Computer Fundamentals Sem1 Essay


1. Information is obtained through processing of data. The storage, retrieval and processing of data become the essential resource for all economic and social exchanges.

Information is a vital resource in development activities of any society. All our economic and social progress depends very significantly in the transfer of commercial, scientific and technical information. People in different situations require information on a subject in different forms and with different emphasis. Data is the recording of any meaningful event in any understandable form.The methods used to collect and store the data, process the data into information and communicate the information all over the world is Information Technology.

This technology is a revolution sweeping across the world. It is interesting to know that 75% of all information generated in the entire history of mankind has been generated in the last 30 years. Data, Instruction and Information.

Many of the events that occur are significant or meaningful to the organisation. When an event is significant or meaningful, we record it.Data is nothing but the facts and figures that record meaningful events occurring in an organisation. Information on the other hand is processed data. Data is the raw materials for producing information.

Information is the basis on which executives take decisions. Through we can conceptually differentiate between data and information there is no strict demarcation between these two. What is data to one person could well be information to another. Data is processed according to requirements and suitable instructions that are given. Data Processing System: Data:Data is raw fact and figure which helps to process to produce the information.

Information: “Information refers to an input of data processing which is organized and meaningful to the person who receives it”. For example, data concerning a sale may indicate the number of the salesman. When a large number of such data elements is organized and analyzed, it may provide important information to a marketing director who is attempting to evaluate his sales force. Also if a production manager is told that, not only the production is behind schedule but also it is 75% of the schedule target is information to him.In general, the planning information requirements of executives can be categorized into three broad categories viz… ? Environmental Information. ? Competitive Information. ? Internal Information. Characteristics of Information: Important characteristics of useful and effective information are as follows: i) Accuracy: Information, if it is to be value should be accurate and should be truly reflects the situation or behaviour of an event as it really is.

Otherwise the user will take the incorrect information as correct and may use it for decision – making with a disastrous result. i) Relevance: It refers to current utility of information in decision making or problem solving. iii) Form Information: Is of value is it is provided to the user in the form it is useful and best understood by him. iv) Timeliness: It means that information should be made available when it is needed for a particular purpose and not before and in any case not after. Delayed information has far less value as a resource. v) Purpose: Information must have purpose at the time it is transmitted to a person or machine, otherwise it is simply data.The basic purpose of information is to inform, evaluate, [persuade or organize other information, create new concepts, identify problems, solve vi) Completeness: Information is considered as complete if it tells its user all what he wishes to know about a particular situation/problem. The more than completeness of information the higher is its value.

vii) Validity: It measures the closeness of the information to the purpose which it purports to serve. viii) Reliability: The information should be reliable and external force relied upon indicated. Q. 2)Ans:Several computing models have been used to provide timely information to managers in an organisation. Currently the information system is organized as a Network (Local Area Network or Wide Area Network) using File/Server technology. In order to support large data access, the Client/Server technology is used.

Local Area Network or LAN is a communication facility that covers a limited geographical area (such as within the same building) and interconnects in an effective manner with different types of computers. The computers are usually within 100 to 300 meters.Wide Area Network or WAN is a wide area communications facility that covers a wider geographical area-ranging from a few kilometers to around the globe and supported by transport media such as terrestrial microwave link, satellite, modems, network control centers etc. File/Server: For sharing data in a LN (Local Area Network), the user stores files on a file server. A file server is a central node that stores data files where all users can access them. The file server in a LAN acts as a central hub for sharing peripherals like printers, print queues, and modems. In a LAN, an application running on orkstation (a PC connected to the LAN) reads and writes files on the file server.

In many cases entire files are transferred across the network on behalf of the operations taking place on LAN PCs. A file server is not involved in processing of an application. It simply stores files for application that run on LAN PCs. For e. g. you might have a personal database manager on your LAN PC. First, you start your personal database manager and then request information in a file on the file server. The file server ends all or part of the data file across the network to your workstation.

As you work with your personal database manager and the database on your workstation, the file server does not take part in the activity at all. When you save the file, you copy the data file back to the file server across the network. Unfortunately, the built-in design of the LAN/File server computing model as prevents it from adequately servicing demanding multi-user, shared-data applications that can be supported easily by mainframes. Two flaws limit a file server system for multi-user applications. Client/Server: The Client/Server system delivers the benefits of the network-computing model along with the stored data access.Any local area network could be considered as client/server system, since the workstations (clients) request services such as data, program files, or printing from server.

A client/server (CIS) has three distinct components, each focusing on a specific job: a data base server, a client application and a network. A server (or “back end”) gives stress on efficiently managing a resource such as a database of information. Its main job is to manage its resource optimally among various clients that concurrently request the server for the same resource. Database servers mainly concentrate on the following tasks: ?Managing a single database of information among many concurrent users. ? Controlling database access and other security requirements. ? Protecting database of information with backup and recovery features. ? Centrally enforcing global data integrity rules across all client applications.

A client application (the ‘front end”) is the part of the system that users apply to interact with data. The client applications in a Client/Server database system focus on the following job: ? Presenting an interface a user can interact with to complete the job. ? Managing presentation logic such as pop up lists on a data entry form. Performing application logic, such as calculating fields in or data entry form. ? Validating data entry. ? Requesting and receiving information from a database server. Internet: Introduction and use: The Internet is “a network of formwork”.

It is a global collection of high-powered computers that re connected to each other with network cables, telephone lines, microwave dishes, satellites etc. Each computer on the Internet stores documents, sound files, video clips, program files, electronic shopping centers, animations, pictures, interactive contents and other things that can be stored and presented electronically.All these resources are available to the computer, which connects to the Internet. Any person who is connected to the Internet in connected to your computer. One can communicate with anyone on the Internet by sending e-mail, posting messages in newsgroups, chatting in various chat areas, and even telephoning and video-conferencing over the Net. A Network of Networks: The Internet is a network of Wide Area Network. In a corporate wide Area Network, each department has a local Area Network that allows sharing of files, database, printer and other peripheral devices.

In a network Data must be safely transferred from one destination to the other.Each destination will have a specific address. For the safe transfer of data the rules namely TCP/IP are implemented in the Network software – Transfer Control Protocol (TCP) and Internet Protocol (IP).

TCP is responsible for breaking up large batch of data into little data packets. IP is responsible for packing the destination address information in these packets. ? E-MAIL: the most popular service on the net is the E-mail. One can use it for anything where paper and telephone world otherwise have been used. ? World Wide Web: this allows the user to jump from one location on the Internet to another.

Using a popular software interface such as Internet Explorer or Netscape, a user could access any document on the net and have access to graphics, text, sound and video. ? Browser: Using a “Browser” (e. g. Netscape, Internet Explorer etc. ) one can access a hyperlinked database of text, pictures, sound and even animation. ? File Transfer Protocol (FTP): Files related to lawyer’s case studies, budget matters, cricket statistics, etc. , just about anything any database you would want to access or any non confidential file that is stored in the net can be retrieved.

All you need is an account name on the host computer and the password to that particular account. ? Veronica: If you want information on jeans, you could use the Very Easy Rodent Oriented Netwide index to Computer Archives or simply VERONICA. ? Chat: A form of real-time electronic communications where participants type what they want to say, and it is repeated on the screens of all other participants in the same chat. Internet Relay Chat or IRC is an Internet protocol for chat, and there are many other chat systems in services like Delphi.Other commonly used chat systems are iChat and ICQ.

Q. 3) Ans:The numbers are the pre-defined value symbols, which has specific meaning. The knowledge of number systems is most important and essential because the design and organization of computer/electronic components dependent upon the number systems.

The electronic components are worked on signals that re represented as ‘ON’/’OFF’ [pulse] codes. The principles of data transmission is representing ‘ON’ & ‘OFF’ signals of electricity, where they represent the ‘presence’ or ‘absence’ of an electrical pulse.These two alternatives, of one or the other of two states in all the two – state device, are denoted in the “BINARY CODES” as ‘0’ and ‘1’, where ‘0’ marks the state of absence and ‘1’ marks the state of presence. All such devices inclusive of the computer, are called “two-state devoices”. Example: Code as Binary ‘0’Code as Binary ‘1’ ? ?? ?? ?? ? Electrical witch in OFF position Electrical switch in ON position Number System are Basically Classified into two Types: 1. Non-Positional Number Systems. 2. Positional Number Systems.

1. Non-Positional Number Systems: This system is used for small quantity counts to represent the objects.With the help of fingers, stones, pebbles and sticks which indicates the values. The total object values of all the individual elements represent as sum, this approach is call Ed the “Non-positional number system”. The roman numbers system is a best example of the Non-positional number system.

In this system each symbol represent the definite values irrespective of the position in which they appear, but this method of number system is not suitable to perform the arithmetic equations. 2. Positional Number Systems This system is used for huge quantity counts to represent the value, using certain well-defined symbols that are called “digits”.These digits are representing values with its position in which they appear. The digit value is dependent on following main three factors: 1. The face value of the digit [i. e. the Digit itself].

2. The base of the number system. 3. The Position of the digit in the number. Number Systems: The various number systems discussed are: 1. DECIMAL number system: It has a base 10. [It utilizes the symbols of the numbers from 0 to 9]. 2.

BINARY number system: It has a base 2. [It utilizes the two symbols ‘0’ and ‘1’]. 3.

OCTAL Number system: It has a base 8. [It utilizes the symbols of the numbers from ‘0’ to ‘7’]. . HEXADECIMAL Number system: It has a base 16. [It utilizes the symbols of ‘0’ to ‘9’ and A to F].

(234)10 8 234 8 29-2 (352)8 3-5 Q. 4 Ans:The term ”Computer” could literally be used to identify any device that calculates. Initially, the Computer was designated as a toll to manipulation numbers and solves arithmetic problems, this original use is understandable, since most of the early designers and users were mathematicians, scientists, and engineers. However, people began to realize that the Computer could process alphabets as well as numbers and special characters.Therefore, the literal interpretation of the word “Computer” makes the word some things of a misnomer. Since the computer does more than just carry out addition, subtraction, multiplication, and division. Indeed, the computer can read input data, stores, retrieve data and process the data to stores, retrieve data and process the data to than just computing, the Computer is sometimes more descriptively called an “Electronic data processing Device”.

Define Computer: “Computer is an Electronic device which stores, reads and processes the Data or Information to produce the meaningful results, /outputs”.In the case of Computers, two kinds of inputs are required The basic raw Data and A set of instructions containing the methodology to process the data that are called as Program. Process: It involves the series of calculations or series of changes to be done on information. Characteristics of a Computer: The major characteristics that make the computer such a powerful machine can be enumerated as speed, storage, accuracy, ability to operate automatically, diligence, scientific approach and versatility. Speed:The speed however in incredibly faster than what man can possibly record or calculate normally.

The speed of computer is usually given in terms of the following time units for the access time. TIME : Millisecond[1ms] -A thousand of a second or 10-3. Micro seconds [1µs]-A millionth of a second or 10-6. Nano seconds [1ns]-A million millionth of a second or 10-9.

Pico second [1ps]-A million millionth of a second or 10-12. The speed of computers is also measured in terms of instructions per second. There are two such measures. KIPS – Kilo instructions Per Second. MIPS – Million Instructions Per Second.Storage: One of man’s failings is perhaps his inability to remember and ‘store’ large volumes of information in his brain.

The computer is capable of overriding this deficiency as it can store. In computer the terminology in regard to storage capacity applies to both ‘primary’ and ‘secondary’ storages. It is normally measured in terms of nibble, Byte, Kilobyte (1KB) Mega Byte (MB), Giga Byte (GB) and Tera Byte (TB). So in computer’s memory large volumes of data to be maintained more prominently on secondary media.

Example: Floppy disks, magnetic disks & tapes etc. Accuracy and Reliability:In spite of high speed, the computers are quire accurate and reliable in its calculations. The accuracy of operation of computer is always 100%. Computer is only a machine and does not make errors on its own. It is thus reliable. Automatic: The computer is quite capable of functioning automatically, once the process has been initiated. It does not require a prompt from an operator at each stage of the process.

Diligence/Endurance: Man suffers from physical and mental fatigue, lack of concentration and laziness which do not permit him to carry on his task at the same level of speed and accuracy through the entire day.The computer, on the other hand is capable of operating at exactly the same level of speed and accuracy even if it has to carry out the most voluminous and complex operation for a long period of time. Scientific Approach: The entire approach to solving problems is highly scientific, objective and sequentially carried out, leaving no room for emotional and subjective evaluations made by man, which are sources of potential errors and unjustified results.

Versatility: The wide use of computers in so many areas such as scientific, commercial applications.Educational industrial areas in day-to-day life there is an ample evidence of its versatility. Criteria for Using Computers: In present world, computer is very useful in almost all walks of life. Some of the major criteria for using computers are listed as follows. i) To make available information quickly: this is an (important) vital criteria for using computer for processing raw data and converting it into meaningful information.

As an electronic device works at a high speed, therefore it makes available the desired information to user quickly and promptly. i) To provide highly accurate and reliable information: Data processed by utilizing the services of properly programmed computers is highly accurate, reliable and dependable. It is so because computers perform their task as per the given program/instruction. iii) To reduce the paper work: The use of computers for data processing has helped the management of Business Organisation to cope with the increasing problem of paper handling by not only speeding up the process, but also by eliminating some of the paper needs through, the storage of data, in elaborately constructed data bases and file where they can retrieved when needed. v) To identify of problems areas: Computer facilitates the identification of business problem by carrying out the analysis of available data.

It also helps the management to corrective action over the business problem. v) To prepare reports: Computers facilitates the preparation of various type of organization required reports such as financial and non financial reports, inventory reports for decision making and control, in short span of time. There are many useful ways in which computers are classified: 1. By the types of data they are capable of manipulating (Digital or Analog). 2. As a mixture of data handling type i. are called Hybrid computers.

3. Scientific and Commercial Computers. 4. By the purpose for which they were designed (special purpose or general purpose computers). 5. On the basis of Price, Size and Capabilities following computers are classified – Main Frame. – Mini Computers. – Micro Computers.

Micro Computers: Slow, cheap, significant computing power, use of INTEL chips. Single processor system which can support the simple tasks like WP, ESS, DBMS etc. Example: PS 386, 486, Pentium (P-1, II, III, IV). Mini Computers: Relatively faster and low cost compared to mainframes, higher than PCs.

Designed for real time dedicated multi user applications. IBM-17, HP-3000, DECPDP-11. Mainframes: Faster than Mini computers, have larger memory used in CPU intensive or I/O intensive Jobs, like Example: In scientific and business application. To process high volumes of data in large business applications.

Example: IBM-370 & IBM-S/390, DEC VAX-8800, CPC-7600, UNIVAC-1110. Super Computers: Large in size and large memory compared to all other computers ideal for high-end computing applications involving large volumes of data and intensive computing use non-INTEL chips.These Computer are designed for ultra high performance tasks such as Encryption cracking, creation of animation and for designing all knowledge based systems. Example CDC Cyber family, CRAY X-mp/26, IBM’s Deep Blue. Analog Computers: These computers represents numbers by as physical quantity that is they assign numeric values by physically measuring some actual property, such as the length of an angle created by two lines, or the amount of voltage passing through a point in an electric circuit. Analog computers derive all their data forms in some form of measurement. Digital Computer:In these computers represents data as numbers or separate units, a digital computer operates directly decimal digits that represent either discrete data or symbols.

It takes input and gives output in the form of numbers, letters and special characters. Digital computers are generally used for business and scientific data processing and also had a unique ability, and that is storing large quantities of data. Hybrid computers: Hybrid computers combine the most desirable features of both analog and digital computers. They have the speed of analog computers and the accuracy of digital computers.They usually used the special problems in which input data derived from measurements is converted into digits and processed by computers.

For example, in hospital intensive care units, analog devices may measure a patient’s heart function, temperature and other vital signs. These measurements may then be converted into numbers and supplied to a digital device, which may send immediate signals to a doctors/nurses station if the abnormal readings are detected. Q. 5) Ans:Computer Memory classified into two types: 1) Primary Memory.

2) Secondary Memory. 1) Primary Memory: It may be called as MAIN MEMORY or Internal Memory.It built with in the computer that stores the unprocessed and processed data as well as the program instruction. It is immediate Access Memory. It is of a limited in capacity and temporary in nature. The information resides in the secondary memory, are needed by CPU for current execution is transferred from the Secondary Memory to the Main Memory.

The standard base memory is 640K or KB. It may enhance up to 1MB, 2MB, 8MB, 16MB, 32MB, 64MB, 128MB and 256MB depending on need of the user. Example: RAM – Random Access Memory.

ROM – Read Only Memory. – PROM-Programmable Red Only Memory. – EPROM-Erasable Programmable Read Only Memory. EEPROM-Electronic Erasable Programmable Read Only Memory.

2) Secondary Memory: The primary memory being within the computer has limited storage capacity and its temporary in nature, to overcome thee limitations, it is necessary to retain the data and program permanently for the future use, which could be huge storage capacity and present outside the CPU, these are may called as “Backing Storage Devices” or “Secondary Memory” or “External Storage Devices”. Secondary memory storage capacity is huge and permanent in nature, instructions can be updated any time. Example: Magnetic media – [Magnetic Disk/Tape/Drum], – Magnetic Tape.

Magnetic Drum. – Magnetic Disk (Floppy Disk, Hard Disk etc. ). – CD–ROMS. Functions of Primary Memory: 1) To hold the Operating system Instructions when Boot the Computer [Turned on the System]. 2) It holds the copy of the programming instructions and data are input from the Keyboard through user temporarily, that are currently being executed.

3) It store the result temporarily, which is generated after processing until it is transferred to corresponding output device. RAM: RAM is identical to core memory in function and is a read/write memory. Data can be stored in RAM by addressing one RAM cell.The data and instructions fed in via the input device are stored in the RAM so it may be called as user’s memory.

RAM instructions are temporary in nature and are presents only for the time that the program is being used. RAM instructions can be updated. There are Two (2) vital types of RAM 1. Static RAM (SRAM): It retains stored information till computer is under working. 2.

Dynamic RAM (DRAM): It loses its stored information in a very short span of time even though computer is under working. ROM: It is permanent memory storage, as the name suggests, is that part of the memory which is only ‘Read’ by the computer.This memory is non-volatile has fixed instructions on it, i.

e instructions are related to the operating system of computer. These instructions are written by machine manufacturers and these instructions cannot be updated by the user. When you turn on the system, the ROM instructions are instantly activated to get activated of all Input/Output Devices. |Sr. No.

|RAM |ROM | |1 |RAM instructions are temporary in nature. |ROM instructions are permanent in nature. |2 |Instructions can be Read and Write from the memory. |Instructions can be only Read from the memory. | |3 |Instruction can be updated (add, modify, delete) by user. |Instructions can not be updated by user.

| |4 |RAM is volatile memory |ROM is non-volatile memory. | PROM: Programmable Read Only Memory: This memory is non-volatile type. Instructions can be written once by the programmer and then can be subsequently read. PROM chips are custom made for the user by the manufacturer. EPROM:Erasable Programmable Read Only Memory: This memory is non-volatile type. In this type of memory, instructions can be rewritten by the programmer using special techniques.

These chips were developed as an improvement over PROM chips. With the help of special device that uses ultraviolet light, the data/instructions on an EPROM chip can be erased, and new data/instructions can be recorded in its place. To change the instructions on an EPROM you have to remove the chip from machine and then put back when changes have been made. EEPROM: Electronic Erasable Programmable Read Only Memory:It is an advance addition to the ROM family of chips, to avoid the inconvenience of changing the instructions by taking the chip outside the machine. Instead, changes can be made electrically under software control. These chips are being used in Point-of-Sale (POS) terminals to record price related data for products.

So, the prices recorded on them can be easily updated as needed. The main disadvantages of EEPROM chips are more costly than regular ROM chips. Difference between Primary Memory and Secondary Memory: 1) Primary Memory: a) Primary memory is much faster and also it is more cost effective. ) Primary memory is used by the system to perform operations while programs are running. c) Primary memory is directly accessible to the CPU. d) In Primary memory the storage capacity is limited.

e) It has a volatile memory. f) These devices are temporary. g) These devices are expensive. 2) Secondary Memory: a) Secondary memory is much slower and also less costly. b) Secondary storage (or external memory) is not directly accessible by the CPU. c) Secondary memory is used for permanent storage of information. d) In Secondary memory the storage capacity is larger.

e) It is a non-volatile memory. ) These devices are permanent. g) These are cheaper. Q.

6) Ans:The Windows XP approach to security is discretionary. That is, each securable system resource-each file or printer, has an Owner, who has discretion over who can and cannot access the resource. Usually, a resource is owned by the user who created it. If user creates a file, for example, then he is the file’s owner under ordinary circumstances.

To determine which users have access to a resource, Windows assigns a security ID (SID) to each user account. This SID is unique number, follows the user around whenever log on in Windows.When he/she log on, the operating system first validates his user name or password.

Then it creates a security access token. It concludes user name and SID, plus information about any security groups to which the account belongs. Any program he/she start, gets a copy of security access token.

Whenever he attempt to walk through a controlled “door” in, or any time a program attempts to do that on his behalf, the operating system examines his security access token and decides whether to let him pass. If access is permitted, he will notice nothing.If access is denied, he will see an unavailable menu or dialog box control or, in some cases a refusal message with beep sound. Permissions and Rights: Windows distinguishes two (2) types of access privileges: permissions and rights. A permission is the ability to access a particular object in some defined manner-for example, to write to an NTFS file or to modify a printer queue. A right is the ability to perform a particular system wide action, such as logging on or resetting the clock.

User Accounts: The backbone of Windows XP security is the ability to uniquely each user.Computer administrator creates a user account for each user. The user account is identified by a user name and (optionally) a password, which the user provides when logging on to the system. Windows then controls, monitors, and restricts access to system resources based on the permissions and rights associated with each user account by the resource owners and the system administrator. ? Administrator Account: Every computer running Windows XP has a special account named Administrator. This account has full rights over the entire computer. It can create other user accounts and is generally responsible for managing the computer.Many system features and rights are off limits to accounts other than Administrator (or another account that belongs to the Administrators group).

? Guest Account: The Guest account resides at the other end of the privilege spectrum. It is designed to allow an infrequent or temporary user such as a visitor to log on to the system without providing a password and use the system in a restricted manner. By default, the Guest account is disabled on a clean install of Windows XP; no one can use an account that’s disabled.

The Guest account is also used for access to shared network resources on the computer when Simple File Sharing is enabled.Account Type: Account Type is a simplified way of describing membership in a security group, a collection of user accounts. Windows XP classifies each user account as one of four account types: ? Computer Administrator: Members of the Administrator group are classified as computer administrator accounts. The Administrators group, which by default includes the Administrator account and all accounts you create during Windows XP setup, has more control over the system than any other group. Computer administrators can – Create, change, and delete user accounts and groups. – Install programs. – Share folders. Set permissions.

– Access all files. – Take ownership of files. – Grant rights to other user accounts and to themselves. – Install or remove hardware devices. – Log on in Safe Mode. Limited: Members of the Users group are classified as limited accounts.

By default, limited accounts can – Change the password, picture and associated . NET Passport for their own user account. – Use programs that have been installed on the computer. – View permissions (if Simple File Sharing is disabled). – Create, change, and delete files in their document folders. – View files in shared document folders.

Guest: Members of the Guests group are shown as guest accounts. Guest accounts have privileges similar to limited accounts. A user logged on with the Guest account (but not any other account that is a member of the Guests group) cannot create a password for the account.

Unknown: The account type for a user account that is not a member of the Administrators, Users, or Guests group is shown as Unknown. This Unknown account type is automatically created if the computer is upgraded from an earlier version of Windows or if used, the Local Users And Groups console or the Net Localgroup command to manage group membership.