Magnetic Tape

Magnetic Tape is a secondary sequential storage media. Magnetic tape has also been used for years as an input or storage mediium and remains a choice today for high speed, large volume storage. Its data density is high, and it transfer rate is comparatively fast.The tape itself may be in a large reel or a smal cartidge or cassette. However packaged , the tape is usually similar to the kind used in tape recoder. It's a plastic ribbon that is coated on one side with iron oxide or some other material that can be magnetised. Tiny invisible spots representing data are recorded by electromagnetic pulses on the coated side of the tape.
Magnetic tape has a read head for reading the information stored on the tape,i.e. for transferring data from the tape into main storage . The tape moves past the read head at a speed of 200 inches per second.It is 0.5"wide and may be 50 ft.,100ft.,200ft.,400ft.,600ft.,1200ft.,2400ft.,long. There are 7 or 9 tracks depending upon the tape unit, which run the length of the tape. The data is coded so that the one character is recorded across the 7 or 9 tracks. The capcity of tapes having 9 tracks is 33% more than 7track system of the same length.Tape recording is sequential recording and if 10000th record is to be read, it has to read all 9999 records unnecessarily which is the one of its disadvantages. In case of floppy disk or hadr disk, the records are randomly acessed and time required to acess is less, compared to the tape unit
ADVANTAGE

• Magnetic tapes can be reused .
• Mass data storage in magnetic tape is cheaper.
• Data can be stored for long term retieval purpose.
• Data can be trasferred directiely into hard disk from magnetic tape.
  DISADVANTAGE
• Data cannot beread or written on magnetic tapes without electronics devices.
• Magnetic tapes are sensitive to dust, smoke, magnetic feild, heat, etc and data are damaged or lost.
• Since they are sequential strorage media, the access os data is relatively slow as the device has to read all the data before a point or access.

CD ROM(Compact Disk Read only Memory)

CDROM is also called optical disk. An optical Disk storage system consist of rotating disk, which is coated with thin metal or other material that is highly reflective. Foccusing a laser beam or the surface of the spining disk which does data recording. The laser bam is turned on and off at a varying rate because of which tiny holes or pits are burnt into the metal burnt coating of the the disk alongthe tracks. In order to read the stored dataa less powerful laser beam is focussed on the surface. This beam isstrongly reflcted by the coated surface and weakly reflected by the pits producing pattern of on/off reflection that can be converted into electronic signals.

The storage density of optical disks is enormous, the storage cost is extermly low and the access time is relatively fast. one small inexpensive disk will able to replace 25 to 30 reels of magnetic tapes and any data on the disk can be accessed within a few milliseconds. Hence it is particularly suitable forb the archival storage of vast amount of data. Typical application are image processing, geological survey data, medical publishing indexes, historicalinformation files, etc. A serious short coming of current aviable optical disk system is thatd they are permananent storage device. Data once recorded cannot be erased and hence cannot be reused. The diameter of CDROM was 12 cm, weight 18gm and 1mm thick which has reduced to 51/4" in diameter. CDROMs are popular to store sound motion , video pictures , three dimensional pictures, graphics etc. New modification of CDs are WORM(write once read many), DVD(digital verstiale disc), RW(Read and write).

ADVANTAGE

• It is mass storage media for sound motion video, graphics, etc
• It is cheap storage media.
• The data can be stored for long time(20years)
• easy to exchange in a CD drive.
• It is reliable and economic media.

DISADVANTAGE

• Data access time is more in CDROM than hard disk
• ONce data is stored, they can't be changed.
• Only final refined data are stored in the CDROM.

MOBILE

Mobile is a movable device made by martin copper. Mobile can be divided into two parts hardware and software. Therefore, hardware consist of electronics and mobile parts. Electronics consist of current, voltage, resister, capacitor, diode, coil, transformer and transistor. Mobile is a comunicating device, it is wireless communication.

INTRODUCTION OF MOBILE PHONE
Philips lasis dicovered the principle of telephone in1816. Alexander Grahm bell invented the telephone in 1876. Galieno marconi demonstrated wireless telography in 1895. Jhon baird transmitted TV signal across atlantic in 1920. Martin copper is the father of mobile phone.
GENERATION OF MOBILE
Mobile is generated into four generation.
FIRST GENERATION

• It is heavy and compatible in size.
• They were half duplex.
• Valve were used.
• There is no more features only talking.
• It is out of date.
  SECOND GENERATION
• It is lighter than first generation
• It consist of many features mainly SMS(short measaging service).
• Both alphabatic and numeric were used.
• It consist of small B/W(black & white) picture and smileys.
• It ws full duplex.
• It consist of monophonic ringtone
  
  THIRD GENERATION
• It consist of more feature than second generation.
• It had MMS feature(Multimedia messaging service).
• It had colour picture video clip, vidieo chating etc.
• It had poly phonic ringtone as well as internet facility such as WAP(wireless application protol), GPS(general packet radio service), EDGE( Enhanced data rate for Global evolution).
• It had one more faciclities i.e. data transmission.
  
  FOURTH GENERATION
• It will be 3 to 5 times faster than Third generation.
• It is expected that it will be launched till 2010.
  CELL PHONE
  CELL PHONE is the phone which is connected with the radio signals without any wire. cell phone is developed from cellular technology. cellular technology can be divided into two parts i.e. GSM(global system of mobile communication) & CDMA ( code division multiple acess).
  GSM(Global system of mobile communication)
• It is used for first time technology.
• SIM card is used in this technology.
• IME number is used.
• Mobile number is free from the set.
• It consist of many bands such as 850/900/1800/1900 MHz.
• In nepal for NTC 900MHz & for Mero 900/1800 MHz
  CDMA(Code division multiple Acess)
• No SIM card is used n this technology.
• ESN(Electronic serial number) is used.
• Mobile number is included with the set.
• In Nepal UTL(United telecom limited) and Sky are providing CDMA.
  ADVANTAGES
• It has high network power.
• It cost low and gives high performance.
• It has long life battery.
• If the set is stolen or missed, It can be found easily
  In some CDMA, extrnal is used which looks like SIM that is called R-UIM (Removable user interface module)
  

HISTORY OF COMPUTER IN NEPAL

It took nearly 6 years and 6 months to prpare census report fo Buerau of Statistics for the census conducted in 2018 B.S. by using a calculating device called Facit. Total population at that time was only 96 lakhs. Due to the delay in census calculation, the five year planning was stopped and it could not give the exact figure of population in different districts. For better and quicker dta processing , Government brought IBM 1401on rent(Rs 1lakh 25 thousand per month) for the census of 2028B.S. The machine took 1 year 7 months and 15 days for the processing of 1 core 12.5 lakhs population . TH is machine, however, was not sent back to the owner and government purchased it for further data processing in the Bureau of Statics . For the proper use of the computer and continuous processing, it was essential to operate the computer for days and nights. For same reason, a separate branch was established in2031B.S., which was latr named as National computer Centre. National Computer Center was using Second Generation computer Like IBM 1401. In 2038 B.S., a better Fourth Generation computer was imported with the aid of UNDP and UNFA from England in 20 lakhs American dollars. Its name was ICL 2950/10. With the help of ICL2950/10, The census of 2038 was completetd in 1 year 3 months . This computer had 64 terminals. THis computer lis in the musem of NCC(National computer center), Singh Durbar, since it is out dated. For proper handling and operation of this computer, the British Government trained the manpower of National Computer center and awarded the degree like graduate, post graduate or diploma.

In the meantime, students went to India Thailand and USA for computer studies on their own. In 20369 B.S. the micro computers such as Apple, vector or sirus were imported on pesonnel level. New companies such as Computer Consultanc(c), Management Information processing system(MIPS) and Data System International (DSI) were established. Now, There are many companies which deal with computer traing, servicing , maintainance, upgrading, etc.. Students of every field are intersted in computer. One of the main reason is the prospect of getting a better job. Government employed IBM 1401 in agricultural data processing, industarial data processing , inventory of agricultural bank, provident fund and SLC result processing. As the machine became incapalble of handaling data, in due course of time, ICL 2950/10 was brought in use which was more efficient and was ued for data processing in some other corporation such as tele comunication , Electricity Authority, Janakpur cigratte Factory , Heatuda Cement Factory, Tribhuwan University, etc.
In Kathmandu and Patan only , t is estimated that 90% of the computer are centeralised. Besides, in Bhairawa, POkhara , japha nad almost in all part of countery Computers are used for traning purpose and in offices, schools coleges and also in supermarkets. At the same time, Compute science as a subject has been taught at schools , colleges and univesity level in Nepal.

COMPUTER

With the change in time and new discoveries in computer science,human life is no more a static existence. Advancement in information technology , networking and globalization has forced us to remain vary of changes taking place in the world today.
The last few decades of the twenth first century have witnessed the radical changes taking place bothe in our lifestyle and computer technology concomitantly. The change is so rapid that we cannnot use the same software a long time due to the modification in th newer version. Howver, the new version of sftware had basically two distinct advantages :they have simplified menu system and more facilities.
COMPUTER
computr are developed as a result of man's search for a faster way to calculate. Computers are very fast because data and instruction are represented as pulses within electronics circuits and they travel at the speed of light. one day s work on a computer would take a person with a hand calculator,more than 2700 yeas. People who cntributed to make this possible were phhiloshoper, inventors, mathematics, programer, etc... Long before machines existed , people found ways to calculate. They used to count using their fingers or arranged stones in piles or row.They drew lines on the ground , cut notches in sticks or tied knots in stings in order to keep track of the quantities of things. As thier need to calculate increased,people sought tools to help them.
Around fifth century A.D., Hindu philosohers developed a new method of counting from 0 to 9. This system of counting is called the decimal method . THe numbers stated above 0 to 9 are the digits. Digit is a finger or toe , and counting on one's fingers is called the digital operation.The vast majority of computers seen today are electronic digital computers and their names suggest that they carry out their work by performing high speed digital operations on data. The first electronic digital computer were built in the mi 1940s. Their forerunners were a number of digital devices, of which the abacus is one. All these began with counting of pebbles, which of course, was the earliest method.
ABACUS

Abacus is portable device that consist of beads strung on wires or wooden rods. Using an abacus one can rapidly and accuraely add, subtract, multiply, or divide large numbers. No one is sure about exaclty when the frist abacus appeared. Historiians agree though, that this device appeared between 2000 and 5000 years ago and that had its origin in ancient china, egypt and grecce . Abacus is still used in some parts of the world today. Abacus has two parts divided by mid bar. The part above the mid bar is called heaven and each bead has a value equal to 5. The part below the mid bar is called earth and each bead on earth has a value equal to 1.

Microsoft Corporation

Microsoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices. Its headquarter located in Redmond, Washington, USA. Its most profitable products are the Microsoft Windows operating system and the Microsoft Office suite of productivity software.
The company was founded in 1975, to develop and sell basic interpreters for the Altair 8800. Microsoft rose to dominate the home computer operating system market with MS-DOS in the mid-1980s, followed by the Windows line of operating systems. Many of its products have achieved near-ubiquity in the desktop computer market. One commentator notes that Microsoft's original mission was "a computer on every desk and in every home, running Microsoft software.Throughout its history the company has been the target of criticism, including monopolistic business practices and anti-competitive strategies including refusal to deal and tying. The U.S. Department of Justice and the European Commission, among others, have ruled against Microsoft for antitrust violations.

Human Research For Information Technology

Information Technology plays a vital role for development of human research and for their living.All human interaction, including human research, has ethical dimensions. Responsibility for the ethical design, review and conduct of human research is exercised at many levels. While the processes of ethical review are important, individual researchers and the institutions within which they work hold primary responsibility for ensuring that their research is ethically acceptable.There is no doubt that Internet is an effective Digital Channel to improve the target interaction with lower costs for distribution of information and multimedia content, at the same time being a medium that reaches out to a global audience.It is also an ideal channel to manage digital customer data improving the knowledge about your target.FuturLink platforms are focused on improving marketing actions and effectiveness of the sales process over the Internet, for example moving people from the website to the Point of Sale.