Computer is an electronic processing machine, which gets the input, process on it at very fast speed and then produced the output and also stores a lot of information.
There are two way of classifying computer
Classification on the basis of their working principal.
o Analog computer
o Digital computer
o Hybrid computer
Classification of the basis of their configuration, size and performance.
o Mini computer
o Micro computer
o Main frame computer
Classification of the basis of their Working principal
Analog computer: -
Analog computer represents the data by measurable quantities, as voltages or frequency rather than by expressing the data as numbers. Its measures the continuous change in some physical quantity. e.g Speedo meter of car measure speed in term of KM/H or M/H, the changes of temperature is measured by thermometer in degree. These computers are ideal in situation when data can be accepted directly from the measuring instruction without having the convert it into number of codes. Analog systems are used to control processes such as oil refinery where flow of temperature measurement are important.
Digital computer: -
These types of computers process the data in digital form which is based on the presence or the absence of an electrical charge. These types of computers are used for scientific calculation and business oriented job.
Hybrid computer: -
A hybrid computer is combination of both analog and digital computer. In these computers some portion of processing is done on analog data and other is on digital data. Hybrid computers combine the characteristics of both analog and digital computer. It provides greater accuracy than can be attend with digital computer, grater control and speed then is possible with analogs. It can accept input data in both analog and digital form. It is used for air defense system, different laboratory equipments for medicine etc.
Classification of the basis of their configuration, size and performance
Main Frame: -
Main Frame computer are Large in size, Large in memory, more powerful and more expensive. These types of computer are designed for the computerization for the data of huge business, university, bank, and scientific laboratories national and international market. Mainframe computer place in a large room because it includes many types of peripheral equipment attach with it.
Mini computer
Mini computer are small in size as compare to main frame computer. These types of computer designed for the computerization of the data of scientific research and data collection, industrial process control and small business application. These types of computer are operated by more than one user at a time. Minicomputer usually fills small rooms because it also includes many types of peripherals equipments attach to it.
Micro computer: -
Micro computer are also called PC, smallest in size, very small in memory, least expensive. These types of computer are designed for personal use. These are used for small-scale domestic and business application. Microcomputers are easily accommodated on a table and thus have the names desktop computer. These are highly flexible. The basic of the microcomputer are microprocessor, a silicon chip containing the necessary circuitry to perform arithmetic logical operation and the control I/O operation.
There are the following main features of computer
Speed: -
The speed of electronic computer is very fast because the signal can pass at the speed of electricity, which is same as that of light. Thus million of calculation can be done in a second.
Storage and retrieve of information: -
Computer can store large amount of data, instruction and information on its internal memory and secondary storage device and the same can be easily access and retrieved.
Consistency
Computer can’t become bored or tried or loss concentration when performing high repetitive jobs unlike human beings. Every time same work is done by equal diligence by the computer
Automatic operation: -
One data and program have been fed into the computer. Operation of computer is automatic
Accuracy: -
Computer work very accurately and result are always same as per design. Accordingly software need to be designed properly check and control are necessary I program and data
Flexibility: -
General-purpose computer may be used for verity of purposes depending on the program fed into the computer.
Computer is an electronic processing machine which get the input , process on it very fast speed and then give the output after processing. Computer also stores our information and we can access this information any time when we need. A computer capable of performing computation and making logical decision at speeds thousands of seven million of time faster than human being.
The main components of computer are :
1. Input Unit
2. Output unit
3. Central Processing Unit (CPU)
4. Memory Unit
The basic unit, which provides communication between the user and the computer, is the input unit. This unit describes a device, used to transfer information into a computing system. It performs following three functions.
It accepts data from user.
Converts that data into electrical signals, which can be later, used in arithmetical calculations.
Coded data is then moved to the system for processing.
The data can be fed into a computer by using different types of input devices. The commonly used input devices are Keyboard, MOUSE etc.
CPU is short form central processing unit. The central processing unit is responsible for performing all of the mathematical and logical calculations that are required for a computer to function properly means that work of CPU is Data Processing. The function of CPU is consisting on four steps to perform processing function.
The first step in this cycle is to fetch a instruction from a software program's memory. Once the CPU fetches the instruction, its second step is to decode the instruction. By decoding the instruction, the CPU is able to organize the information from the instruction in a manner that allows the CPU to complete the next step, which is executing.
Memory unit responsible for storing the information permanently and temporary during the processing. Computer memory is mainly divided in to two types.
Primary Memory
The output unit gives the output of our input after processing. This is final step, which presents the results of the machine operations in printed or other visual form. It is a device that receives results from a CPU. It can be a communicating link between a computer and people. It. is used to transfer information out of a computing system.
MEMORY
Computer memory is an electronic circuit that holds data and program instructions until they processed. Memory devices are responsible for storing the information permanently and temporary during the processing.
Computer memory is mainly divided in to two types.
· Primary Memory
· Secondary Memory
Primary memory which is also called main memory stores the information in form of binary coded data. Primary memory holds the input data before processing and the information after the processing and also provides the permanents storage as requested. It is also called Internal Memory.
There are following three type of main memory
RAM is an abbreviation for Random Access Memory. It usually refers to "temporary" memory, as when the system is shut down, the memory is lost. This is why the memory is referred to as being "random," as any piece of information can be circulated through the memory regardless of its location and its relation to any other information within the RAM. The ram store the data before and after the processing.
CMOS is short from Complementary Metal Oxide Semiconductor. This memory hold the data, but requires very little power to retain its contents a CMOS chip is usually powered by battery, CMOS stores data about computer configuration. All configuration such as how many floppy drives are there in computer or the size of hard disk etc, all this data retain in CMOS memory.
ROM is short from Read only memory. This memory consists on electronic chips that contain instructions to help a computer prepare for processing tasks. The instructions in ROM are written by the time of manufacturing and permanently store on this chip and you cannot change them. When computer is turn on the first of all the instruction is executed are ROM instruction. ROM contains a small set of instructions to tell the computer how to access hard drive and load operating system.
PROM is short for programmable read only memory. These types of memory also consist on an electronic memory chip on which data can be written only once. Once a program has been written onto a PROM it remains there forever. The difference between ROM and PROM is that a PROM is manufacturing as blank memory, whereas a ROM is programmed during the manufacturing process. To write data onto a PROM chip, you need a special device called a PROM programmer or a PROM burner.
An EPROM is short from erasable programmable read only memory. This is a special type of PROM that can be erased by exposing it to ultraviolet light. Once it is spread, it can be programmed. EPROM is a similar to a PROM, but is requires only electricity erased.
A computer contains a master clock that produces pulses to establish the timing for all system operations. The clock rate set by the master clock determines the speed at which the microprocessor can execute an instruction. This controls the number of instructions the microprocessor can complete within a specific amount of time. The speed at which a microprocessor completes an instruction execution cycle is measured in Megahertz (MHz) or million of cycles per second. The microprocessor is the original IBM PC executed 4.77 million instructions per second.
Word Size, Refers to the number of bits the microprocessor can manipulate at one time. A microprocessor with an 8-bit word size, called an 8-bit microprocessor, can manipulate 8-bits at. a time. A 16-bit, microprocessor, can manipulate 16-bits at a time, a 32-bit microprocessor, can manipulate 32-bits at a time and so on. A microprocessor with a large word size, can processor more data in each instruction cycle and generally operates more quickly than a microprocessor with a small word size.
A math coprocessor contains special circuitry to perform complex arithmetic operations much faster than the ALU. A math coprocessor enhances system performance. Certain activities such as calculating large worksheets or generating statistics for large databases are finished faster if you have a math coprocessor. If your computer does not have a math coprocessor, you can add one if main board of your computer has an empty-coprocessor socket.
Cache memory is also temporary memory which is built in with microprocessor. The read and write speed of this memory is same as the speed of microprocessor. Cache memory is major factor that affects the performance of a microprocessor. A high-speed microprocessor can process data so quickly that it often waits for data to be delivered from RAM, and this slows processor. Cache memory is special high-speed memory that gives the microprocessor more fast access to data.
Flash memory is a memory, which retains the data even after power is off.
Flash memory is a form of EAPROM (Electrically Alterable Programmable Read-Only Memory).
Each bit of data in a flash memory device is stored in a transistor called a floating gate. The floating gate can only be accessed though another transistor, the control gate.
Popular flash memory devices include:
· Sony's Memory Stick
· Compact Flash
· SDCard
· MultiMediaCard (MMC)
A video display adapter contains the circuit to support the display of text and graphics on the monitor. It is sometimes built into the main board, but more often it is a graphics card high-speed video card can move data between the microprocessor and the video card as faster as the microprocessor can process it.
A parallel port provides a connection for transmitting data eight bits at a time over a cable with eight, separate data lines. The parallel ports are relatively fast. These are usually used to send data to the printer. To connect the printer to the computer, both the computer and the printer must have a parallel port.
The parallel port is either built into the main board or mounted on an expansion card.
A serial port provides a connection for transmitting data one bit. at a time. A serial port connects the computer to a device like modem, which requires two-way data transmission, or to a device like mouse, which requires only one-way data transmission.
To connect a peripheral device to the computer through a serial port, both the devices must have, a serial port. The serial port is either built into the main board or mounted on an expansion card.
Computer software are collection of programs where program are instruction to given to computer to perform any specific task. There are two type of software system software which are design to control the hardware and manage the computer system for example operation system and drivers on the other side Application software are those program which perform some specific task such that word processor , multimedia software etc.
1. System software:
System software are those programs which have some instructions which control the Hardware and also other software such that applications in computer. We can say that system software are interface between hardware and user applications. The function of System software are performs the responsibility of overall supervision of input, processing and output of data. It keeps track of all the peripherals equipment attached with the computer, and monitors their activities. System software are divided into following categories:
Operating Systems: -
The operating system provide an interface in which user can perform basic function on computer such that I/O function. The OS create a link between user and computer and manage all the application and hardware resources.
Device Drivers: -
When you purchase a new peripheral hardware device, such as a CD-ROM drive, a mouse or a printer, you need to install software that tells the computer how to use the device. This type of system software is called Device Driver.
Utility Programs:
Utility program are those program which are designed to help analyze, configure, optimize or maintain a computer. For example backup, data recovery, file de fragmentation, disk repair, and virus protection.
Translator:
Translator are also system program that converts source program into object program. When programmer write the instruction in any computer language then Translators convert these instructions in machine code , because computer can only understand machine language.
2. Application Software:
Application software some time also called application package are developed for specific purpose to get the required output. These types of software developed by experts in high/low level languages for end user how use this software. The user can easily learn to operate these software after getting some initial training. There are many application software are available in the market which are used for different purpose. For example word processor for writing and printing the document (e.g MS word Lotus 123), DBMS for creating and managing Database (e.g MS Access , SQL , fox prow), Graphics software (e.g Adobe , Image composer), Multimedia software for playing videos (e.g Media player) and games (e.g Prince, Dave).
Computer is an electronic machine when we give some instruction to computer (when we write any program ) then we must have some language form which we communicate with computer these language are called computer language. For this purpose different languages are developed for performing different- types of work. Languages are divided into two categories.
A. Low Level Language
B. High Level Language
A) Low Level Language: -
The Low-level languages are primary language of computer machine codes. Computer cannot understand instructions given in English. It can only understand and execute instructions given in the form of machine language i.e the language of 0 and 1. There are two types of low-level language.
Machine Language: It is the lowest and most elementary level of programming language and was the first type of programming language to be developed Machine language is basically the only language which computer can understand Machine language is represented inside the computer by a string of binary digits 0, 1. the symbol 0 stands for the absence of an electric- pulse and 1 for the presence of an electric pulse. Since a computer is capable of recognizing electric signals, therefore it understands machine language.
Assembly Languages: It was developed to overcome some of the many problems of machine language. This is also a low level language but it is very important. This language is also very difficult and needs a lot of practice to master it. This language mainly helps in compiler orientation. The instructions of the Assembly language will also be converted to machine codes by language translator to be executed by the computer.
B) High Level Language:
This type of language easy to understand for the human. The High-level language is just like English language and the purpose of developing high-level languages is to enable people to write programs easily. When we write a program in any high level language then first its transfer in to machine code for this purpose a special software are used which translate these instruction in machine code called translator are used. High level languages are basically symbolic: languages that use English words and mathematical symbols rather than codes. For example Visual BAsic , C language , C++ ect.
Word processors are application programs used for creating, editing, printing and saving documents. By using a word processor it is possible to prepare reports, announcements, journals, books, etc.
The great advantage of word processing over using a typewriter is that you can make changes without retyping the entire document. If you make a typing mistake, you simply back up the cursor and correct your mistake. If you want to delete a paragraph, you simply remove it, without leaving a trace. It is equally easy to insert a word, sentence, or paragraph in the middle of a document. Word processors also make it easy to move sections of text from one place to another within a document, or between documents. When you have made all the changes you want, you can send the file to a printer to get a hardcopy.
Some of more important features of word processors are:
Creating Documents:
We can create new document when we need and then save it and when we need we can also reopen this document.
Editing Documents:
Editing means changing the contents of pre written document. Some features of editing are insert, delete, undelete, find & replace, cut/copy & paste, spelling check, grammar check& thesaurus.
Formatting Documents:
Formatting means make some changes in the appearance of document. There are many formatting features are available in word processor. E.g. Changing the fonts, bold, italic, underline, changing font colors, drop cap, columns, page number, header & footer, border & shading are some most common formatting features of word processor.
Printing Documents:
Printing means get the hardcopy of the document. We can print our document in word processing software. We can also print several copy in short time when we need with the help of word processing software.
Saving Documents:
We can save our document for future use and then open when we need it. With this option we can store our document in computer. In word processor we can save the several copy of one document with different name.
Delete text:
We can also delete the unwanted text from our document without any problem.
Cut and paste:
This option allows you to remove (cut) a section of text from one place in a document and insert (paste) it somewhere else.
Copy and paste:
This option allows you to create duplicate text on many locations. This function save our time which is consume in same text writing again and again.
Page size and margins:
Allows you to define various page sizes and margins, and the word processor will automatically readjust the text so that it fits.
Search and replace:
Allows you to direct the word processor to search for a particular word or phrase. You can also direct the word processor to replace one group of characters with another everywhere that the first group appears.
Graphics:
We can also insert the diffirent illustrations and graphs into our document where we need. Some word processors let you create the illustrations within the word processor; others let you insert an illustration produced by a different program.
Headers, footers, and page numbering:
We can also insert the Header and Footer which is a group of text appear on each page automatically on the Head and footer part of the page.
We can also insert the page number. We insert the page number on one page its automatically appear on each page.
Merges:
This feature allows you to merge text from one file into another file. This is particularly useful for generating many files that have the same format but different data.
Spell checker:
With this feature we can correct our wrong spelling and garmier mistake.
Tables of contents and indexes:
This option allows you to automatically create a table of contents and index based on special codes that you insert in the document.
Spreadsheet also called worksheet is a kind of computer programs that let you organize and analysis and store the data in tabular form.
Spreadsheet application is the combination of row and column called Cell, each value in spread sheet sits in a cell.
Spreadsheet software program have a unique ability to calculate values using mathematical formulas and the data in cells.
There are a number of spreadsheet applications on the market, Lotus 1-2-3 and Excel being among the most famous.
MS EXCEL is a Microsoft spreadsheet application. Spreadsheets store the data in rows and column and you can manipulate this data. MS Excel provides range of functions covering a variety of mathematical, statistical, financial and other calculations.
Apple Numbers is a spreadsheet application developed by Apple Inc. as part of the iWork productivity suite alongside Keynote and Pages. Numbers 1.0 was announced on August 7, 2007 and runs on Mac OS X v10.4 "Tiger" and Mac OS X v10.5 "Leopard" only.
Numbers 2.0 was announced on January 6, 2009. It introduced MathType and EndNote features.
Numbers' main competitor is Microsoft Excel. At its introductory demonstration, Steve Jobs pitched a more usable interface understandable to lay-people and offering better control over the appearance and presentation of tables of data.
A "Layout of Lists" metaphor, where spreadsheets are arranged on a canvas and can be positioned and sized independently there along with charts and graphics. This can make different tables on the same sheet easier to style and delineate to users.
It also eases presentation-centric work.
Highly table-centric workflow, where lists are easy to structure with headers and summaries.
Checkbox, slider, and pull down list cells.
Drag and drop of functions from a sidebar into cells.
A Print Preview that allows all editing functions while previewing, as well as realtime scaling and moving of tables to arrange them freely on the page(s).
Open Office Calc is the spreadsheet application which is a part of the OpenOffice software package. Calc is similar to Microsoft Excel, with almost the same abilities.
It is available in many languages and runs on Linux, Mac, Windows, Solaris, and other operating systems. You can get it from the OpenOffice.org website.
It is distributed as free software and written using its own GUI toolkit. It supports the ISO/IEC standard Open Document Format (ODF) for data interchange as its default file format, as well as Microsoft Office formats among others.
Features of Open office calc
· Additional bundled fonts (especially East Asian language fonts).
· Adabas D database. (Note that the OpenOffice database module is not Adabas)
· Additional document templates.
· Clip art.
· Sorting functionality for Asian versions.
· Additional file filters.
· Migration assessment tool (Enterprise Edition).
· Macro migration tool (Enterprise Edition).
· Configuration management tool (Enterprise Edition).
Gnumeric
Gnumeric is a free spreadsheet program that is part of the GNOME desktop and has Windows installers available. It is intended to be a free replacement for proprietary spreadsheet programs such as Microsoft Excel, which it broadly and openly emulates. Gnumeric was created and developed by Miguel de Icaza, and the current maintainer is Jody Goldberg.
Gnumeric has the ability to import and export data in several file formats, including CSV, Microsoft Excel, HTML, LaTeX, Lotus 1-2-3, OpenDocument and Quattro Pro; its native format is the Gnumeric file format
Following are the most important and notable advantages of spreadsheet application.
Entering Data: -
A spreadsheet allows you to enter text, numerical values and formulas into an electronic worksheet. The worksheet's rows and columns can contain numerical data or labels that identify information. Every row is automatically numbered and every column has an alphabetical identifier. The intersection of a row and column creates a cell. Every cell's name or placeholder is unique.
The majority of popular spreadsheet programs have more than 200 columns and thousands of rows. This makes them ideal for storing and reporting large amounts of numerical data
Editing: -
We can edit our data in worksheet. Editing refer to alter the pre written contents. Most spreadsheets also have an undo command that allows you to remove one or more entries that you no longer want. Since spreadsheets are electronic, you can copy and paste data to avoid repeatedly typing the same values. With spreadsheets, it simple to save your work, update data as it changes and compare estimates or forecasts to actual data.
Calculations: -
A spreadsheet provides different ways to calculate our values. We can use function which automatically perform the different calculation for example sums the values, calculate the average etc. When we change any value in cell then excel automatically upgrade our calculation. We can also define our own formulas according to our needs.
Data Analysis
A spreadsheet is a useful tool for sorting and analyzing data. For example sorting, filtering the data, creating pivot table etc.
Charts: -
A chart is a graphical representation of data. In spread sheet application we can make charts from our simple data. There are verity of charts available for example ine graphs, bar graphs, pie graphs, linestep graphs, scatter graphs.
Formatting:
Formatting means make some changes in the appearance of our tables and other contents. Spread sheet provide pre define formatting of tables and also we can customize our table. We also perform conditional formatting.
Database is a collection of inter related information which reduced the redundancy and shareable by more then one user at the same time.
Database software which is also called DBMS (data base management system) is software in which we create and manipulate the database.
Some features of database software are:
Data in database is reliable and accessible by many users at the same time.
Reduced data redundancy, so that reduced the chance of mismatching
Reduced updating errors and increased consistency
Greater data integrity and independence from applications programs
Improved data access to users through use of host and query languages
Improved data security
Reduced data entry, storage, and retrieval costs
Facilitated development of new applications program
CAD means computer-aided design. CAD software is used by architects, engineers, draft man, artists, and others to create precision drawings or technical illustrations. CAD software can be used to create two-dimensional 2-D drawings and also three-dimensional 3-D drawings. For example AutoCAD, Design Cad 3D, Adobe Illustrator etc.
Computer-Aided Manufacturing (CAM)
CAM means computer aided manufacturing. When we use the computers software to control and management of manufacturing processes then this process of manufacturing is called CAM. Such as automatically coordinated operations of conveyor systems, cutting and forming machines, and riveting and welding machines.
Uses Of Computers
Today's computer is used in all the filed of life and its play very important role in development. With the help of computer all the difficult task become easy and time saving with the help of computer. Following are the some very common use's of computer.
Word Processing software is an especially gift for those people who work in office. Word Processing application automatically corrects spelling and grammar and mistakes. If the content of a document repeats you don’t have to type it each time just copy the contents and paste. You can printout documents and make several copies in very short time. It is easier to read a word-processed document than a handwritten one. You can add images to your document.
Internet and sharing information:
You can share your document and other work with different people on the network. On the internet you can browse through much more information than you could do in a library. That is because computers can store enormous amounts of information. You also have very fast and convenient access to information. Through E-Mail you can communicate with a person sitting thousands of miles away in seconds. There is chat software that enables one to chat with another person on a real-time basis. Video conferencing tools are becoming readily available to the common man.
Digital video or audio composition
Audio or video composition and editing have been made much easier by the use of computers. Graphics engineers can use computers to generate short or full-length films or even to create three-dimensional models.
Computers in Medicine: -
You can diagnose diseases. You can learn the cures. Software is used in magnetic resonance imaging to examine the internal organs of the human body. Software is used for performing surgery. Computers are used to store patient data.
Mathematical Calculations: -
With the help of computer you can perform over a million calculations per second we can perform the biggest of mathematical calculations.
Banks: -
To days all the bank provide online facility. All financial transactions are done by computer software at you home. They provide security, speed and convenience.
Travel: -
One can book air tickets or railway tickets and make hotel reservations online.
Telecommunications: -
The computer provide widely assistance to telecommunication department. There are many software which are widely used in the communication system. Also all mobile phones have software embedded in them.
Defense: -
There is many latest weapon which are automatically control through the computer system. Computer software also used for controlling the flight and targeting in ballistic missiles.
E-Learning: -
You can read and download the book , notes theses from internet and form digital library very easily with the help of internet.
Examinations
The online exam is another facility which is done by the computer technology. You can also check your examination results online.
Computers in Business: -
Almost all the shops maintain their database in computer and generate bills and also sale there things on the online Shops through internet . this all possible with the the development of computer technology.
News:
There are many websites through which you can read the latest or old news.
Home activity:
Today’s all the activity at home is done by the latest electronic devices which use the computer software for example automatic washing machines , micro Owen , TV system , cam etc
Today’s where computer technology is play a very important role in development and human life become easy on the other hand Computer and communication system can be used to assist in crime.
Computer crime which also some time called cyber crime or e-crime or electronic crime. Computer crime refers to any crime that involves a computer and a network. When any one use the computer in the commission of a crime then it’s called computer crime or cyber crime.
For this purpose Computer Misuse Act is designed to protect computer users against willful attacks and theft of information. According to that Act following are the some misuses of computer.
· Following are the some of the most popular example of cyber crime.
· Making or distributing child pornography.
· Hacking, threats, and blackmailing towards a business or person.
· Creating Malware - Writing, creating, or distributing malware program
· Some kind of Fraud through the computer online system for example Manipulating data, e.g. changing banking records to transfer money to an account.
· Deceiving individuals to gain private or personal information about that person.
· Distributed unsolicited e-mail to dozens or hundreds of different addresses which is called Spamming.
· Unauthorized access to systems you have no permission to access.
Computer virus is a special program or piece of special code that is loaded onto your computer without your knowledge and runs against your wishes and makes some damages in your computer.
All computer viruses are man-made and the hobby of mischievous person. The purpose of writing this type of program is
· Takes control of a computer and use it for specific tasks
· To generate money
· To steal sensitive information for example credit card numbers, passwords, personal details, data etc.
· To prove a point, to prove it can be done, to prove ones skill or for revenge purposes
· To cripple a computer or network
Some of the common virus is following:
File infector viruses infect program files. These viruses normally infect executable code, such as .com and .exe files. The can infect other files when an infected program is run from floppy, hard drive, or from the network. Many of these viruses are memory resident. After memory becomes infected, any non-infected executable that runs becomes infected. Examples of known file infector viruses include Jerusalem and Cascade.
Boot sector viruses infect the system area of a disk which contains the boot record. When computer is boot from this infected boot disk, then it’s may be damage the boot record and also cause to damage the other computer data.
Master boot record viruses:
A small program which is executed when a computer boots up, is called MBR master boot program. Typically, the MBR resides on the first sector of the hard disk. A master boot virus is a common type of virus that replaces the MBR with its own code. Since the MBR executes every time a computer is started, this type of virus is extremely dangerous.
A macro virus infects the Microsoft Word or similar application and causes a sequence of actions to be performed automatically when the application is started or something else triggers it.
A macro virus alters or replaces a macro, which is a set of commands used by programs to perform common actions. For example, the "open document" action in many word-processing programs relies on a macro to function, since there are several discrete steps in the process. Macro viruses change this command set, allowing them to execute whenever the macro is run.
Antivirus is a program which is specially design to prevent, detect and remove the malware virus infections from the computing devices. This program of antivirus often called Anti malware. When a virus is detected in your computer the antivirus program displays a warning asking what action should be done, often giving the options to remove, ignore, or move the file. There are many antivirus program available in market such that "Norton Antivirus , Kaspersky , semantic antivirus
Trojan horses are software programs that masquerade as regular programs, such as games, disk utilities, and even antivirus programs. But if they are run, these programs can do malicious things to your computer.
For example, a Trojan horse might appear to be a computer game, but once you double-click it, the program starts writing over certain parts of your hard drive, corrupting your data. While this is certainly something you want to avoid, it is good to know that these malicious programs are only dangerous if they are given a chance to run.
Virus Hoax
Virus hoax is an type of virus which come in form of a false warning (message) about a computer virus. Typically this warning arrives through in an e-mail. The Hoax virus typically uses emotive language in the warnings message and encourages readers to forward the message to other people as soon as possible. The Hoax virus send a message to user users that vital system files are viruses and encourage the user to delete these file.
Hacker: -
Hacker is a computer programmer who hacked the computer gain unauthorized access to computer systems. A hacker is very relevant to computer machine. He knows each technology of the computer hardware and also a very good programmer. The main target of hacker is trying to breach the security of networks, Web servers and email servers. Usually they use a selection of specialist software to identify weaknesses, which are then exploited. A Hacker never did cracking and stealing type of work.
Cracker: -
Cracker is related with software engineering. Cracker break into secure systems often on a network bypasses passwords break the software licenses. He breaches the commercial software licensing system illegally and registration techniques. These types of person crack the passwords of software and then use it illegally.
System development life cycle some time also called application development life-cycle is a chain and organizes process of developing new information system. The main purpose of system development lifecycle is produce high quality systems that meet the customer requirement. In SDLC we decided the customer requirements, overall system cost, time require, programming language, physical structure.
Following are the different phases of software development cycle:
System study
Feasibility study
System analysis
System design
Coding
Testing
Implementation
Maintenance
1. System Study: -
This is very first stage of the SDLC. This gives a clear picture of what actually the physical system is. System study is done in two phases. In the first phase preliminary survey of the system is done which helps in identifying the problem of the system and in second phase we study the running system in more detailed and in-depth and then identify the user’s requirement and the limitations and problems of the present system.
2. Feasibility Study
On the basis of result of the initial study, feasibility study takes place. The feasibility study is basically the test of the proposed system in the light of its workability, meeting user’s requirements, and effective use of resources and of course, and the cost effectiveness.
The main goal of feasibility study is not to solve the problem but to achieve the scope. This is very difficult stage because this step a feasibility report is submitted to heads approves the new system. Most of projects die in this stage.
3. System Analysis
When it is decided that new system will develop then the next phase is system analysis. Analysis involved a detailed study of the current system, leading to specifications of a new system.
In this step data will be collected with different data gathering technique and the analysis the data in depth. The system requirement will be estimated.
4. System Design
Next step is system design. This is real development of in which the entire previous decide concept project on real system. It is a most crucial phase in the development of a system. Normally, the design proceeds in two stages:
Preliminary or general design
Structure or detailed design
5. Coding
In this phase computer oriented works don. The whole system is to be converted into computer understanding language. This is some time called the programming phase in which the programmer converts the program specifications into computer instructions, which we refer as programs.
6. Testing
Before actually implementing the new system into operations, a test run of the system is done removing all the bugs, if any. It is an important phase of a successful system.
7. Implementation
After having the user acceptance of the new system developed, the implementation phase begins. Implementation is the stage of a project during which theory is turned into practice. During this phase, all the programs of the system are loaded onto the user's computer. After loading the system, training of the users starts. After the users are trained about the computerized system, manual working has to shift from manual to computerized working.
8. Maintenance
Maintenance is necessary to eliminate errors in the system during its working life and to tune the system to any variations in its working environment. It has been seen that there are always some errors found in the system that must be noted and corrected. It also means the review of the system from time to time.
Intelligence is the ability to meet the situation successfully by proper behavioral adjustment. For example a person considered being intelligent, if he can judge the situation from the surface that what is happening inside. Artificial intelligence is the branch in which we have to solve those problems, which require human intelligence. In simple word Artificial Intelligence is an area of computer science that related with the creation of intelligent machines that work and react like humans.
Objectives Of A.I (Artificial Intelligence):
The following are the main objectives of A.I.
1. To develop intelligent computer system, which will be more useful than current conventional computer system.
2. To explore and understand the basic principals of intelligence, so that intelligence can be programmed into computer system.
Some of the major characteristic of the AI system are:
· Intelligent computers can understand simple English,
· These can be used in traffic control system.
· These can be used in space exploration.
· These are used in farming.
· These are used in house hold activities.
1. Robotics
2. Expert System
3. Speech recognition
1. Robotics:
The field of computer science and engineering concerned with creating robots, devices that can move and react to sensory input. Robotics is one branch of artificial intelligence.
Robots are now widely used in factories to perform high-precision jobs such as welding and riveting. They are also used in special situations that would be dangerous for humans -- for example, in cleaning toxic wastes or defusing bombs.
Although great advances have been made in the field of robotics during the last decade, robots are still not very useful in everyday life, as they are too clumsy to perform ordinary household chores.
2. Expert System:
A software or a set of programmed that manipulate the programmed knowledge to solved problems in a specialized field that normally requires human expertise with special feature of explaining its conclusions and acquiring new knowledge.
Expert systems are part of a general category of computer applications known as artificial intelligence. To design an expert system, one needs a knowledge engineer, an individual who studies how human experts make decisions and translates the rules into terms that a computer can understand.
Expert system is composed of different components.
1. Knowledge base.
2. Inference engine.
3. Memory
4. User interface
Knowledge Base:
It is a stored collection of facts on a particular fields & thousand of IF- ELSE rules by which facts relate. Knowledge base is create by special designers
Called knowledge engineers. Knowledge engineers spend months working with human experts.
Inference Engine:
An inference engine is a reusable program that directs the implementation of knowledge. Inference engine decides how a rule is to be applied to a problem. Inference engine runs an expert system, determining which rules are to be invoked, accessing the appropriate rules in the knowledge base, executing the rules and determining when an acceptable solution is found.
Memory:
It holds the data temporarily" coming from inference engine or sends the stored data to inference engine.
User-Interface:
User-interface allows the user to communicate with expert, system. The communication performed by the user interface is bi-directional. The user asks question & describes problems and system responds with its recommendations
Examples Of Expert System:
Here are some examples of expert system.
MYCIN:
This expert system was developed to analyze different bacterial infections. It prescribed medical treatment. In this case, first of all bacterial expert Knowledge will be stored in computer. After this computer ask the different questions and suggest the drug on the basis of given answers,
Prospector:
It was developed for geology- Prospector was designed to analyze data collected from mineral sites to help in mineral exploration processes. Process of Prospector is same as geologist; collect the data and then make decision based on the collected data.
Eliza:
This expert system is capable to answer different, questions being asked. Let us consider, a patient of depression came to Eliza and Elisa treat him as a psychiatric. Elisa asked the questions and patient answered these questions.
Q: How do you feel?
A: I am depressed.
Q: I am sorry to hear you are depressed. Please mention some causes.
A: I failed in my Bsc. Examination. I feel very guilty. My parents are very angry with me.
As we know that computer development is one of the greatest scientific achievements of the 20th century. Computers are used in various fields as well as in teaching and learning. It is an important thing to people, especially the people who run organizations, industry, etc. Almost anything you know is run or made by computers. Cars and jets were designed on computers, traffic signals are run by computers, most medical equipment use computers and space exploration was started with computers. Most of the jobs today require the use of computers.
I think without computer we are again goes back in dark life.
Computer has a VERY important impact in our life on different aria:
1. Personal Impact:
2. Community Impact:
3. National Impact:
4. Global Impact:
5. Future Impact:
1) Personal Impact:-
It change our personal life our Privacy and personal rights. We have every thing in our control we have control in our data banks, computer terminals, which make our life, secure.
Computer has greater impact to solve the problem of Employment. Its create job opportunities in many aria.
Computer also make our Business transactions easy giving different facility just like Automated billing, credit cards, interact, consumer spending etc.
The replacement of people through automation
2) Community Impact: -
Computer solves the community problem and has greater impact on community. Solve Employment problem, make help in Traffic control, Urban planning and in Law enforcement.
3) National Impact: -
Computer provides wide and effective Communications media and other different filed which solve our national problem. For example the use of information for control. Make easy Vote counting, Electronic funds transfer, Stock-market transactions, Defense, Surveillance, National data banks, Employment, Shifting patterns, Telecommunications, Satellite broadcasting, The possibility of fraud or theft using computer based systems, Standards for computer hardware and software.
4) Global Impact : -
Reporting of current events, Communications media, World government, International standards, Exploration of space and sea, World wide access to data
5) Future Impact: -
in Future computer give greater facility and make our life easy. It impact our daily life in home in the home, in Gaming, Learning, Electronic mail, Shopping, Business transactions, Information processing, storage and retrieval, Effect on the family unit and on familiar patterns of life, Travel, Computer communication as a replacement for travel, Possible effects on the formal education system, The use of robots in industry and in the home, Teleprocessing networks, Communications networks.
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