्ध छन् । जस्तै 1GB, 2GB आदि ।

Read Only Memory (ROM)(रोम):-ROM is a computer memory on which data are pre-recorded. The programming code and /or data on a ROM chip is written to the chip at the factory. It can be read, but it cannot be erased or removed so it is called non-volatile memory. It's permanent. ROM retains it data or content even when the computer is turned off.कम्पयुटरको स्थायी मेमोरी हो । यसमा भण्डारण गरिएका डाटाहरु स्थायी हुन्छन् अथवा कम्प्युटर स्वीच अफ गर्दा मेटिदैनन् । यसका डाटाहरु कम्प्युटर निर्माण गर्दा कम्पनीमै भण्डारण गरिन्छ । रोम डाटाहरु लेख्न सकिदैन वा पढ्न मात्र सकिन्छ । कम्प्युटर अन गर्न साथ रोममा लेखिएका कुराहरु स्क्रिनमा देखा पर्न थालिहाल्छन् ।

Difference between ROM and RAM

ROM	RAM
It is nonvolatile permanent memory	It is volatile temporary memory
It is not changeable	It is easily changeable
It is mainly used to write system programs	It is mainly used  to hold data for processing.
It is useful for experts related computer organization	It is useful for general user for programmers
The price of ROM are comparatively low.	The price of RAM are comparatively high.
The instruction is written into the RAM at manufacturing time	The instruction is written into the RAM at the time of execution.
Physical size of ROM chips smaller than RAM chip	Physical size of RAM chips bigger than ROM chip
The accessing speed in ROM is slower, Rom cannot boost up the processor speed.	The accessing speed in Ram is faster, it assist the processor to boost up the speed.
Its type PROM, EPROM, EEPROM	Its types are SRAM, DRAM

Cache memory: It stores recently used data and instruction in a pace where it can be accesses extremely very fast. It is kept in between the CPU and the main memory which acts as an intermediate between CPU and the main memory. when some data or instruction are required by the CPU it first looks into the cache memory. It is must faster than RAM or the main memory, but much expensive too.

यो Memory ले CPU र RAM को बीचमा डाटा transfer गर्ने काम गर्दछ ।

2)      Secondary storage device: - Secondary memory are non-volatile and have lower cost per bit stored but they generally have an operating speed far slower than that of primary memory. It is used to store large volume of data on permanent basic that can be partially transferred to primary storage, whenever required for processing. Example magnetic disk, magnetic tape, optical disk. Secondary storages device is Sequential Access device, Direct Access device, magnetic Disk, Optical Disk, CD-ROM. DVD, hard disk, floppy disk.

Primary memory	Secondary Memory
It is main memory of computer	It is auxiliary or additional memory of computer.
It is directly accessed by CPU.	It is accessed by CPU via an interface i.e. Tape
It is comparatively expensive.	It is comparatively cheaper.
It is used for present purpose.	It is used for future purpose.
Example:- ROM, RAM	Example: Hard disk , floppy disk

The storage devices are divided into following categories:

a)      Sequential Storage devices

b)      magnetic storage devices

c)      Optical storage devices

a)      Sequential Storage device: -  A sequential access storage device is the one which information can be retrieved in the same sequence only in which is is stored. For example, if any 10 items are stored in a sequential access storage device, to access the eighth item you must first access the first seventh items coming before the eight item.

b)      Magnetic Tapes: - Magnetic tapes are mass storage or secondary storage devices capable of storing and retaining large volume of data. Data is stores in the form of zeros and ones. Data stored on a magnetic tape is sequentially accessed which means the content of a magnetic tape are read from the beginning till an appropriate entry is reached.

Advantages

·        Magnetic tapes are cheaper than sequential access devices.

·        Data stored on them can be erased and they can be reused multiple times.

·        magnetic tapes have high storage capacity can can backup sustainable amount of information.

Disadvantages of magnetic tape

a)      Magnetic tapes tend to decorates over time.

b)      Data access is slow and tape drive has to read the entire content of a magnetic tape before finding and accessing data.

Magnetic storage devices: - The surface of these devices are coated with magnetic material such as iron oxide or ferrous oxide, which can be magnetized that is which reacts to a magnetic field, the surface of hard disk are coated with millions of tiny iron particles so that data can be stored on them. Each of these particles can act as a magnet. The write/read head of disk drives or tape drives contain electromagnets that generate magnetic fields in the iron on the storage medium as the head passes over the disk or tape.  The presence of a magnetic files represents a 1 and its absence represent a o bit. Commonly used magnetic storage devices are: -

Zip disk: -The Zip drive is a medium-to-high-capacity (at the time of its release) removable floppy disk storage system that was introduced by Iomega in late 1994. Originally, Zip disks launched with capacities of 100 MB, but later versions increased this to first 250 MB and then 750 MB.

Super disk: -  It is capable of storing about 120 MB of data. Floptical technology combined traditional magnetic tape storage with laser heads. The smaller head size of a laser meant that more data could be written on a given area of tape. Super –Disk Drive could also read and write on older traditional 3.5 –inch floppy disks.

Flash memory: - Flash memory is an advances type of memory which is available as USB memory stick. It is user friendly, portable and cheaper. Example pen drive.

Pen drive (पेन ड्राइभ): - Pen drive is the most popular used magnetic storage device. It is also called flash drive, USB (Universal Serial BUS) drive or thumb drive. It is small in size and can be carried in a pocket like a pen so it names as pen drive.  It is a convenient way of transferring data from one computer to another. It can be considering as a small external hard disk. Its storage capacity range from 128 MB to a few Gigabytes.हेर्दा पेन जस्तै देखिने र निकै सानो साइजका डाटा भण्डारण गर्ने अत्याधुनिक साधान पेन ड्राइभ हुन्  । पेन ड्राइभहरु हेर्दा आकर्षक, हलुका सानो साइज र बढी क्षमता भएका हुन्छन् ।

Memory cards: - Memory card is a small and perfect removal able storage media. We can store and transfer data, music, movie ad picture file wherever we go. SD memory cards are usually intended for cameras and mobile devices. The main drawback is that not all compute has memory card reader, which means we may have to purchase an adapter (card reader) in order to be able to use one.

Optical storage devices: Optical storage is the storage of data on an optically readable medium. Data is recorded by making marks in a pattern that can be read back with the aid of light, usually a beam of laser light precisely focused on a spinning optical disc. An optical disc drive is a device in a computer that can read CD-ROMs or other optical discs, such as DVDs and Blu-ray discs. Commonly used optical storage devices are

1)      CD-ROM :-  CD-ROM stands for Compact  Disc Read only Memory. CD-ROM is a type of optical disc that uses laser technology to store and to read data to and from the disc. Once the information is stored on the CD-ROM, it becomes permanent and cannot be changed(altered). Therefore, it is also called Compact Disc Read Only Memory. The CD-ROM is removable and can be used to transfer data from one computer to another. A typical CD-ROM has storage capacity of 700MB.

Advantages:

1.      It is portable

2.      able to store large amount of text, image and audio video

3.      It is quite cheaper in terms of cost per character stored.

4.      It has a long life span than a magnetic media

5.      It is comparatively reliable and easy to use

Disadvantage

1.      It takes more time to store and retrieve data as compared to hard disk

2.      It requires special drives to read/write

3.      We can only read the data written in it but cannot edit the data

4.      Once recorded, it cannot be erased and dilled with new data

2)      DVD ROM: - DVD stands for Digital Video DISC or Digital Versatile DISC. It is an extremely high capacity optical disc with storage capacity from 4.7 GB to 17 GB. DVD disc is specially used to store movie, films. It is also used to store huge database, music, large software etc.

3)      Blue Ray: - A blue laser is used to record more data onto a disc which is the same physical size as a DVD. It can store large amount of data compared to DVD, up to 50 GB for dual layered disc.

Computer assembled

·        Power supply (220 volt)

·        Motherboard(मदर बोर्ड): - It is the main circuit board of a microcomputer. A motherboard connects almost all other parts together in a computer. Motherboard contain CPU, BIOS, mass Storage interface, serial and parallel ports expansion slots and all the controller required to control standard peripheral devices such as display screen, keyboard and disk drive, as these chips that reside on the motherboard are known as motherboard's chipset. कम्प्युटर सिस्टमको मुख्य सर्किट बोर्डलाई मदरबोर्ड भनिन्छ । मदरबोर्ड सर्किट बोर्ड सिपियु र्‍याम लगायतका धेरै भागहरुमा टाँसियर रहेका हुन्छन् ।

Parts of Mother board

Processor:-

RAM Chips

Display card

MODEM card

Controller card

·        TV card:- A TV tuner card is a kind of television tuner that allows television signals to be received by a computer. Most TV tuners also function as video capture cards, allowing them to record television programs onto a hard disk much like the digital video recorder (DVR) does. The interfaces for TV tuner cards are most commonly either PCI bus expansion card or the newer PCI Express (PCIe) bus for many modern cards, ExpressCard, or USB devices also exist. The card contains a tuner and an analog-to-digital converter (collectively known as the analog front end) along with demodulation and interface logic.

TV काडको माध्यबाट Televison हेर्न सकिन्छ । यसलाई पनि mother board मा राखिएको हुन्छ । यसको port मा TV केबल जडान गरेर आवश्यकतानुसार TV channel हेर्न सकिन्छ ।

·        Sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces used for professional audio applications. Sound functionality can also be integrated onto the motherboard. The integrated sound system is often still referred to as a sound card. कम्प्युटरको Motehrboard मा attached गरिएको हुन्छ । यसबाट sound भित्र लैजान वा बाहिर ल्याउनका लागि व्यवस्था गरिएको हुन्छ । CPU को पछाडि sound का लागि port राखिइको हुन्छ ।

·        Printer card (port)

·        Hard disk

·        Floppy disk

·        CD Drive controller etc.

·        Power connector

Processor (Central processing unit(CPU) सेन्ट्रल प्रोसेसिङ यनिट:- The ALU and the CU of the computer system are jointly known as  the central processing unit. It is just like brain that takes all major decision, makes all sort of calculation and directs different parts of the computer functions by activating and controlling the operations.सेन्ट्रलो प्रोसेसेङ युनिटलाई कम्प्युटरको मुटु भनिन्छ, जुन यसको अती संवेदनशील भाग हो । सि.पि.य. भनेको मदरबोर्डमा टाँसियर रहेको एक सानो माइक्रोप्रोसेसर चिप्स हो । कम्प्युटरले काम गर्दा सम्पूर्ण डाटा प्रसोधन यसै यनिटभित्र गर्दछ । सिपियु भित्र मुख्य तीन युनिटहरु हुन्छन् । ती युनिटहरु कन्ट्रोल युनिट, अर्थमेटिक/लजिकल युनिट र मेमोरी युनिट हुन् । यसका अतिरिक्त इथरनेट कार्ड, साउन्ड कार्ड, सीडि ड्राइभ, डिक्स ड्राइभ आदि पर्दछन्  ।

·        Cooler Fan: CPU is mounted on the motherboard, hidden under the cooling fan and heat sink.

·        Ram- Random Access memory

·        Memory bank

·        Data Cable

·        Hard Disk

Computer Hardware: The physical part of the computer which we can see, touch and feel. The hardware consists of electronic circuits and all the devices used to perform various function in the computer system. Example: keyboard, mouse printer, scanner, speaker web camera, Motherboard etc. कम्प्युटरमा आँखाले देखिने वा हेरेर,छोएर अनुभर्ति गर्न सकिने parts सम्पूर्ण लाई नै Hardware भनिन्छ ।

The computer hardware devices fall into following categories: -

Motherboard:

CPU(Central Processing Unit):- The CPU is the main IC chip on computer's motherboard. CPU is also known as electronic brain of computer which controls and directs all the activities of the computer system. CPU consists of the following components

ALU

CU:-

Registers

ALU(Arithmetic and Logic Unit)अर्थमेटिक लजिकल युनिट: ALU performs fundamental mathematical operation consisting of addition, subtraction, multiplication and division. It also performs logical operation includes AND, OR, NOT and comparison includes equal, less than, greater than etc. कम्प्युटरको सि.पि.यु. भित्र रहेको अर्थमेटिकल युनिटले अंकगणितीय हिसाबहरुले जस्तैः जोड, घटाउ, गुणन वा भाग गर्दछ भने लजिकल युनिटले कुनै दुई अंकहरुलाई एक आपसमा तुलना गरी बराबर, ठुलो वा सानो के छ पत्ता गराई आवश्यक नतिजा दिने काम गर्छ ।

Control unit(CU)(नियान्त्रण एकाइ): - It coordinates and control the operation of a computer system. It controls the activities between memory and ALU and between CPU and I/O device. So it is also referred called central nervous system of the computer. नियन्त्रण एकाईले कम्प्युटर प्रणालीभित्रका सम्पूर्ण भागहरुलाई नियन्त्रण गर्नुको साथे प्रोग्रामका निर्देशनहरु पालना गरी काम गर्न लगाउँछ । यस एकाइले कम्प्युटरलाई प्राप्त भएका निर्देशनहरु बुझी प्राप्त डाटाहरुलाई प्रसोधनका लागि कहाँ पठाउने हो, प्राप्त रिजल्ट कहाँ भण्डारण गर्ने र कहाँ पठाउने सम्पूर्ण निर्णय गरी एक आपसमा विद्युतीय संकेतहरु आदानप्रदान गराई काम गराउँछ । 

Registers: - A register is a temporary storage device which holds the data and instruction as long as it is being interpreter and executed. When the data and instruction are fetched from the main memory for processing such data and instruction have to be stored in one of the registers of the CPU. The register can contain the address of memory location where data is stored rather than the actual data itself.

                                                            Fig: CPU components               

The bus (System bus): - A set of electronic signal pathway allows information and signals to travel between components inside or outside of a computer. Buses are the electronic pathways through which data travel in computer system. Example: a bus connects the disk controller, memory and input/output ports to the microprocessor.

 There are mainly three types of internal bus

1.      Data bus:-It is the line or path for as actual data flow to be sent to the components. It carries data from the microprocessor to memory during the write operation and memory to microprocessor during the read operation, newest bused can handle 64 bits which is 64 wires or line of communication, the data bus moving into or inside the CPU runs faster than outside the CPU.

2.      Address Bus: -The address bus is a set of wires that allows bits of information with memory addresses for the CPU.

3.      Control bus: - This type of bus caries necessary timing and control signal to manager and coordinates the activities of entire computer system. The control bus is used to transmit different types of signal such as read, write, acknowledge and interrupt etc.

Figure:- System bus

Expansion slots: -the expansion slots are made up of the electronic pathways that connect the different external device (monitor, telephone line, and printer) to the rest of the computer.

Cooling Fan: -

CMOS battery: - Motherboard battery is also called CMOS Battery which is used to maintain the clock function and any setting saved in CMOS storage.

ROM BIOS (ROM Basic Input Output System):-The ROM BIOS chip contains a small collection of programs (software) which are permanently stored on the motherboard ad used. Example when the PC starts up.

Microprocessor: -  A microprocessor contains all the circuits needed to perform arithmetic, logic and control function. The core activities of a computer on a single chip are possible due to the development of microprocessor. Hence it became possible to build a complete computer with a microprocessor. A microprocessor has limited number of instruction that is understands is called is its instruction set. Each instruction involves a series of logical operation that are performed to complete each task. The major microprocessor manufactures are Intel, Motorola, IBM, Advanced Micro device (AMD), and Cyrix. The following are the major microprocessor design technologies.

       I.          CISC Technology: - CISC Technology (Complex Instruction Set Computing) combines the different instructions into one single CPU and each instruction has the ability to perform several task based on mini programs or microcode integrated into the processor.

     II.          RISC Technology: - Reduced instruction set computing or RISC is a CPU design strategy based on the insight that a simplified instruction set provides higher performance when combined with a microprocessor architecture capable of executing those instructions using fewer microprocessor cycles per instruction. A computer based on this strategy is a reduced instruction set computer, also called RISC. The opposing architecture is called complex instruction set computing (CISC).

   III.          EPIC technology: - The Explicitly parallel instruction computing technology are simple and more powerful the RISC and CISE processor design technology. This technology breaks through the sequential nature of conventional processor design technology which allows the software to communicator explicitly to the processor when operation can be done parallel. It is mainly used in fifth generation 64-bit, high end server and work station.

UPS(Uninterruptible Power Supply):- An uninterruptible power supply (UPS) is a device that allows a computer to keep running for at least a short time when the primary power source is lost. It also provides protection from power surges.

A UPS contains a battery that "kicks in" when the device senses a loss of power from the primary source. If you are using the computer when the UPS notifies you of the power loss, you have time to save any data you are working on and exit gracefully before the secondary power source (the battery) runs out. When all power runs out, any data in your computer's random access memory (RAM) is erased. When power surges occur, a UPS intercepts the surge so that it doesn't damage the computer.

बत्ती बिजुली अभावमा कार्यसम्पासन गर्नका लागि UPS को प्रयोग गरिएको हुन्छ । यसले कम्प्युटरको डाटा लाईभ मा रहन र कार्यसम्पादनलाई प्रभावकारी बनाउन मद्दत गर्दछ । यसले घन्टौसम्म विद्यत आपूर्ति supply को कार्य गर्दछ । आजकल Battery supply तथा powerful UPS को प्रयोग गर्ने गरिन्छ ।

Computer software: - A program is a collection of set of instruction that perform specific task to solve a particular problem is called program. A group of programs that a computer uses to perform specific task is called software. Example Photoshop, dia etc.

Difference between program and software

Program	Software
1.      It is a collection of set of instruction	1.      It is a collection of programs
2.      Programs is generally created by individual user or groups of users	2.      Software is developed to the various programs
3.      A program itself is an independent	3.      Software is dependent to the various programs
4.      Program is limited and specific	4.      Software is unlimited an covers wide area
5.      It cannot be categorized according to needs and use.	5.      It can be categorized as system, application.
6.      Normally program does not license to use	6.      Generally license is required for using commercial software.
7.      Demand less memory during execution	7.      Demands more resource during execution
8.      C program to calculate area	8.      e.g. MS-word, Mozilla Firefox, paint etc.

Type's of software: - Software can be divided into two major categories

Application software

System software

Utility Software

System software (सिस्टम सफ्टवेयर): -It is responsible for accessing computer hardware and providing resource to application software. Task such as controlling operation, moving data, executing the application programs etc.

सिस्टम सफ्टवेयर(system software):- सम्पूर्ण कम्पयुटर सिस्टमको सञ्चालन तथा नियन्त्रण गर्ने प्रोग्रामहरुको समूहलाई सिस्टमसफ्टवेयर भनिन्छ । सिस्टम सफ्टवेयरले कम्प्युटर र एप्लिकेसन सफ्टवेयरको बीचमा बसेर दोभासेको रुपमा काम गर्दछ । यो सफ्टवेयर विना कम्प्युटर सञ्चालन गर्न सकिदैन । यस सफ्टवेयरलाई निम्न ३ प्रकारमा विभाजन गर्न सकिन्छ ।

Basically, system software supports the following

a)      Running of other programs

b)      Supports development of other application software

c)      Communicating with peripheral device such such as printer, card reader etc.

d)      Developing of other types of software

e)      Maintaining the use of various hardware resources such as memory, peripherals, CPU etc.

Types of system software

1.      Operation system software (अपरपेटिङ सिस्टम सफ्टवेयर): - An operating system is the collecting of program that acts as an interface between the user and the computer and hardware of the computer providing and operational environment to the users and application programs. Example Windows 95/98/2000/NT/XP/Vista/7/8/8.1/10, UNIX, Linux, Novell Netware, MS-DOS etc. कम्प्युटर व्यवस्थापनको काम गरी कम्प्युटर सचालन गराउने सफ्टवेयरलाई अपरेटिङ सिस्टम सफ्टवेयर भनिन्छ । यसले प्रयोगकर्ता, हाईवेयर र प्रोग्रामहरुको बीचमा समन्वय काय, गराउंछ । MS DOS, MS Windows, Linux, Unix इत्यादि अपरेटिङ  सिस्टमका उदाहरण हुन् ।अपरपेटिङ सिस्टम सिङ्गल युजर र मल्टियुजर सिस्टम गरी दुई प्रकारका छन् ।

Function of an operating System

       I.          Input/output Management: This function keeps track of I/O devices i.e. which job is in use and by which job that device is using. It allocates job and de-allocates the devices after the completion of the job. Input and output management operating system is responsible for

·        It activates general device driver software. Device driver software is used or utilization of input /output device.

·        To run driver software for specific hardware when required.

     II.          Command Interpretation: - This function of operating system takes care of interpreting user commands and directs the system resource to handle the request.

   III.          Memory Management: Memory management function of an operating system takes care of allocation and de-allocation of memory space to the program need of these resources.

Memory management operating system is responsible for

·        Keep track which memory segment is using by whom allocate and deallocate various memory spaces as needed.

·        Manages for blank memory space available

·        Decides the location for storage of new program.

   IV.          Security Management: -This function protects the resources and information of computer system against destruction and unauthorized access.

Security Management of operating system is responsible for

·        Protection and security of files and folders

·        Preventing theft, corruption and loss of data.

·        Hiding the system files and folders from unwanted modification.

     V.          File Management: This function take cares of file related activities such as organization, storage, retrieval, naming, sharing and protection of files.

File management is responsible for

·        Create and deletion of files

·        Access to files for reading and writing

·        Protect files against system failure.

·        Saving of files among various users.

·        Mapping files into disk storage.

·        Support for manipulation of file and folders.

   VI.          Deadlock prevention: - Deadlock is the situation which can arise when a resource is shared by two or more process. In such situation the operating system carefully handles and allows the resource properly to avoid the problems.

 VII.          Interrupt handling: -  there are two types of interrupt: -

Hardware:-or external interrupt: - they are initiated through the computers interrupt pins by external devices.

Software or internal interrupt: - internal interrupt arise from illegal or erroneous ise of an instruction or data. Internal interrupt are called traps. Interrupts due to iernal error condtions are registered overflow attempt to divided bu zero, stack overflow etc

VIII.          Virtual Memory management: This function operates by in which the free space of secondary memory such as hard disk is used as primary or main memory when we are running large program than capacity of main memory especially in multiprogramming system.

Security Management of operating system is responsible for

·        Protection and security of files and folders

·        Preventing theft, corruption and loss of data.

·        Hiding the system files and folders from unwanted modification

       Input/output management: This function keeps track of I/O devices i.e. which job is in use and by which job that device is using. It allocates job and de-allocates the devices after the completion of the job. Input and output management operating system is responsible for

IX. Process management: This function takes care of creation and detection of processes, scheduling of system resources to different processes required them and providing mechanism for communicating between the processes.

Process management is responsible for

·        Creation and deletion of processes

·        Providing a mechanism for communication among them

·        Scheduling of various system resources to the different process request them.

2.      Language processor /transiting programs(ल्याङ्वेज प्रोसेसर सफ्टवेयर): - The program or software which translates the instruction written in human convenient form to machine language code is called Language Processor or Translating Program, Example of language Processors are Compiler, Assembler and Interpreter.

प्रोग्रामरले लेखेका कुराहरुलाई कम्प्युटरको भाषामा परिवर्तन गरी सञ्चालन गर्न लायक बनाउने सफ्टवेयर ल्याङ्वेज प्रोसेसर सफ्टवेयर भनिन्छ । यसले हाइ-लेबल वा लो लेबल भाटामा लेखिएका कम्प्युटरका प्रोग्रामहरुलाई मेसिन कोडमा ट्रान्सलेट गरिदिने काम गर्दछ । यी सफ्टवेयर निम्न तीन प्रकारका हुन्छन (एलेम्बलर, कम्पाइलर, इन्टरप्रेटर)

Utility software (युटिलिटी सफ्टवेयर): - Software that supports operation and management of a computer system by providing a variety of support service is called system utilities or utility software. This software performs services such as editing text or program, debugging, program, sorting records, merging files, transferring data, printing a file etc.

यो सफ्टवेयरले प्रयोगकर्ताका लागि विभिन्न औजारहरुको व्यवस्था मिलाउने काम गर्दछ, जसबाट काम गर्न सरल हुन्छ । युटिलिटी सफ्टवेयरले फाइल तथा डाइरेक्टीहरुलाई क्रम मिलाएर राख्ने, विभिन्न फाइलहरुको ब्याकअप तयार पार्ने, डिस्कलाई फर्म्र्याटिङ गर्ने, डिलिट गरेका डाटाहरुलाई फेरि प्रोग्राममा ल्याउने सक्ने बनाउने, बिग्रेका डाटाहरुलाई सच्याउने, भाइरस हटाउने, कम्प्युटरका पार्टपुर्जा निरीक्षण गर्ने लगायतका विभिन्न कार्यहरु गर्दछन्।

Frequently used software's are

Disk defragmenter: - It is the system tool which allows to defragment (make together) the fragmented (scattered) data, files and restore into the whole file or fill document which increase the system performance and access speed of data.

Disk cleans up: -This system tool helps to keep window operating system smooth as it should be. It inspects the hard disk of PC and looks for unnecessary files that can be safely deleted allowing up the valuable disk space.

Scandisk: - This system tool allows the disk up to data for data storage and retrieval system. It scans, detect and repair the errors in the disk. The scan disk checks specified disk for bad sectors and other related problem and make possible repairing.

Backup: - This tool allows to make reserve or extra copy of data, file, program etc. which can be restored later in its original location when they are deleted or not available.

Application software (एप्लिकेसन सफ्टवेयर) :-  Application software's are the sets of one or more programs designed to carry out the operation for a specified application directly to the users. प्रयोगकर्ताहरुको आफ्नै आवश्यकता र इच्छाअनुसार काम गराउनका लागि बबाइएका प्रोग्रामहरुको समुहलाई एप्लिकेसन सफ्टवेयर भनिन्छ। एप्लिकेसन सफ्टवेयरले प्रयोगकार्ता र सिस्टम सफ्टवेयर  बीचमा इन्टरपफेसका रुपमा काम गरिदिएर पर्योगकर्तालाई निश्चित काम गर्ने अनुमति दिन्छन् । यस्ता सफ्टवेयरहरु यस्ता सफ्टवेयरहरु चिठीपत्र, पुस्तकका काइहरु सिजाइन गर्न, हिसाब गर्न, तथ्याङ्कसम्बन्धी समस्या हल गर्न, टिकट रिजर्भेसनलगायतका कामहरु गर्न प्रयोग गरिन्छ । एप्लिकेसन सफ्टवेयरलाई निम्न दुई समूहमा विभाजन गरिइका छन्

Used for

Word processing

Spreadsheet

Graphics

Designing

Multimedia etc.

Tailored software(टेलर्ड सफ्टवेयर): - It is the software specially designed to meet the specific requirement of an organization or individual. Example result processing of NEB, printing of certificates, payroll software, sales, ledger etc. Tailored software's are written in high level language such as BASIC, PASCAL, FORTRAN C, C++ etc. कुनै पनि संघसंस्था वा व्यक्तिको निश्चित आवश्यकता पूरा गर्न बनाइएका निश्चित प्रकारका सफ्टवेयरलाई टेलर्ड सफ्टवेयर भनिन्छ । जस्तैः कुनै बसको टिकट काट्दा, कुनै कम्पनी वा पसलमा बील काट्न प्रयोग हुने सफ्टवेयरहरु टेलर्ड सफ्टवेयरहरु हुन् ।

Packaged software (प्याकेज सफ्टवेयर): - Packaged software is a generalized set of programs that allows the computer to perform the specific data processing job for the users. Example Word processing software, Spreadsheet Software, database software etc. कम्प्युटर प्रयोगकर्तालाई दैनिक जीवनमा गर्नपर्ने विभिन्न कामहरु गर्न सजिलो पार्ने उद्देश्यले बनाइएका व्यवस्थित प्रोग्रामहरु समूहलाई प्याकेज सफ्टवेयर भनिन्छ । केही प्याकेज सफ्टवेयरहरु निम्न छन् ।

Word processing (वर्ड प्रोसेसिङ): - A word processor is a software that allows to create, edit, view, format and print text document in the computer. Example Microsoft Word, Word Perfect, Word Star, Word Pad, Vim Editor, MS Works, AppleWorks etc. यस अन्तर्गत Microsoft Word, Word Perfect, Word Star, Word Pad, Vim Editor जस्ता प्रोग्रामहरु पर्दछन् ।यी सफ्टवेयर प्याकेजहरु कुनै पनि प्रकारका शब्दगत कार्यहरु गर्न सकिन्छ ।

Features of word processor

·        Fast operation: typing text in a Word Processor becomes very fast as there is no mechanical carriage movement associated.

·        Editing text features: Any type of operation like insert, delete, modify the documents and undo/redo, find/replace can be perform very easily. These insertion, deletion or correction can be performed at any time in place of the text. These alternations can be made before and after typing the entire document. Similarly, move or copy a section or block of text object from any location of the same document or other document to another location in the entire material of the document too.

·        Formatting features: The electronic typed text can be appearing or insert in any form or style like bold, italic, underline, different fonts, font size, its color and paragraph formatting can be made.

·        Permanent storage: - By the help of Word Processor, files and documents can be saved as long as preferred and saved files and documents can be retrieved whenever desired.

·        Graphics: It provides facilities to insert text, objects (picture, graph etc.) anywhere in the document whenever necessary.

·        OLE (Object linking and embedding): Modern Word Processors provide facilities to link or embed objects in a document. OLE is a program–integration technology that can use to share information between programs through objects. Objects are saved entities of different types like charts, equations, pictures and audio/videos clips.

·        Review the document: -  Word Processor not only is capable of checking spelling mistakes but also can suggest possible alternatives for incorrectly spelt word i.e. it provides to facility of using speller and thesaurus (synonyms and antonyms words).

·        Mail merge: It is an option used to merge a list of information such as names, address, e-mail, phone number (data source) with the main document. The main document contains original text (merge fields) with data area at appropriate places to produce a number of copies of merged document while defined the merging task. The main document is created using the Mail Merge Helper dialogue box.

·        Searching: It facilities to search for any word or text and replace or delete with other necessary ones in the entire material of the documents very easy.

·        Print design: It provides print preview, printing area (four sides), no. of copies, paper size, before print to view the document exactly as per the convenience or not.

Popular word Processing Packages

Ms-Word	Ms Write	Amipro	Word Star	Kingsoft Writer	Lotus notes
Louts Word Pro	Word Perfect	Apache Open Office Writer	Ted	MultiMate	Professional Write

Uses of Word Processor

·        To create resumes/bio data        Update a blog

·        Articles Cover letters                        World wide web pages

·        Directories                                         Advertisements

·        Newsletters                                        Brochures

·        Report writings                                 Annual reports

·        Books

·        Mail Merge: - we may use mail through the old post office or using the recent email technology. If we have to send the same mail content to multiple recipients by addressing each recipients, then we have to make multiple mail documents repeatedly. To solve this problem, word processors provides feature called mail merge. This feature merges the letter with the database of names and addresses to produce document for the multiple mail recipients. The mail merge features produces personalized multiple copied of letters, pre-addressed envelopes or mailing labels for mass mailing by combining a words document which contains the fixed text with the variables that are placed in each letter from a data source. The data source can be spreadsheet or a database which has fields or column matching each variable in the template, For the mailing purpose, the data source should have the name or address of individual to whom the mails are to be sent. However, using mail merge, we can prepare multiple document with other types of variables as well.

When the mail merge feature is executed, the word processor generates multiple copies of the text document for each row in the database by substituting the variables in the template with the value in matching column. Most of the word processing packages available today are capable of performing mail merge.

Or ,

Mail merge consists in combining mail and letters and pre-addressed envelopes or mailing labels for mass mailings from a form letter. Microsoft Word can insert content from a database, spreadsheet, or table into Word documents. This feature is usually employed in a word processing document which contains fixed text (which is the same in each output document) and variables (which act as placeholders that are replaced by text from the data source).

Mail Merge is a powerful tool for writing a personalized letter or E-mail to many people at the same time. It imports data from another source such as Excel and then uses that to replace placeholders throughout our message with the relevant information for each individual we are messaging. mail merge भन्नाले चिठीपत्र जनाउँछ mail भन्नाले चिठीपत्र र merge भन्नाले कुनै पनि दुई वा दुइभन्दा बढी पक्ष वा विष्यवस्तुहरुलाई जिड्ने कामलाई जनाउँछ । mail merge भन्नाले एउटै बेहोरा चिठी बिभिन्न नाम र ठेगनामा पठाउनु परयो भने प्रयोग गरिने word को toolलाई जनाउँछ ।

Uses of mail merge

When you need to mail copies of the same letter to multiple recipients, create custom envelopes or labels to mail to various contacts or you want to make a mass email sound more personal, you can use the Mail Merge feature in Microsoft Word. With this tool, you can use data from an existing Excel worksheet, a list in Word or your Outlook contacts and customize a document quickly.

Spreadsheet: - The data or point of information are arranging in tabular form (i.e. rows and columns) which is called spreadsheet.  An electronic spread sheet is software that accepts data in a tabular form (i.e. in rows and columns) and allows you to calculate and manipulate them according to your requirement. Example VisiCalc, Lotus 1-2-3, Microsoft Excel, Quattro Pro, MS Works etc.Spreadsheet have a wide range of uses from family business to corporate earnings statements .1,048,576 rows and 16,384 (XFD) columns in Excel 2016.

Excel 2007

1,048,576

16,384 XFD

यस अन्तर्गत VisiCalc, Lotus 1-2-3, Microsoft Excel जस्ता प्रोग्रामहरु पर्दछन् । यिनीहरुको प्रयोग विभिन्न अंकसम्बन्धी हिसाबकिताबहरु ताख्नका लागि गरिन्छ ।

Cell: - A cell is the interaction between a row and a column on a spreadsheet that stats with cell A1. A cell is a box in which you can enter a single piece of data. The data is usually numeric value or a formula. The entire spreadsheet is composed of rows and columns of cells. Individually cells are usually identified by a column letter and a row number. Data enter into spreadsheet program is always stored in a cell. Example A2 species the cell in column A and row 2.

Worksheet: - An excel worksheet is a single spreadsheet that contains cells organized by rows and columns. A worksheet begins with row number one and column A. A worksheet is a collection of cells on a single sheet where you actually keep manipulate the data. In excel 2010, the maximum size of a work sheet 1,048,576 rows and 16,384 columns.

Work book: - A work book is an excel file that contain one or more worksheet. Each workbook can contain many worksheets that you use to organized various kind of related information. It contains three worksheets by default.

Features of spreadsheet software:

·        Allows data entry, storage, calculation and presentation.

·        Formatting of data for making it attractive by using tools like font, font color, font size.

·        Simple computing operations like copy, cut, paste, find, replace etc.

·        Sorting data either or ascending or descending order on the basis different fields.

·        Formula for calculations using cell address including mathematical, statistical, trigonometrically etc.

·        Allow to share workbooks, allowing multiple users to edit the same workbook at same time.

·        Provide various chart types and shapes like Pie, Bar, XY, Stack Bar, Area, 3D-Pie etc.

·        Data validation for setting data entry rules.

·        Internet feature including a web toolbar and the ability to create hyperlinks and to save files using save as HTML options.

·        Advanced features like goal seek, scenario, auditing, what-if analysis, pivot table, pivot chart etc.

·        Supports the high level feature of object linking & embedding i.e. data from MS WORD can be safely & easily put put and linked with data in MS EXCEL and vice versa.

·        Support natural language formulas.

Spread sheet software's

MS EXCEL	Simple Spreadsheet	Ability Office Spreadsheet	Lotus1-2-3	Open Office.org Calc
Gnumeric	Google Spreadsheet	TABULUS	WikiCalc

Uses of spreadsheet

·        Arithmetic and statistical calculations.               

·        Preparation of profit and loss account.

·        Financial forecasting.

·        Reports and balance sheet.

·        Preparation of income statement.

·        Charts (PIE, BAR etc.)

·        Regression analysis.

·        Preparation of tax statements.

Database software (डाटावेस): - A database is an organized collection of related data where data can be known facts and figure about person, place, event or things. For e.g. phone diary, result sheet. Database contains only data not information so it should be analyzed to get required information. Example MS Access, Oracle, FileMaker Pro

Etc. यस अन्तर्गत MS Access, Oracle, dBase, Foxproजस्ता प्रोग्रामहरु पर्दछन्। यिनीहरुको प्रयोग डाटाहरुको व्यवस्थानका लागि गरिन्छ ।

Graphics software (इमेज प्रोसेसिङ):-It enables us to use a computer system for creating, editing, viewing, storing, retrieving and printing of designs, drawing, picture, graphs etc. यस अन्तर्गत Paint, Photoshop, Corel draw, image setter जस्ता प्रोग्रामहरु पर्दछन्।यी सफ्टवेयरहरु फोटो र ग्राफिक्ससम्बन्धी प्रशोधन र डिजाइन गर्न प्रयोग गरिन्छ ।

Entertainment software: - It allows a computer to be used as an entertainment tools.  Example video game.

Communication Software: Allows to connected computers to communicate each other using audio, video or chat-based medium. Eg: MS Net Meeting, IRC, ICQ

Presentation Software: Used to create multimedia stacks of cards/screens. Eg: MS PowerPoint, Hyper Studio, Flash, Super Card, HyperCard.  यसको प्रयोगबाट slide show अथवा Animation प्रस्तुत गर्न सकिन्छ । विशेषतः कम्प्युटर ले दिने output विषयक कार्यलाई projector को माध्यमबाट Multimediaको प्रयोग गरी कार्यक्रम प्रस्तुत गरिने पद्धतिलाई PowerPoint भनिन्छ ।

·        यो एक Presentation software हो ।

·        जसको माध्यमबाट Slide design  र Animation गरिन्छ ।

·        छोटो, सरल र संक्षिप्त भाषाबाट कुनै पनि कुरा प्रशिक्षार्थीलाई देखाउन, Animation गर्न यसको प्रयोग गरिन्छ ।

·        तालिम, गोष्ठी, सेमिनार, स्कुल, कलेजहरुमा यसैको माध्यमबाट कक्षा सञ्चालन गर्ने गरिन्छ ।

Example of presentation program are

MS PowerPoint	KPresenter	MagicPoint	Apple Keynote
Simple slides	Openoffice.org Impress	Corel Presentations	Powerdot
IBM Lotus	Opera Show Format	Freelance Graphics	Harvard graphics

Features of Presentation package

·        Allows data entry, storage, calculations and presentations.

·        Formatting of data for making it attractive by using tools like font, fonts color, font size etc.

·        Simple computing operations like copy, cut, paste, find replace etc.

·        Predesigned slide designs can use faster and easier development of presentation.

·        Slide transition, to define how a slide is displayed from the previous one.

·        Predefined slide animation for to developed our own animations.

·        Custom animation to develop our own animations

·        Buttons for the easier navigation from one slide to another.

·        Bookmarks and hyperlink to link different components of a presentation.

·        Provide various char types and shapes like pie, bar, XY, Stack bar, area, 3D- pie etc.

·        Internet features including a web toolbar and the ability to create hyperlinks and to save files using Save as HTML options.

Charactirictics:

·        कम्प्युटर र overhead projector आवश्यक पर्दछ ।

·        Slide तयार गर्न, खोज्न, कपी गर्न , video हेर्ने, Sound भर्न, Slide मा संगीत भर्न समेत सकिन्छ ।

·        फोटोहरुलाई Change गर्न सकिन्छ ।

Internet Browsers:This tools allows one to surf the web, read their emails and also create web pages.

Eg: Netscape Navigator, MS Internet Explorer

Email Programs: This software is mainly used to send and receive emails.Eg: MS Outlook, Netscape Messenger, Eudora, AOL Browser

Desktop Publishing Software: This tool is used to create illustrative worksheets, banners, newsletters, signs, gift cards etc. Eg: MS Word, MS Publisher, Adobe PageMaker

Difference between application software and system software

System Software	Application Software
They are the basic and fundamental computer program, required starting up computer.	They are additional computer programs required after starting the computer to be specific work.
They are independent so they do not need support of application software while working	They are fully dependent to the system software without which they cannot work independently
They communicate with user and hardware device such as mouse, printer, card reader etc.	They communicate with user only to carry out the operation for a specified application
They manage files, folders , documentation etc.	They allow creating and managing only users related specific documents.
They are standard and common for every users	they are general and specific both
System software is written in a low-level language	Application software is written in a high level language like java, C++, .NET, VB etc.
Example operating system, language processors	Example word processing, database,  spreadsheet etc.

Disk Operating system(DOS)/ MS-DOS (Microsoft Disk Operating System): MS-DOSis a command based, single user and single-tasking operating system software developed by Microsoft INC, USA, in 1981. It is a popular operating system for microcomputer. It is design for IBM PC and IBM compatible computer. MS-DOS performs the operation of input output management, memory management, disk checking and formatting, control the flow of data from one part of the computer to other part such as disk to memory and vice-versa. It is responsible for controlling peripheral device such as monitor, keyboard, printer, modems.

Features of MS - DOS

       i.          It is a single user and single-tasking operating system software.

      ii.          It supports both hard disk and floppy disk.

    iii.          It supports various languages.

     iv.          It is a CUI based operating system.

      v.          Hierarchical file directory structure.

     vi.          It uses two types of command: internal and external command.

   vii.          MS-DOS has three essential files for booting the computer: they are IO.SYS (handle input/output process), MSDOS.SYS (manage workspace for application), COMMAND.COM (command interpreter receiver and execute commands)

  viii.          It is 16-bit operating system developed for personal computers.

Windows Operating System:   Microsoft Windows is the popular and widely used graphical user interface(GUI) based operating system developed by Microsoft Corporation USA.Microsoft introduced the first GUI base set of software which is properly known as Windows. Windows OS is very common operating system for personal computer including desktop and laptop. Windows operating system provides WIMP (Windows, Icons, Mouse and Pointer) environment, GUI, desktop, control panel, multitasking. Example: Windows 95 Windows NT, Windows 98, Windows 2000, Windows ME, Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, Windows 8, Windows Server 2012, Windows 8.1, Windows 10, windows server 2016. कम्प्युटर सफ्टवेयरको सञ्चालन एवं नियन्त्रण गर्ने प्रणालीलाई सिस्टक भनिन्छ । अपरेटिङ सिस्टम सफ्टवेयरको अनुपस्थितिमा हामी कम्प्युटरमा कुनै पनि कार्य गर्न सक्दैनौं ।त्यकारण कम्प्युटरमा काम गर्न यसमा अपरेटिङ सिस्टम राखिएको हुनपर्छ । अपरेटिङ सिस्टमले कम्प्युटर र यसको प्रयोगकर्ताको बीचमा मश्यस्थकर्ताको रुपमा कार्य गर्दछ । अपरेटिङ सिस्टमका प्रमुख कार्यहरु निम्न छनः

·        यसले स्रोतको व्यवस्थापन गर्छ ।

·        यसले प्रयोगकर्तालाई निर्देशन दिने कार्य गर्दछ।

·        यसले एप्लिकेसन प्रोग्रामहरु सञ्चालन गर्छ ।Example: Windows 95 Windows NT, Windows 98, Windows 2000, Windows ME, Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, Windows 8, Windows Server 2012, Windows 8.1, Windows 10, windows server 2016.

Advantages of using windows

·         It is easier to learn and use.

·         It allows the user to work on a number of applications simultaneously.

·         Failures to any application do not harm the computer system.

·         It has features of communicating with other computers.

·         It has many built in programs.

·         It has fast processing capability.

·         It helps to run the multiple applications at a time.

·         It is GUI based software. So every item is in graphics form.

Open source software: - The software which are freely available and no need to pay any amount to use them are called open source software. They also provide freedom to use, to modify them and to redistribute copies to others. Open Source software (OSS) is also called free software (FS). Example Linux, open office, Mozilla Firefox, Opera, Apache, Netscape etc.

Features

·        This software is freely available and no license is required to use them.

·        Source code of this software is freely in the Internet and it can be easily downloaded.

·        It has freedom at work. Everyone is free to modify the software according to their requirement from their source code.

·        There is no restriction of law to use them.

·        The OSS allows taking our own security ownership

·        By adopting open source software, we become part of a community of users and developers.

Computer virus: - A computer virus is a small malicious computer program written in any system programming language to replicate on computer and causes impediment in the normal function of the computer.

यो एक प्रकारको software हो जसले कम्प्युटर operating system मा आफ्ले बनाएको programme द्वारा कम्प्युटर मा रहेको डाटा तथा programme हरुलाई नष्ट गर्ने, रोक्ने काम गेछ त्यसलाई कम्प्युटर virus भनिन्छ ।सन् १९८८ मा सन् अमेरिकामा NASA ले कम्प्युटर virus लाई पत्ता लगाइको थियो । यसले प्रभावकारी रुपमा कार्यसम्पादन गर्नका लागि सहयोग पुर्‌याउँछ ।

Virus कसरी थाहा पाउने?

·        Computer slow हुन्छ ।

·        File folder एकभन्दा बढी generate हुन्छ ।

·        File लाई exe देखाउँछ।

·        Mouse लाई File मा click गर्दा धेरै File अथवा Folders हरु बनाउँछ ।

Symptoms of computer virus

·        Sometimes computer may not boot properly and get frequently

·        Viruses' show error message on the screen

·        Unwanted message, figure and picture can be seen on the screen.

·        It takes long time to load the program

·        It changes the size of executable file

·        It slows down the computer

·        It reduces the memory of the computer.

·        It corrupts the system data.

·        It renames all the files with different names.

·        It increases the use of disk space and growth in the size.

Computer antivirus: -Antivirus software is a type of utility used for scanning and removing viruses from your computer. While many types of antivirus programs exist, their primary purpose is to protect computers from viruses and remove any viruses that are found. कम्प्युटरबाट देखा पर्ने Virus समाधान गर्नका लागि राखिएको Software लाई Antivirus भनिन्छ ।

यसले Virus को प्रतिरोध गर्छ, Virus हटाउनका लागि सहयोग गर्छ ।

कम्प्युटरमा virus देखापरेपछि सो समाधानका लागि Antivirus Install गरिन्छ ।

Antivirus ले कम्प्युटरलाई virusबाट जोगाइ programme चालउन मद्दत गर्छ ।

Antivirus software perform the following task

1.      Scans the files or folders for viruses

2.      Alert the user when viruses are found and provide the information about viruses.

3.      Automatically cleans the virus-infected files.

4.      Monitors the resource of the computer from viruses.

Some common Antivirus software are

AVG	MacAfee	SCAN utility	Avast	eScan
Norton Antivirus	Avira	KASPERSKY	Panda Antivirus

Protection from virus

Following are the preventive measures from computer viruses

1.      Not to use pirated software.

2.      Install and update antivirus software regularly.

3.      Scan the mail and unknown file of Internet before opening the computer.

4.      Not to use computer unless the virus totally removed from the infected computer.

5.      Backup the data program on regular basis.

6.      Lock the computer when not in use.

7.      Use the password system to avoid unauthorized use of the computer.

8.      Check the new software for virus before installing it.

9.      Check the CD, pen drive etc. of other's while using.

Networking: It is the collection of computer and devices interconnected by wire or wireless that facilitate communication among users and also users to share resource (file, printer, DVD-ROM etc.) and information.

Purpose/benefits/Advantages of networking: Some of the advantages are

1.      Resource sharing: The main advantages of networking are resource sharing. Resource can be hardware and software like file, printer, operating system, scanner, hard disk etc.

2.      Communication Medium: The main goal was to established communication between autonomous devices. It is very fast and cheap to communicate long distance through network communications. We can communicate via sending text, listening online FM stations, e-commerce, Facebook.

3.      Centralized computing: All the computer and other components of a network are managed and controlled by central computer is called server. Server data can be protected easily and the data can be transferred to all the clients through server rather than individual.

4.      Simultaneous Access: Many organizations like banks works on same database system. This database should be modified, updated and deleted frequently. A network server is a central computer with large storage capacity and other resources that all users can share.

5.      Backup and recovery: The server is placed in a secure place and in a good security mechanism is providing for backup of data. If the data is lost accidently or due to any other reason in client, then it is possible to restore them from the server.

6.      Saving money: Mainframe computer are hundred times faster than personal computer. Because of this imbalance personal computer with network emerge to share data and resource through different mainframe server.

Disadvantages:

    I.          Increase Expenses: In order to install computer in network, we require some common devices such as hubs, cable, NIC, MODEM, switch, router etc. Networking equipment and network software are expensive too.

  II.           Possibility of leakage and corruption of data: The data transmission in between the nodes can be hacked and used by third parties. This causes data corruption and leakage in networking. Hackers and computer virus are the threats to the computers in the network.

III.          Need special technical knowledge: -To work in networking environment, the organization needs s very high skilled manpower to install and operate it. The absence of technical man power causes shutdown of network.

Computer network types: On the basis of geographical areas

LAN: A group of computer and other devices that are connected by communication lines in a limited geographical area such as home, campus, office building. Basically, Networks covers area up to 1 Km. LAN is faster then WAN and MAN. Twisted pair cable is the major transmission medium and in wireless radio and infrared. Ethernet is the most common used technology. विशेषतः १ कि.मि.सम्मको दूरीमा अर्थात कुनै निश्चित स्थान वा Area सम्म मात्र Network को विस्तार गरिएको हुन्छ ।

MAN: MAN is networks larger than LAN and smaller that WAN. It is called metropolitan since it normally covers the area of city or two towns up to 100 kms. Example Network of cable television.

LAN को भन्दा यसको Range बढी हुने गर्दछ। यो कुनै पनि सहर वा टूलो एलाकालाई आधार मानेर नेटवेक को विस्तार गरिइको हुन्छ । यसमा Radio Wave प्रणाली लागू गरिएको हुन्छ ।

WAN: A geographically widespread network capable for communicating and sharing all types of data and information all around the world is called WAN. It is the network of network and consists of large number of LANs and MANs. The span of WAN is in thousand KM around the world connecting countries and continents. WAN has the slowest data communication rates. The operator of WAN is by ISP (Internet Service Provider) or by Telephone Company.

मुलुकको कुनै पानि एक स्थानदेखि अर्को स्थानसम्मको अर्थात टाढाको कम्प्युटरहरुलाई जोड्नका लागि WAN प्रयोग गरिन्छ । यसको क्षेमेत्र विस्तार हुन्छ भने सञ्जाल धेरै टूलो हुन्छ । कार्तक्षमता उच्च हुन्छ । वर्तमान अचस्थामा इन्टेरनेटको प्रयोग यसै अन्तर्गत पर्दछ ।

Difference between LAN and WAN

LAN	WAN
1.      It stand for Local Area Network	1.      It stand for Wide Area Network
2.      It covers a small geographical  area like home, office, school, group of building	2.      It covers  broad area like  continent to continent
3.      High speed (100 mbps)	3.      Less speed (150 mbps)
4.      LANs have high data transfer rate	4.      WAN have lower data transfer rate
5.      Primarily  use Ethernet and token ring for connectivity	5.      Use technologies like MPLS, ATM, frame relay and X.25 for connectivity
6.      One Lan can be connected to other LANs over any distance via telephones line and radio waves	6.      Computers connected to a wide area network are often connected through public network such as telephone system, leased line or satellites
7.      Device such as switch, bridge, hub ,repeater are used	7.      Devices such as router,, multilayer switch are used
8.      lAN tends to have fewer problem associated with them, as there are smaller number of system to deal with.	8.      WANs tends to be less fault tolerant as they consists of large number of system
9.      Experiences fewer data transmission errors	9.      experience more data transmission errors as compared to LAN
10.   Typically owned, controlled and managed by a single person or organization	10.   Wan are not owned by any one organization but rather exists under collective or distributed ownership and management over long distances
11.   If there is need to set up a couple of extra device on the network, it is not very experience to do that	11.   For WAN, to set up the network, it will be costly
12.   Have a small geographical rage and do not need any lease telecommunication lines	12.   Have large geographical range generally spreading across boundaries and need leased telecommunication lines.
13.   It covers a relatively small geographical area, LAN is easier to maintain at relatively  low costs	13.   WAN is difficult because of its wider geographical coverage and higher maintenance costs.
14.   High bandwidth is available for transmission	14.   Low bandwidth is available transmission
15.   Less congestion	15.   More congestion

Server: -A server is a computer program or device that provides a service to another computer program and its user, also known as the client. In a data center, the physical computer that a server program runs on is also frequently referred to as a server. That machine may be a dedicated server or it may be used for other purposes as well. चौबीसै घण्टा इन्टरनेटमा कुनै पानि डाटा को सेवा दिने गरी राखिइको कम्प्युटरलाई सर्भर भनिन्छ । हामीले प्रयोग गर्ने सम्पूर्न बेभसाइटहरु सर्भरबाट उपल्ब्ध हुन्छन् । कृष् विकास बैक लि। online कार्यालय हरुमा data supply  गर्नका लागि central server को प्रयोग गरिइको हुन्छ । यसले चौबीस घण्टा डाटा सप्लाईको कार्य गर्दछ ।

Servers are often categorized in terms of their purpose.

• A Web server is a computer program that serves requested HTML pages or files. In this case, a Web browser acts as the client.
• An application server is a program in a computer in a distributed network that provides the business logic for an application program.
• A proxy server is software that acts as an intermediary between an endpoint device, such as a computer, and another server from which a user or client is requesting a service.
• A mail server is an application that receives incoming e-mails from local users (people within the same domain) and remote senders and forwards outgoing e-mails for delivery.
• A virtual server is a program running on a shared server that is configured in such a way that it seems to each user that they have complete control of a server.
• A file server is a computer responsible for the central storage and management of data files so that other computers on the same network can access them.
• A policy server is a security component of a policy-based network that provides authorization services and facilitates tracking and control of files.

Internet service provider (ISP) is an organization that provides services for accessing, using, or participating in the Internet. Internet service providers may be organized in various forms, such as commercial, community-owned, non-profit, or otherwise privately owned. Internet services typically provided by ISPs include Internet access, Internet transit, domain name registration, web hosting, Usenet service, and colocation. इन्टरनेट सेवा प्रदान गर्ने कम्पनीलाइ ISP भनिन्छ । यस्ता कम्पनीहरुले निश्चित शुल्क लिएर इन्टरनेट सेवा प्रदान गर्ने गर्दछन। नेपालका इन्टरनेट सेवा प्रदायक कम्पनीहरु जस्तै

This is a list of internet service providers in Nepal:

1. Vianet Communication                                                                 WorldLink Communication Pvt Ltd
2. Subisu CableNet Pvt. Ltd.                                               FIRSTLINK Communications
3. Mercantile Communication                                                          Classic Tech Pvt Ltd                                         
4. BroadBand Solutions Pvt. Ltd.                                                      Nepal Telecom ADSL Service
5. Broadlink Networks and Communication Pvt Ltd                       Loop Networks pvt.Ltd.
6. Infocom Pvt Ltd                                                                              Ultranet Communications
7. Konnect Nepal                                                                                Himalayan Online Service PVt Ltd
8. Websurfer Nepal Pvt Ltd                                                EAST LINK TECHNOLOGY PVT. LTD.
9. Otel                                                                                                  Techminds Network Pvt. Ltd.
10. Everest Link (P) Ltd.                                                                        Unified Communication Pvt. Ltd
11. Allied NetLink Technologies Pvt. Ltd.                                           Reliant Techno Networking Pvt. Ltd.

MODEM: It is a device that allows a computer to transmit information over a telephone line. The Modem translates between the digital signal that the computer uses and analog signal that telephone line carries. The process of converting digital signal in the form of 0 and 1 to analog signal is called modulation and the process of converting analog signal to digital signal in the form of 0 and 1 is called demodulation. The speed at which modem can transfer data is measures in bits per second. Most popular modems are 28 kbps or 56 kbps.

Webpage: -A web page is a document that is connected to the World Wide Web. It is visible by anyone connected to the Internet who has a web browser. The web pages are created by using a programming language called hypertext markup language(HTML). It is commonly including text, graphics and link to other webpages.

Website: - a website is a collection of webpages that are related to each other. A website is created by a web page designer for an organization to give information about business, products and services.

Home pages: -A home page is the very first page of a web site. It is the first page that a browser opens when you access a website. It acts as the gateway to the web site by providing links to its other pages.

URL (Uniform Resource Locator): - The full form of URL is Uniform Resource Locator. It is the address of a web site or web page on the internet. Each website or webpage on the internet has ab unique address.

Example

Name                                                                 URl

Supreme court Nepal                                       www.supremecourt.gov.np

Public Service commission Nepal                  www.psc.gov.np

Google search engine                                      www.google.com

National examinations board                          http://www.neb.gov.np/

Agriculture Development Bank Linited         http://www.adbl.gov.np

Rastriya Banijya Bank                                     http://rbb.com.np

Domain name system:-In a network environment, the name /address given to a single website or a computer which uniquely identifies the resources is called domain name system.

Type of domain  names

a.      Top level domain(TLD):- In an url, the first field is then host name which identifies a singlecomputer or organization. The last field of the URL is called top level domain, describingthe type of organization and services.some of the top level domain  includes

.com       commercial

.edu        educational

.gov        government

.int         institutional

.mil;       military

.net         Networking provides

.org        organizational

Country level domain: Second level domain name includes the country or the origin of the country. Second level domain comes after top level domain and separated by a period symbol. Example

.np          Nepal

.au          Australia

.fr           france

.nl           Netherlands

.uk          United Kingdom

.us          United States of America 

.in           inda      

.sg          Singapore

  

Multimedia: - Multimedia is content that uses a combination of different content form such as text, audio, images, animation, video and interactive content. The multimedia may be combined with movie, presentation, interactivity, graphics or animation to give some information which can be stored, transmitted and processed digitally. दुई वा दुईभन्दा बढी मिडियाहरुको समायोजनलाई नै मल्टिमिडिया भनिन्छ । Window operating  सँगै मल्टिमिडिया Progrmme आएको हुन्छ ।Multimedia को व्यवस्थाअन्तर्गत हामीहरु कम्प्युटरमा CD मा कपी गरिएको अडियो सुन्न तथा भिडियो इमोज हेर्ने सक्छौं ।

Components of Multimedia

·        Text: - Text is the basic element of multimedia. Text is combination of alphabets symbols, digits, punctuation etc. In a multimedia application, other media or screen can be linked through the use of text. This is what you call Hypertext.

·        Graphics(Image):- A picture is a worth of thousand words. An image, figure, picture or drawing can consider as graphics. Graphics represent still image and defined as static representation. Extensions are jpeg, gif, bmp, png, jpg etc. Common graphic software program are Photoshop, paint. Net etc

·        For example Photoshop of an employee with his/her name, sex, age, address etc from a company's database of employee's make the employee information much more effective.

·        Audio:- A multimedia application may require the use of speech, music and sound effects. These are called audio or the sound element. There are two basic types of audio or sound: analog and digital audio. Applications of audio service are telephone communication, telemarketing, voicemail, audio teleconferencing, radio etc. Audio format include MP3, WMA, Wave, MIDI and RealAudio. Soundcard, headphone, speaker, audio mixer, and microphones are used for generating audio or sound.

·        Video: - Video is the sequence of images over time. Video clips can be combined with audio, text, graphics. Video conferencing, television, multimedia, CCTV etc are application of video communication, Common digital video formats include flash, Mpeg, AVI, WMV and QuickTime etc.

·        Animation:- Animation is the displaying of image in a sequence to create an effect a visual change or motion similar to a movie (video).Image generation tools such as digital camera, scanner and video generation tools such as digital video camera, videocassette Recorder (VCR), Digital Versatile Disk (DVD) are the powerful tool for generating images and videos for animation. Common tools for creating animation are Adobe flash. Example Cartoons on television.

Services provided by internet

Video Conference: - Video conference is conduction a conference between two or more participants at different sites by using computer networks to transmit audio and video data to connect users anywhere in the world as if they were in the same room. each user or group of users who are participating in a video conference typically must have a computer, camera, microphone, a video screen and a sound system. Multipoint videoconference allows there or more participants to set in a virtual conference room and communicate as if they were sitting next to each other.

e-Business: The full form of the term is electronic business. It is the exchange of goods and services by means of the internet or other computer networks. Electronic business can occur between a user and vendor through online information services, internet or other electronic forms. The main component of transaction is just electronic data interchange. E-commerce offers buyers convenience. They can visit the website of multiple vendors 24 hrs a day and 7 days a week to compare prices and make purchases without having to heave their homes or office. Consumer can immediately obtain a product or services such as electronic books, music file, and computer software by downloading it from Internet.

E-business:- कम्प्युटर प्रविधिको प्रयोगद्वारा कुनै पनि वस्तुको विज्ञापन गर्ने, बजार प्रवर्द्धन गर्ने, बिक्री व्यवसाय गर्ने कार्यलाई e-business भनिन्छ । नेपालमा पनि बैकहरु, डिपार्टमेन्टल स्टोर, बिजनेस हाउस वा होटलहरुमा यो सुविधा उपलब्ध गराउदै आएको पाइन्छ ।वर्तमान अवस्थामा विकासोन्मुख मुलुकहरुले सहर तथा बजारीय cyber cafe, सरकारी तथा निजी क्षेत्रहरु समेत देवा दिन थालेका छन् ।आजकल मुलुकको विभिन्न ग्रामिण इलाकाका उत्पादनहरु जस्तै आलु, लसुन, चामल आदि web-page हेरी email मार्फत मर्फत मगाउने र e-banking मार्फत बिलको भुक्तानी गरी बिक्री वितरण गर्न थालिएको छ। वर्तमान विश्वव्यापीकरणको युगमा e-business अपरिहार्य वस्तु हो ।

Different types of e-Business

                            i.          Business To Business (B2B)                                                            iv.           Business To Consumer(B2C)

                          ii.          Business to Government(B2E)                                                      v.            Government-To-Government(G2G)

                         iii.          Government-To-Citizen (G2C)                                                      vi.           Government -To- Business (G2B)

Application

1.      Voice over Internet Protocol (VoIP)          3.Voice mail               5. Web conferencing    

2.      Internet shop                                                         4. Online marketing

E-governances( विद्तिय शासन): It is the use of information and communication technology to transform the traditional government by making it easily accessible, transparent, effective and accountable to the general people. It is a network of organization to include government, nonprofit and private-sector to transform all services in the form of electronically. It established a relationship between government and citizen. E-governance provides greater access to government information and services by making the most of the government services online.

Example: http://www.nepal.gov.np/, where citizen have access to variety of information and services.

Advantages

1.      It is easy to access data and information.

2.      It become one portal for delivery government services

3.      It handles Government To Government (G2G), Government To Business (G2B), and Government to Citizen (G2C) data and information services.

4.      The government service will be made available to the citizen in a convenient, efficient and transparent way.

5.      There will be no territory boundaries to access information and services.

राज्य संचालन कार्यमा नीति निर्माण,योजना तर्जुमा, कार्यान्वयन अनुगमन र मूल्यांकन क्रममा, Information Technology को प्रयोग  गरी व्यवस्थित, वैज्ञानिक र आधुनिक ढगबाट राज्य सञ्चालन गरिने पद्धतिलाई विद्तिय शासन भनिन्छ ।

फाइदाहरु

ईमेल इन्टरनेट सेवा लिन सकिने

कार्य सम्पादनमा सुधार हुने

भौगोलिक दूरीको अन्त हुने

सरकार तथा नागरिकको सर्चामा व्यापक कटौती हुने

सूचनाकोहकको प्रवद्धन हुने

पारदर्शी शासन  व्यस्थाको आत्मसात् हुने

विश्वसनीय तथ्ताक एवं सूचना  उपल्ब्ध हुने

भ्रष्टाचार नियन्त्रण हुन गई राजस्वमा वृद्धि हुने

बिभिन्न पक्षहरुबीच सम्न्वय कायम गर्न सजिलो आउने

ढिलासुस्ती न्यूनीकरण बई कार्य सम्पादन सहजता आउने

न्यून जनशक्ति,न्यून लागतमा अधिकतम पर्तिफल प्राप्त गर्न सकिने

सेवा छिटो छरितो एवं सरल ढंउबाट प्रवाहित हुने

सुशासनको प्रत्याभूति एवं दिगो समृद्धि हासिल हुने ।

Email: - Email address is also called e-mail ID. It is the location of the personal mailbox in the internet, each person has unique email address in the internet. An email address has two parts : username and hostname. Started in 1976 A.D from USA.

General form at of email  address is username@hostname

Example: santoshs.poudel@gmail.com, here santoshs.poudel is username and gmail.com is the hostname. Th hostname is the name of email server which is providing email services.

Emal account:- email account is a valid identification name or ID autroized user provides by ISP or created using any of the email program. An email contains username, domain name,@sign,domain type and country code. Some popular website that provide free email service are www.yahoo.com, hotmail.com, gmail.com

History of Internet: Begins as ARPANET in 1969 by US Department of Defense Research project Agency (ARPA)

Link many universities and research centers

First two nodes that formed ARPANET were UCLA and Stanford Research Institute.

Network set a protocol to create an effective way for people to communicate and shared data with each other.

In 1980 National Science Foundation (NFS) linked several high speed computer and change what is known to be Internet

By late 1980's thousands of cooperation network were participating in the Internet.

In 1991, National Research & Education Network developed and maintain high speed network for research and education and to investigate commercial used of the Internet.

Services provided by internet

Video Conference: - Video conference is conduction a conference between two or more participants at different sites by using computer networks to transmit audio and video data to connect users anywhere in the world as if they were in the same room. each user or group of users who are participating in a video conference typically must have a computer, camera, microphone, a video screen and a sound system. Multipoint videoconference allows there or more participants to set in a virtual conference room and communicate as if they were sitting next to each other.

Telnet: -Telnet is a network protocol that allows a user to connect to remote computers over a TCP/IP network such as Internet. Through telnet. an administration or another computer that is part of the same network. Telnet clients awe available for all major operating system such s Mac OS, Windows, UNIX and Linux.

Chatting: - Chatting allows users to talk to another in virtual real time. It is the team time type conversation via computers. That means you can only caht with those people who are currently online. Users communicate by typing messages which are send instantly to another person or group. Example yahoo messanger, MSN messangerprograms.

News group: - a newsgroup is a discussion about a particular subject consisting of noted written to a central internet site and redistributed through usenet. The usernet is a world wide network of news discussion groups, usenets uses the network news transfer protocail NNTP . a etrs group is the online area in which users con duct written discussion about a particular sub ject, users can pist tom exists g netrs goups, respond mt previous posts andcreate new groups.

Negative impact of Internet

Piracy: - computer related technologies are used for copying, distributing (pirating) software, movie, music, books without permission. Internet is one of the main source of the pirating.

Pornography:-Internet is the main source of pornography. It is the process of viewing adult content like text, image or video.

Theft: - There is a chance of transferring the money from one's account to another's account by hacking password, PIN code etc. Computers and internet also used for stealing valuable information of companies, government organizations etc.

Digital digital: - It is the gap of imbalance of the people, households, business and geographical area who use computer and internet and the people, households, business and geographical area who do not use computer and internet.

Many things such as differences in income, education, geographical location, development, infrastructure, policy of the government, comfort levels with technology are contributing factors to create digital divide by making the separation between those with access to technology resources and those without.

Digital divide is the problem that has been created due to unbalance economic status in the society and if the government does not take appropriate policy it will be widen day by day and may cause a huge problem in coming days.

Digital divide effects the modern society

1.      Economic imbalance

2.      Communication gap

3.      Physical barriers

4.      Lack of awareness about information and technology.

Spamming: - Spamming is the sending of unwanted and useless emails to random people. These emails construct the recipients needlessly. They are illegal and make it hard for people to access their email accounts.

Plagiarism: - It is defined as the copying of another authors language, thoughts, ideas or expression and represent them as own purpose. Internets are used to copy the other person's arts, notes, ideas for own purpose.

Personal information: - If you use the internet, your personal information such as your name, address etc. Can be accessed by other people.

Intranet: - An internet is a private network within an organization, offices, universities etc. to its staff, employees and students that uses protocols and makes connectivity with internet system. आफ्नो आन्तरिक कार्य प्रणाली सञ्चालनको लागि कुनै बैक तथा वित्तीय संस्थाले आफ्नो स्वामित्वमा मात्र कायम हुने गरी स्थापना गरिएको Private network लाई Intranet भनिन्छ ।

Usages of Intranet

To deliver tools.

Management productivity quality and corporate issue.

Larger business man को प्रयोग नगरिनु

Management in formation system को लागि

Intranet user-experience editorial and rechnology tema work together to produce in house sites.

Advantages of Intranet: -

• Workforce productivity: It help users to locate and view information faster and use applications relevant to their roles and responsibilities. With the help of a web browser interface, users can access data held in any database the organization wants to make available, anytime and — subject to security provisions — from anywhere within the company workstations, increasing the employee's ability to perform their jobs faster, more accurately, and with confidence that they have the right information. It also helps to improve the services provided to the users.
• Time: Intranets allow organizations to distribute information to employees on an as-needed basis; Employees may link to relevant information at their convenience, rather than being distracted indiscriminately by email.
• Communication: Intranets can serve as powerful tools for communication within an organization, vertically strategic initiatives that have a global reach throughout the organization. The type of information that can easily be conveyed is the purpose of the initiative and what the initiative is aiming to achieve, who is driving the initiative, results achieved to date, and who to speak to for more information. By providing this information on the intranet, staff have the opportunity to keep up-to-date with the strategic focus of the organization. Some examples of communication would be chat, email, and/or blogs. A great real-world example of where an intranet helped a company communicate is when Nestle had a number of food processing plants in Scandinavia. Their central support system had to deal with a number of queries every day.^[7] When Nestle decided to invest in an intranet, they quickly realized the savings. McGovern says the savings from the reduction in query calls was substantially greater than the investment in the intranet.
• Web publishing allows cumbersome corporate knowledge to be maintained and easily accessed throughout the company using hypermedia and Web technologies.^[8] Examples include: employee manuals, benefits documents, company policies, business standards, news feeds, and even training, can be accessed using common Internet standards (Acrobat files, Flash files, CGI applications). Because each business unit can update the online copy of a document, the most recent version is usually available to employees using the intranet.
• Business operations and management: Intranets are also being used as a platform for developing and deploying applications to support business operations and decisions across the internetworked enterprise.^[8]
• Workflow - a collective term that reduces delay, such as automating meeting scheduling and vacation planning^[9]
• Cost-effective: Users can view information and data via web-browser rather than maintaining physical documents such as procedure manuals, internal phone list and requisition forms. This can potentially save the business money on printing, duplicating documents, and the environment as well as document maintenance overhead. For example, the HRM company PeopleSoft "derived significant cost savings by shifting HR processes to the intranet".^[7] McGovern goes on to say the manual cost of enrolling in benefits was found to be USD109.48 per enrollment. "Shifting this process to the intranet reduced the cost per enrollment to $21.79; a saving of 80 percent". Another company that saved money on expense reports was Cisco. "In 1996, Cisco processed 54,000 reports and the amount of dollars processed was USD19 million".
• Enhance collaboration: Information is easily accessible by all authorised users, which enables teamwork.^[8] Being able to communicate in real-time through integrated third party tools, such as an instant messenger, promotes the sharing of ideas and removes blockages to communication to help boost a business' productivity
• Cross-platform capability: Standards-compliant web browsers are available for Windows, Mac, and UNIX.
• Built for one audience: Many companies dictate computer specifications which, in turn, may allow Intranet developers to write applications that only have to work on one browser (no cross-browser compatibility issues). Being able to specifically address your "viewer" is a great advantage. Since Intranets are user-specific (requiring database/network authentication prior to access), you know exactly who you are interfacing with and can personalize your Intranet based on role (job title, department) or individual ("Congratulations Jane, on your 3rd year with our company!").
• Promote common corporate culture: Every user has the ability to view the same information within the Intranet.
• Immediate updates: When dealing with the public in any capacity, laws, specifications, and parameters can change. Intranets make it possible to provide your audience with "live" changes so they are kept up-to-date, which can limit a company's liability.
• Supports a distributed computing architecture: The intranet can also be linked to a company’s management information system, for example a time keeping system.
• Employee Engagement: Since "involvement in decision making" is one of the main drivers of employee engagement, offering tools (like forums or surveys) that foster peer-to-peer collaboration and employee participation can make employees feel more valued and involved.

Planning and creation of the intranet

·        Most organizations devote considerable resources into the planning and implementation of their intranet as it is of strategic importance to the organization's success. Some of the planning would include topics such as determining the purpose and goals of the intranet,^[13][14] identifying persons or departments responsible for implementation and management and devising functional plans, page layouts and designs.^[15]

·        The appropriate staff would also ensure that implementation schedules and phase-out of existing systems were organized, while defining and implementing security of the intranet and ensuring it lies within legal boundaries and other constraints. In order to produce a high-value end product, systems planners should determine the level of interactivity (e.g. wikis, on-line forms) desired.

·        Planners may also consider whether the input of new data and updating of existing data is to be centrally controlled or devolve. These decisions sit alongside to the hardware and software considerations (like content management systems), participation issues (like good taste, harassment, confidentiality), and features to be supported.^[16]

·        Intranets are often static sites; they are a shared drive, serving up centrally stored documents alongside internal articles or communications (often one-way communication). By leveraging firms which specialise in 'social' intranets, organisations are beginning to think of how their intranets can become a 'communication hub' for their entire team.^[17] The actual implementation would include steps such as securing senior management support and funding.,^[18] conducting a business requirement analysis and identifying users' information needs.

·        From the technical perspective, there would need to be a co-ordinated installation of the web server and user access network, the required user/client applications and the creation of document framework (or template) for the content to be hosted.^[19]

·        The end-user should be involved in testing and promoting use of the company intranet, possibly through a parallel adoption methodology or pilot programme. In the long term, the company should carry out ongoing measurement and evaluation, including through benchmarking against other company services.^[20][21]

• Password Management - Rather than have a Password manager manage two or more dozen passwords,^[9][22]Single Sign-on (SSO) allows a single password to cover multiple applications. This is a relatively new development.

·        Advantages of intranet

·        Easily share information

·        Most companies use email as the primary method of disseminating important company information. But did you know the average employee checks their email roughly 36 times a day? That’s a lot of distraction. Sharing information where your employees already are means less context switching and less wasted time. Try sending out information through your company’s intranet for company-wide announcements.

·        On the homepage of Atlassian’s intranet, everyone has access to the posts being shared, the conversations happening (FOMO no more), the teams involved, and anything else trending in the company.

·        Knowledge management

·        No matter where you work, your company has a lot of information to store. In most cases, knowledge is stored across multiple platforms like email, Word documents, Google Drive, etc. making finding information a tedious task. Instead, using your intranet as a central one-stop shop for all information means it will be easier for your employees to find what they need. It’s important your intranet has strong search capabilities so teams can quickly locate relevant information.

·        Teams like HR and Legal often use intranets to host on-boarding material, employee benefits, HR guidelines, and legal policies, but why stop there? Any team can and should use it to keep knowledge accessible.

·        Improve collaboration and feedback

·        The best way to encourage employees to use your intranet is to pull them in. People will naturally use a tool when they are drawn in by their peers or their work. Most intranets have social features such as @-mentions, comments, easy document sharing, and some form of notifications. Using mentions and comments help you bring in the right people at the right time to contribute to work, and keeps all feedback and contributions contextual.

·        A well-rounded intranet allows real-time page editing with teammates and tasks assignments with deadlines.

·        reate engaging content

·        There’s a common saying that “people eat with their eyes.” The same can be said about content on your intranet. When content looks good, people are more likely to want to read it.

·        A good intranet makes it easy to create engaging content of any type, whether it be a blog post, meeting notes, a marketing campaign plan, or product requirements. Can you imagine trying to format and share that kind of information in an email using a basic editor and bullet points? Not many would opt into reading that. Using templates and a feature rich editor should empower your team to make pages they are proud to share – easy peasy.

·        Build a transparent culture

·        In order to bring out the best in your employees, you need to create a space they can feel comfortable sharing thoughts and opinions. Did you know that 87 percent of people want to work for a transparent company? I‘m sure by now you’ve guessed an intranet can be the ticket to building a transparent company.

·        At Atlassian, one of our strongest assets is our company culture, built on the principles of transparency and open work. Confluence, our intranet and everyday workspace, plays a critical role in who we are as a company and how we choose to work with one another. Anyone can contribute, like, and comment on anything shared within the company, allowing for transparency between execs and all employees. We have teams located all around the world, from Sydney, Australia to Austin, Texas, and when we are able to share bits and pieces of ourselves, whether it’s a piece of advice we want to blog to the whole company about or congratulating a team member on a promotion, our team of more than 2,500 people feels a lot smaller.

·File sharing and document management

·Personalised news feed

·Automated business processes such as online forms

·Project workspaces

·Employee directories, including skills and contact information

·Digital workplace

Extranet: - It is the combination of intranet and internet which can be accessed by outside users over the internet by logging on to the networks with a valid user ID.

Advantges

·        Exchanges large volumes of data using electronic data interchange(EDI).

·        Share product catalogs exclusively with trade partners.

·        Collaborate with other companies on joint development efforts.

·        Jointly develop and use training programs with other companies.

·        Provides or access services provides by one company to a group of other companies such as an online banking application managed by one company on behalf of affiliated banks.

Disadvantages

·        Extranets can be expensive to implement and maintain with in an organization (eg hardware, software, employee training costs). If hosted internally rather than by an application services providers.

·        Security of extranets can be a concern when hosting valuale or proprietary information.

Internet	Intranet
It is public global network	It is a private network
It is independent to access and use resource itself.	It is dependent to the internet protocol to communicate and access information.
It suns slower that intranet	It runs faster than internet
Internet users are unlimited all over the world.	Intranet users are limited as employees within  an organization
It is used for all kinds of works	It is used for daily routine works

Cyber law deals with Internet hacking, pornography, cyber-stalking, cyber scams, online fraud, and software piracy and much more.

In many countries, Cyber law exists in the name of Information Technology Law (IT Law). It is a set of recent legal enactments, which governs the process and dissemination of information digitally.

Computer Crime: It is the illegal use of a computer by an unauthorized individual, either for pleasure such as by a computer hacker or for profit as by thief. Thus it refers to any crime such as tampering, physical danger, unwanted disclosure of data that involves a computer and a computer network.

For example: a personal computer connected to the Internet without protection may be affected with malicious foteare within a minute

efax may refer to:

·        Internet fax, the transferral of fax information using the Internet

·        efax (software), a computer based fax program for Unix-like computer systems

·        Everett Efax file format, a file format

Information technology (IT) is the application of computers and telecommunications equipment to store, retrieve, transmit and manipulate data, often in the context of a business or other enterprise. IT is considered a subset of information and communications technology (ICT). Business/IT was one level of the ICT hierarchy.

The term is commonly used as asynonym for computers and computer networks, but it also encompasses other information distribution technologies such as television and telephones. Several industries are associated  with information technology, including computer hardware,software,electronics,semiconductors,internet,telecom equipment,engineering,healthcare,e-commerce and computer services.

·        Increases production and saves time: Business use technology to automate tasks.  A good example is a bakery which uses automated temperature censors to detect any drop or increase in room temperature in a bakery. These censors will send information directly to the operator and report any temperature change. This saves the bakery time and it also results into quality products.

·        Improves communication through communication technology: With the help of communication technology tools like phones, video conferencing, electronic mail, databases just to mention but a few. Movement of information with in an organization or business has become easy and first. Employees can easily move information across departments without having any interruptions. Tools like electronic mail, e-fax, mobile phones and text messaging enhance the movement of information among employees, customers and business partners or suppliers.

·        Improves data storage and file management: Businesses use cloud hosting services to store and backup business data. Also it saves on paper work and makes transfer and access of data remote. With services like ‘’Dropbox.com’’, business owners can access their data any time any where. Information and data are very important tools for a business, so it is very essential to store them safely and also access them at any time of need.

·        Improves financial management: Accounting software like Quick Books, Bookkeeper, Sage 50, and Account Edge  can be used in performing various accounting tasks in a business. Business owners can easily balance their books with less experience in accounting because this software’s are well equipped with every tool needed in accounting and they also have a help section which can be referred to in case a user is stuck.

·        Cuts costs of operation and increases on RIO – Communication technology and social technology have made business promotion and product launch affordable. Many small businesses have found ways to use social technology to increase on their brand awareness and get more clients at a minimal cost. In business, factors like cost of operation play a big role in the development and growth of that business. So when businesses use information technology to cut down on costs of operation, then their ROI will increase which will result into business growth.

·        Improves business to consumer relationship – Businesses have embraced the social technology to interact with their consumers and fans. This creates a strong business to consumer relationship and it results into business growth and expansion. Information technology can be used to improve customer service in so many ways. For example, businesses can use internet to inform their customers about great deals and discounts, this makes customers feel special and it can drive their desire to buy. A good customer service can be used as a great tool by any small business to gain competitive advantage.

·        Improves on business competitive advantage: Companies have used technology to gain competitive advantage over their competitors.  A business will improve on its technology and improve on its services and products which will make its customers happy, this will turn these happy customers loyal to that business and also invite more friends to use that service or product.

Disadvantages

·        Implementation Expenses:  Small businesses fail to afford this expensive technology so they end up losing their clients to a business which has improved its technology and provides a better service or product.

·        Job Elimination: Technology has replaced most positions which humans used to occupy. Accounting is now being done by software, so accountants run out of opportunities.

·        Security Breaches:  Since businesses store their data on remote cloud servers which can be accessed with a user name and password, they risk losing that data to wrong minded knowledge works, hackers or viruses, which can harm the business.

·        Internet security issues:  For the merchant to process an order online, a consumer has to provide their financial details. Experienced hackers can use this lop hole to channel this information and use it for their own needs.

·        Faulty products and duplication: In most cases auction websites have products that are not real. So a user can bid on a shoe thinking it is original, upon delivery, they discover that the shoe is fake and it does not resemble the picture on auction.

·        Privacy – ecommerce websites collect personal data using cookies to know more about us and suggest products basing on that information. This data is collected without any notice, but with selfish intent.

·        Over dependence on information technology makes students less active and innovative. Students no longer take time to solve equation and tasks, all they do is query that task in a search engine and a solution will be provided.

·        Poor publications online: This exposes student’s t wrong information which results into failure of exams. Many online publishers post content for monetary purposes, so you find that most the content published online is not well detailed to help students and researchers.

·         

Difference between CUI and GUI Operating System

CUI Operating System	GUI Operating System
1.      The appearance may not be as good as that of GUI	1.      The appearance of GUI is very attractive
2.      It is generally 8 or 16 bits operating system	2.      It is generally 32 or 64 or 128 bits operating system
3.      They are single user, single task OS.	3.      They are multiuser, multitask OS.
4.      Example MSDOS, PC DOS	5.       Example windows, UNIX, Linux

Firmware: -Firmware is programming that's written to the read-only memory (ROM) of a computing. Firmware usually cannot be modified during normal operation of the device. Example devices containing firmware are embedded system device such as traffic lights, consumer appliances and digital watches, mobile phones, digital cameras

Backup: - This tool allows to make reserve or extra copy of data, file, program etc. which can be restored later in its original location when they are deleted or not available.

Global village: - the world considered as a single community linked by telecommunications.(विश्व सानो गाऊँ जस्तो भएको)

Data: Data is the known facts and figure about a person, place, event or things which can be record in the form of number, text, picture, audio, video, etc. Example:  Santosh Sharma poudel,  Data is processed to produce meaningful and useful information

Information: Information is the processed value which we get after processing data by the computer. Information is very important and useful to us to make right decision at right time. Database system provides us the right information by processing the collected data in the database.

Concept of Database

Database and database systems have become an essential part of our everyday life nowadays. Example of database are preparation of census record, preparation of result sheet, deposit and withdrawal from bank, airline reservation, accessing computerized library, purchase item from supermarket etc. in all these case databases are used.

Data Management

Two types of data Management

1.      File Management Systems                                             2. Database Management System

Flat file or file based system

Before the database system has come in use, people used to keep records in file based or flat file system. The flat file based system works well when the no of records is small and there is not necessity for cross-referencing and processing of information in the file.

Example Quark X, Excel

Limitation of flat file system

I.          Inconsistent data	II.          Duplication of data.
III.          Data dependence	IV.          Incompatible file formats
V.          Fixed queries	VI.          Speed of operation is slow

Database:  A database is an organized collection of logically related data that contain information.

Database: A database is an organized collection of related data where data can be known facts and figure about person, place, event or things. For e.g. phone diary, result sheet. Database contains only data not information so it should be analyzed to get required information.

The database is called is also called repository or container for a collection of data file.Example: - University database maintains information about students, courses, and grade.

 So, database is a collection of tables, views, index, other object to serve a specific purpose such as searching, sorting, recombining data etc. in computer system

Database Management System: A general-purpose DBMS is a software system designed to allow the definition, creation, querying, update, and administration of databases. In other words, it is a set of computer software or program used to control the reading and writing of data from and to a database.

Oracle, Microsoft SQL Server, DB2, MySQL, dbase, MS-Access etc. are DBMS software.

Database Management System that maintains relationship between multiple data file is called relational database Management System (RDBMS).

Advantages of database over flat or file based system

1.      Reduction of data redundancies	2.      Shared data
3.      Data independent	4.      Improved integrity
5.      Efficient data access	6.      Multiple user interface
7.      Improved security	8.      Improved backup and recovery
9.      Support for concurrent transactions	10.   Unforeseen queries can be answered

Functions of DBMS

The major functions of DBMS are as follows:

1.      Creating database file: The creation of database file involves in naming the database file and determining the required table, field type, field width etc.

2.      Entering database record: Database application is used to insert records in the database file by checking the redundancy and validation of data.

3.      Sorting the database records: DBMS is used to sort the records on the basis of numerical or alphabetical in ascending or descending order.

4.      Deleting records: DBMS is used to delete the unnecessary records from the database.

5.      Updating records: DBMS is used to modify the existing records according to the requirement of the users.

6.      Searching records: DBMS searches the specific record according to the users need.

7.      Merging database file: DBMS is used to merge the records from two different files into a single database file.

8.      Copying records: It is used to make duplicate copy of the complete database or copying only required records to the next database file.

9.      Printing reports: DBMS is used to print the required records for reports.

10.   Backup database: It is used to back up the database for the recovery of the database from the accidental data loss or corruption.

11.   Provide security to data: DBMS protects the data in the database from unauthorized access or modification.

Objective of DBMS

       I.          Making access to the data easy for the user.

     II.          Provide quick response to the user’s request for the data.

   III.          Making the latest modification to the database available immediately.

   IV.          Eliminate redundant (duplicate) data from the database.

     V.          Allows multiple users to share the database at one time

   VI.          Allows the growth of database system.

 VII.          Provide data security by protection the data from physical harm and unauthorized access.

Types of Database Model: Various types of database models are as follows

A)    Hierarchical Model: It is one of the oldest database models. This model arranges the files used in the database in top-down structure which is similar to an upside-downside tree.

Advantages

a.      It is easiest model of database.

b.      Searching is fast and easy if parent is known.

c.      This model is very efficient in handling ' one-to-many 'relationship.

Disadvantages

1. It is old and outdated database model.
2. Modification and addition of the child node is very hard. Hence, it is non-flexible database model.

3.      It can't handle 'many-to- many' relationship.

Fig.  Hierarchical Model

B)     Network Model: In this model, each child can be linked with more than one parent. So the records can be accessed from more than one parent, which are linked. This model is more flexible and has multidimensional connection.

                                             Fig. Network Model

Advantages

1.      More flexible than hierarchical model.

2.      Reduces data redundancy because similar data is not stored in more than one file.

3.      Searching is faster because of multidimensional pointers.

Disadvantages

1.      It is very complex to design

2.      Needs long program to handle the relationship.

3.      Pointer, need in the database, model increase overheard of database storages.

4.      Less Security model because data can be accessed from any parent.

C)     Relational Model: The relational model uses a collection of table to represent both data and relationships among these data. In relational model, data are organized into table (i.e. rows and columns). These tables are called relations.Rows of relations are generally referred as tuples and columns are referred as attribute. A row in a table represents a relationship among set of data values.

Advantages

1.      Since one table is linked to other tables with some common fields, rules implemented on one table can be easily implemented to another table.

2.      Referential integrity can be easily implemented.

3.      The database has very less data redundancy.

4.      Normalization of database is possible.

5.      Rapid data processing and searching is possible.

Disadvantages

1.      It is more complex than other model due to relationship (link) with other tables.

2.      Too many rules make the database not very user-friendly.

Key terms used in Relational Database Model

I.RDBMS: It stands for Relational Database Management System. The database system which is used to manage and manipulate the data in the relational database model is called RDBMS. RDBMS stores the data in different tables and relationship between the tables can be formed by using common field (Column).

Advantages: Reduces data redundancy.

It support client-server technology where data is stored in the server and it is shared with multiple client at same time.

Example: SQL Server, MySQL, Oracle

D)            Entity Relationship Model (E-R) Model: It is a graphical representation of entities and relationship in a database.ER model is a logical structure developed to facilities database design.

ER model has 4 components

Entity: An entity is an object or things in real world such as person, car, house, employee, university etc. Example: The student id 1V7001 uniquely identifies a particular student in such organization. The complete set of fields or columns is called entity instance.

Entity identifier: An entity has an attribute whose values are distinct for each individual entity. It is done using primary key or unique constraints in a table.

Example Student ID

Relationship: A relation is a link or association between two or more entities in a database. These should be a common field between the two entities for relationship and is established by linking the foreign key in a child table with primary key in a master table.

Example:  relation between teacher and student entity। Relationship कायम गर्ने क्रममा जुन टेबलबाट relationship startगरिन्छ त्यो master table भनिन्छ भने जुन table मा relation अन्त गरिन्छ त्यो table लाई child table भनिन्छ । Relationship को क्रममा master table मा भने primary key भएको field हुनैपर्छ ।

There are three types of relationship

                 I.          One –To- one relationship: If one instance of an entity is related with one instance of another entity.

Example: The relationship between college entity and principal entity.  कुनै २ टेबलबीच relationship  कायम हुने field मा primary key assign भऐको छ र उक्त field हरु बीच हुने relationलाई  One –To- one relationship भनिन्छ ।

               II.          One- To-Many Relationship: If one instance of an entity is related with many instance of other entity. Example: The relationship between college and student entity as one college has many students.

Relationship start हुने table को field मा primary key हुन्छ र relationship end हुने field मा primary key हुदैन। यस्तो relationship लाई one to many relationship भनिन्छ ।

             III.          Many -To- Many Relationship: If many instance of one entity are related with many instance of another entity.

Example: Teacher entity and student entity consider as many to many relationships. यस रेलेसनका लागि कम्तीमा पनि ३ वटा टेबलको आवश्यकता पर्दछ । ३ वटा टेबल मध्ये पहिलो टेबलको relation दोस्रो टेबलसँग One- To-Many को relation कायम हुनुपर्छ भने तेस्रो टेबलको relation दोस्रो टेबलसँग One- To-Many कायम भइको हुनुपर्छ ।

Data Security: Data security is the method of keeping data protected from corrupted, modification by unauthorized user, leakage and physical harms. Data plays very important roles to give right information, decision and planning at right time. So, data must remain correct and unchanged and for this privacy must be adopted to make the data secure.

Method of data securities are as follows

1.      Regular backup of database in disk, tapes, optical disks etc. in order to prevent from accidental loss.

2.      Using password to login in system to prevent data from unauthorized access to the database.

3.      Specifying the specific roles to every user of the database for granting the appropriate permission to them.

4.      Making physical prevention by using stabilizer and UPS to supply a regular power through which we can prevent hardware and software from high electricity voltage and irregular power supply.

5.      Keeping the system in safe room or place with lock and key or under the supervision of watchman to prevent from theft.

6.      Implementing software protection like antivirus, firewalls, antispyware, etc.