What Affects Oracle Performance?

Because one of the roles of the DBA is to anticipate, find, and fix performance problems, you must know what types of things affect performance. To understand why these things affect performance, you must first review the basics of how a computer system works.

This is the main part that affecting your Computer:

Overview of Computer Architecture

Your computer system consists of thousands of individual components that work in harmony to process data. Each of these components has its own job to perform, and each has its own performance characteristics.

The brainpower of the system is the Central Processing Unit(CPU), which processes all the calculations and instructions that run on the computer. The job of the rest of the system is to keep the CPU busy with instructions to process. A well-tuned system runs at maximum performance if the CPU or CPU are busy 100% of the time.

So how does the system keep the CPUs busy? In general, the system consists of different layers, or tiers, of progressively slower components. Because faster components are typically the most expensive, you must perform a balancing act between speed and cost efficiency.

CPU and Cache

The CPU and the CPU’s cache are the fastest components of the system. The cache is high-speed memory used to store recently used data instructions so that it can provide quick access if this data is used again in a short time. Most CPU hardware designs have a cache built into the CPU chip. This internal cache is known as a Level 1 (or L1) cache. Typically, an L1 cache is quite small-8-16KB.

When a certain piece of data is wanted, the hardware looks first in the L1 cache. If the data is there, it’s processed immediately. If the data is not available in the cache, the hardware looks in the L2 cache, which is external to the CPU chip but located close to it. The L2 cache is connected to the CPU chip(s) on the same side of the memory bus as the CPU. To get to main memory, you must use the memory bus, which affects the speed of the memory access

CPU Design

Most instructions processing occurs in the CPU. Although certain intelligent devices, such as disk controllers, cam process some instruction, the instructions these devices can handle are limited to the control of dada moving to and from the devices. The CPU works from the determine how quickly these instructions are executed.

The CPU usually falls into one of two groups process:

Complex Instructions Set Computer(CISC)or
Reduced Instructions Set Computer(RISC).

Overview of Computer Architecture

Your computer system consists of thousands of individual components that work in harmony to process data. Each of these components has its own job to perform, and each has its own performance characteristics.

The brainpower of the system is the Central Processing Unit(CPU), which processes all the calculations and instructions that run on the computer. The job of the rest of the system is to keep the CPU busy with instructions to process. A well-tuned system runs at maximum performance if the CPU or CPU are busy 100% of the time.

So how does the system keep the CPUs busy? In general, the system consists of different layers, or tiers, of progressively slower components. Because faster components are typically the most expensive, you must perform a balancing act between speed and cost efficiency.

CPU and Cache

The CPU and the CPU’s cache are the fastest components of the system. The cache is high-speed memory used to store recently used data instructions so that it can provide quick access if this data is used again in a short time. Most CPU hardware designs have a cache built into the CPU chip. This internal cache is known as a Level 1 (or L1) cache. Typically, an L1 cache is quite small-8-16KB.

When a certain piece of data is wanted, the hardware looks first in the L1 cache. If the data is there, it’s processed immediately. If the data is not available in the cache, the hardware looks in the L2 cache, which is external to the CPU chip but located close to it. The L2 cache is connected to the CPU chip(s) on the same side of the memory bus as the CPU. To get to main memory, you must use the memory bus, which affects the speed of the memory access

CPU Design

Most instructions processing occurs in the CPU. Although certain intelligent devices, such as disk controllers, cam process some instruction, the instructions these devices can handle are limited to the control of dada moving to and from the devices. The CPU works from the determine how quickly these instructions are executed.
The CPU usually falls into one of two groups process:

Complex Instructions Set Computer(CISC) or
Reduced Instructions Set Computer(RISC).

HP Web Connected Home Printer

HP Web Connected Home Printer

HP has unveiled a web-connected printer designed to let consumers access and print content directly from the web without the need to turn on their PC.

The HP Photosmart Premium with touchSmart Web is claimed as the world’s first web-connected home printer. The inkjet device features a 4.33 in touch-screen display, through which users can connect to content available on the web.

According to HP, the device will allow consumers to print customized content from news sites, search for movies showing in their local area and book and print tickets in advance, as well as print photos directly from the web.

Inside the device is a new web-based printing platform using custom applications to access content. Buyers will receive some apps ready loaded on the printer, and will be able to download new ones published on an HP Apps Studio site.

“By giving access to the content they want at the touch of a finger, the ability to customize their printing experience and create their own apps, and enabling easy ‘one touch’ wireless setup, we are driving a significant shift in how people will be printing in the future,” said HP’s vice president Vyomesh Jishi.

The initial partners providing content are mostly US-based, including Google (Google Maps, USA Today, Coupons Inc, Nickelodeon, Web Sudoku and Weathernews Inc.

HP said that users of its Snapfish photo sharing service will be able to print photos directly from their account, and also from the HP Creative Studio web site for custom greetings cards, calendars and stationary.

The HP Photosmart Premium with TouchSmart Premium with TouchSmart Web has print, fax, copy and scan capabilities, and wired and wireless connectivity options.

Users can print directly from Wi-Fi-enabled PCs, Bluetooth-enabled devices and Apple’s iPhone and iPod touch, according to HP. The Indian pricing and launch date is yet not known.

Java Virtual Machine Feature

The following section provides a more comprehensive discussion of the three main task performed by the Java Virtual Machine.

• Code Lode by class loader

The class Loader loads all classes needed for the execution of a program. The class loader adds security by separating the namespaces for the classes of the local file system from those imported from network sources. This limits any Torjan Horse application, because local classes are always loaded first.

• Verifier Code by Bytecode Verifier

Java software codes passes several tests before running on your machine. The JVM puts the code through a bytecode verifier that tests the format of code fragments and checks code fragments for illegal code, which is code that gorges pointers, violates access rights on objects, or attempts to change object type.

* Verification Process-

The bytecode verifier makes four passes on the code in a program. It ensures that the code adhere to the JVM specifications and does not violates system integrity. If the verifier completes all four passes without returning an error message, the following is ensured:



• The classes adhere to the class file format of the JVM specification.



• There are no access restriction violations.



• The code causes no operand stack overflows or underflows.



• The types of parameters for all operational codes are correct.



• No illegal data conversions, such as converting integers to object

references, have occurred.

Java Technology

The java technology is:

1) Programming Language.

2) Development environment.

3) Application environment.

4) Deployment environment.

The syntax of the Java programming language is similar to C++ syntax You can use the java Programming language to create all kinds of applications that you could by using any conventional programming language.

As a development environment, java technology provides you with a large suite of tool: a compiler, an interpreter, a documentation generator. A class file packaging tool, and so on.

The java programming language is using usually mention in the context of the World Wide Web and browsers that are capable of running programs called applets. Applets are programs written in the Java programming language that reside on web servers, are downloaded by a browser to a client’s system, and are run by that browser. Applets are usually small in size to minimize download time and are invoked by a Hyper Link Markup Language (HTTP) web page.

Java technology applications are standalone programs that do not require a web browser to execute. Typically, they are general-purpose programs that run on any machine where the java runtime environment (JRE) is installed.

There are two main deployment environments. First, the JRE supplied by the Java 2 Software Development Kit (Java 2 SDK) contains the complete set of classes, GUI component classes, am advanced Collection API, and so on. The other main development environment is on your web browser. Most commercial browser supply a Java technology interpreter and runtime environment.

Java Technology Features

1) Java Virtual Machine (JVM) :

An good machine that is implemented by emulating it in software on a real machine. Code for the JVM is stored in .class files, each of which contain code for tat most public class.


The Java Virtual Machine Specification provide the hardware platform specifications to which you compile all java technology code. This specification enables the java software to be platform-independent because the compilation is done for a generic machine, known as the JVM. You can emulate this generic machine in software to run on various existing computer systems or implement it in hardware.

The compiler takes the Java application source code and generates bytecodes. Bytecodes are machine code instructions for the JVM. Every Java technology interpreter, regardless of whether it is a Java technology development tool or a web browser that can run applets, has an implementation of the JVM.

The JVM specification provides concrete definitions for the implementation of the following: an interaction set (equivalent to that of a central processing unit ‘CPU’ a register set, the class file format, a runtime stack, a garbage-collected leap, a memory area, fatal error reporting mechanism, and high-precision timing support.

The code format of the JVM machine consists of compact and efficient bytecodes. Programs represented by JVM bytecodes must maintain proper type discipline. The majority of type checking is done at compile time.

Any complaint Java technology interpreter must be able to run any program with class files that conform to the class file format specified in The Java Virtual Machine Specification.

The JVM design enables the creation of implementation for multiple operating environments.

Garbage Collection

Many programming languages permit the memory to be allocated memory varies based on the syntax of the language, but always returning a pointer to the starting address of a memory block.

After the allocated memory is no longer required (the pointer that references the memory has gone out of extent), the program or runtime environment should de-allocated the memory.

In C, C++, and other languages, you are responsible for de-allocating the memory. This can be a difficult exercise at times, because you do not always known in advance when memory can crash eventually when there is no memory left on the system to allocate. These programs are said to have memory leaks.

The java programming language removes you from the responsibility of de-allocating memory. It provides a system-level thread that tracks that each memory allocating. During idle cycles in the JVM, the garbage collection thread checks for and frees any memory that can be freed.

Garbage collection happens automatically during the lifetime of java technology program, eliminating the need to deallocate memory and avoiding memory leaks. However, garbage collection schemes can vary dramatically across JVM implementation.

Different Between C# and JAVA

Like C#, Java was also derived from C++ and therefore they have similar toots. Moreover, C# was developed by Microsoft as an alternative to Java from web programming. C# has borrowed many good features from Java, which has already become a popular language. However, there exist a number of difference between C# and Java.

1.
C# has more primitive data types.

2.
although C# uses .NET runtime that is similar to Java runtime, the C# compiler
produces an executable code.

3.
Unlike Java, all C# data types are objects.

4.
Array are declared differently C#.

5.
Although C# classes are quite similar to java classes, there are a few
important difference relating to constants, base classes and constructors,
static constructors, versioning, accessibility of members etc.

6.
Java uses static final to declare a class constant while C# uses use const.

7.
The convention for java is to put one public class in each file and in fact,
some compilers require this. C# allows any source file arrangement.

8.
C# supports the struct type and java does not.

9.
Java does not providing operator overloading.

10.
In Java, class members are virtual by default and method having the same name in
a derived class overrides the base class members. In C#, the base member
is required to have the virtual keyword and the derived member is required to use
the override keyword.

11.
C# providing better versioning support than Java.

12.
C# provides static constructors for initialization.

13.
C# provide built-in delegates and events. Java uses interfaces and interfaces
and inner classes to achieve a similar result.

14.
In Java, parameters are always passed by value.
C# allows parameters to be passed by reference by using the ref keyword.
15.
C# adds internal, a new accessibility modifier. Members with
internal accessibility can be accessed from other classes within the
same project, but not from outside the project.

16.
C# include native support for properties, Java does not.

17.
Java does not have directly support enumerations.

18.
Java does not directly support enumerations.

19.
Both Java and C# support interfaces. But, C# does not allow type
definitions in interfaces, while Java interfaces can have const type data.

20.
In java, the switch statement can have only integer expression, while C#
support either an integer or string expressions.

21.
C# does not allow free fall_throuhg from case to case.

22.
C# provides a fourth type of integration statements, foreach for quick and
easy iterations over collections and array type data.

23.
Catch blocks should be ordered correctly in c#.

24.
C# checks overflows using checked statements.

25.
C# uses is operator instead of instanceof operator in java.

26.
C# allows a variable number of parameters using the params keyword.

27.
There is no labeled break statement in c#. the goto is used to achieve this.

Different Between C# and C++

What is different between c# and c++

1)
C# compiles straight from source code to executable code,
with no object files.

2)
C# does not separate class definition from implementation.
Class are defined and implemented in the same place and therefore there is
no need for header files.

3)
Command-line parameters array behave differently in c#
as compare to c++.

4)

In c#, class definition does not use a semicolon at the end.

5)

C# does not support multiple code inheritance.

6)

Casting in c# is much safer than in c++.

7)

When overriding a virtual method, we must use the override keyword.

8)

Abstract methods in c# are similar to behave differently in
c# as compared to c##.

9)

C# provides special syntax to initialize arrays efficiently.

10)
Array in c# are always reference types rather than value
types, as they are in c++ and therefore stored in a heap.

11)

In c#, switch can also be used on string values.


12)

C# does not support the labeled break and therefore jumping out of nested loops can be messy.

13)

The set of operators that can be overloaded in c# is smaller compared to c++.

14)

C# does not provide any defaults for constructors.

15)

Destructors in c# behave any defaults for constructors.

16)

In c#, class and definition does not use a semicolon at the end.

17)

The first characters of the Main() function is capitalized. The Main must return either int or void type value.

18)

C# does not support #include statement. (Note that using is not the same as #include).

19)

All the basic value types will have the same size on any system. This is not the case in c or c++. Thus c# is more suitable for writing distributed application.

20)

In c#, data types belong to either value types (which are created in a stack) or reference types(which are created in a heap).

21)

In c#, structs are value types.

22)
C# checks for uninitialized variables and gives error massages at compile time. 23) In c++, an uninitialized variable goes undetected thus resulting in unpredictable output.

24)

In c#, supports a native string type. Manipulation of strings are easily.



http://wschools.blogspot.com

Introduction of C# Programming Langage

Introduction:

Programming contains the series of commands that create software. In general, a language that is encoded is binary numbers or a language similar to binary numbers that a computer’s hardware understands in understood more quickly by the computer. A program written in this type of language also runs faster. Languages that use words or other commands that reflects how humans think are easier for programmers to use, but they are slower because the language must be translated first so the computer can understand it.

Introduction C#

C# is a new computer-programming language developed by Microsoft Corporation, USA. C# is a fully object-oriented language like Java and is the first Component-oriented language. It has been designed to support the key features of .NET Framework, the new development platform for building component-based software solution.

It is a simple, efficient, productive and type-safe language derived from the popular C and C++ languages. Although it belongs to the family of C/C++, it is a purely objected-oriented, modern language suitable for developing Web-based application.

There are some features of C#.

* Major parts of .NET Framework are actually code in C#.
* It is a brand new language derived from the C / C++ family.
* It simplifies and modernizes C++.
* It will become the language of choice for .NET programming.
* It embodies today’s concern for simplicity, productivity and robustness.
* It is intrinsically object-oriented and web-enabled
* It is a concise, lean and modern language.
* It is the only language designed for the .NET Framework.
* It is the only component-oriented language available today.

Characteristics of C#

The language that is designed for both computing and communications is characterized by several fey feature. It is.

• Object Oriented
• Consistent
• Modern
• Simple
• Type-safe
• Versionable
• Flexible
• Compatible

Mouse

The tangible, visible, and material parts of a computer or other system is know as Hardware of system. Computer hardware comprises of electronic components, such as, CPU and monitor.

There are two types of hardware devices input and output:

Mouse:

A mouse is an input device that is important for graphical user interface because you can simply point to options and click a mouse button. These types of applications are often called point-and-click programs. A mouse may have one, two, or three buttons. The function of each button is determine by the program that uses the mouse.

Moving the mouse on a flat surface produces a corresponding movement of a pointer on the screen. “A mouse may be classified as a mechanical or an optical mouse, on the basis of the technology it uses. In a mechanical mouse, the ball that projects through the bottom surface rotates as the mouse is moved along a flat surface.

The direction of rotation is detected and relayed to the computer by the switches inside the mouse.


If am talking about optical mouse than, An optical mouse uses a light beam instead of a rotating ball to detect movement across a specially patterned mouse pad. MSC Corporation makes the optical mouse that uses Light Emitting Diode (LED) and photo-detectors to trap movement.

Types of mouse:

1)Trackball Mouse

2)Joystick Mouse

3)Light Pen Mouse

4)Wireless Mouse

5)Touch Pad Mouse

How to Add URL on the Search Engine

To enable other users to view the content on your website and make it easily accessible to end users looking for information about particular topics discussed in your website, you need to add your website to search engine. This is similar to advertising products in a newspaper that addresses a large customer base.


This registration process followed by most of the search engines is quite simple. To register your website, you are required to fill an online from and enter the URL of your website. Search engines offer paid as well as free submission of URLs paid submissions ensure that the URL of a website will appear if the contents of the website match with the specified keywords. In free submissions, search engines may take several weeks to include the website information in their database. You can submit the URL of a websites at Google through the http://www.google.com/addurl.html URL.




The following figure displays the Add your URL to Google Web page of the Google website.

1) First you will open google.com.

2) Type URL on the URL bar http://www.google.com/addurl/?continue=/addurl
3) Type your URL in URL box like URL is http://wschools.blogspot.com
4) Type your comments in BOX.
5) Type CAPTCHA code.
6) SUBMIT.

Searching Specific Content On the Google

Wschools.blogspot.com







You can customize your search for information on the Web to return the URLs for the websites that display only images, people information, mailing lists, and newsgroups. Specific features of the search engine that are used to display these features are.




Searching for Graphics:








If you want only images pertaining to the text string you enter in the search field to be displayed, you can make use of the images hyperlink provided by the Google and

AltaVista search engines. The images hyperlink is available on the home page of the website. When you enter any search string in the search text box, the result Web page displays a collection of graphics and their sources and not the text of the Web page.

For example,
to search for the images related to different facial expressions.





1)Open Internet Explorer and Type http://www.google.com in the Address Bar.

2)Click the Images hyperlink on the Google website home page.

3)Type Expressions in the search text box.





Searching Specific for People:

You can locate personal information, such as the house addresses, e-mail addresses, and phone numbers, of individuals by using search engines, Some search engines that provide this feature are:



•

Yahoo! People Search http://people.yahoo.com

•

Find Person at
•

http://find.person.superpages.com/
Switchboard at http://www.switchboard.com
•

Search Websites Companies http://www.blogstrom.co.uk


These websites maintain their database through one of the following sources:

•
Telephone directories

•
Public directories



Searching Mailing Lists:








You can send e-mails to a certain group of people to promote your products of services by using mailing lists. There are websites that enable search for mailing lists on the Internet. You can access http://www.topica.com to use free discussion lists.



This website offers over 40,000 lists. Consider the following example. Steve is working as Marketing manager with a company that deals in aircraft spare parts. Steve needs to promote the products and services of his company to various airlines. To do this, he needs to performs the following steps




1. Open Internet Explore and type http://lists.topica.com in the Address Bar.
2. Type airlines in the Search text box.
3. Click the Search button to display the following results.





Searching Groups:














To find a group of your interest, you can type the name of the group in the search text box or browse the links from the Groups Web page. This will display a list of subgroups. When you click a particular subgroup, a date-wise listing of the recent subjects for that group is displayed. If you click on any subject name, the most recent posts on the subject will appear.


Advance Search:








You can optimize searches to retrieve more precise results using different search operators as well as the advanced features offered by various search engines. These search operators also known as Boolean operator help you to specify additional parameters for the type of information based on a combination of several text strings.

The following Boolean operators that are commonly used in search phrase.






Searching With Operator

1) (And or +):

Search for the Web pages that contain each of the specified words. Example, The search string Mars AND Saturn AND Jupiter will search for the websites or Web pages that contain information about all the specified terms, Mars, Saturn, and Jupiter. The same search string can also be written as Mars + Saturn + Jupiter.


2)(Or):

Searches for the Web pages that contain any of the specific words. Example, The search string, Mars or Jupiter, will search for documents that contain information about Mars or Jupiter or both.


3)(Not or-):

Search for the Web pages that contain the information about the word specified before the NOT operator and does not search for the Web pages that contain the information about the word specified after the NOT operator.


4)Quotation Marks(“”) :

Searches for the Web pages that contain the exact phrase. Example, The search string “Life on Mars”, will search for the websites or Web pages that contain the exact phrase, “Life on Mars”.

Searching Specific Content On the Google

You can customize your search for information on the Web to return the URLs for the websites that display only images, people information, mailing lists, and newsgroups. Specific features of the search engine that are used to display these features are.


Searching for Graphics:


If you want only images pertaining to the text string you enter in the search field to be displayed, you can make use of the images hyperlink provided by the Google and AltaVista search engines. The images hyperlink is available on the home page of the website. When you enter any search string in the search text box, the result Web page displays a collection of graphics and their sources and not the text of the Web page. For example, to search for the images related to different facial expressions.


1)
Open Internet Explorer and Type http://www.google.com in the Address Bar.

2)
Click the Images hyperlink on the Google website home page.

3)
Type Expressions in the search text box.


Searching Specific for People: You can locate personal information, such as the house addresses, e-mail addresses, and phone numbers, of individuals by using search engines, Some search engines that provide this feature are:


•Yahoo! People Search http://people.yahoo.com
•Find Person at http://find.person.superpages.com/
•Switchboard at http://www.switchboard.com
•Search Websites Companies http://www.blogstrom.co.uk



These websites maintain their database through one of the following sources:

•Telephone directories
•Public directories


Searching Mailing Lists:

You can send e-mails to a certain group of people to promote your products of services by using mailing lists. There are websites that enable search for mailing lists on the Internet. You can access http://www.topica.com to use free discussion lists. This website offers over 40,000 lists. Consider the following example. Steve is working as Marketing manager with a company that deals in aircraft spare parts. Steve needs to promote the products and services of his company to various airlines. To do this, he needs to performs the following steps


1.Open Internet Explore and type http://lists.topica.com in the Address Bar.
2.Type airlines in the Search text box.
3.Click the Search button to display the following results.

Searching Groups:

To find a group of your interest, you can type the name of the group in the search text box or browse the links from the Groups Web page. This will display a list of subgroups. When you click a particular subgroup, a date-wise listing of the recent subjects for that group is displayed. If you click on any subject name, the most recent posts on the subject will appear.

Advance Search:

You can optimize searches to retrieve more precise results using different search operators as well as the advanced features offered by various search engines. These search operators also known as Boolean operator help you to specify additional parameters for the type of information based on a combination of several text strings.


The following Boolean operators that are commonly used in search phrase.

1)(And or +):

Search for the Web pages that contain each of the specified words.
Example

The search string Mars AND Saturn AND Jupiter will search for the websites or Web pages that contain information about all the specified terms, Mars, Saturn, and Jupiter. The same search string can also be written as Mars + Saturn + Jupiter.

2)(Or):

Searches for the Web pages that contain any of the specific words. Example, The search string, Mars or Jupiter, will search for documents that contain information about Mars or Jupiter or both.


3)(Not or-):

Search for the Web pages that contain the information about the word specified before the NOT operator and does not search for the Web pages that contain the information about the word specified after the NOT operator.


4)Quotation Marks(“”) :

Searches for the Web pages that contain the exact phrase. Example, The search string “Life on Mars”, will search for the websites or Web pages that contain the exact phrase, “Life on Mars”.

Using Search Engine for Search

You can use the carious options provided by a search engine to search for relevant and specific information quickly. For Example, Google provides options, such as Images, Catalogs, Groups, and Directory searches to search for specific information effectively.

Yahoo is also providing many types of search options.

Search Indexes

Search engine are programs that enable you to search for information using indexes. The indexed information can be retrieved quickly. This is similar to using the index of a book to locate the page number corresponding to a particular topic in the book.
There are three types of indexes:

1)Static Index:

Is specific to a website and updated less frequently as compared to the other types if indexes. It also known as a site map on a website. A static index allows users to manually search information through the directories of the indexed information.

2)Keyword Index :

Is based on the keywords of the Web Page. A keyword index allows users to enter any text string to be searched. This text string is then compared with the keywords maintained by the search engine for the Web page. If the keywords correspond to the searched string, the relevant indexed information is retrieved for the users.

3)Full-Text Index:

Contains information about each word of every Web page. A full-text index allows users to enter any phase to be searched. The phrase is then compared with the exact words on the Web page. If the words correspond to the searched string, the relevant indexed information is retrieved for the users.

Earlier versions of search engine would return search result only for Web pages in the HTML format. All the major present-day search engines, such as Google and alta vista, support various file formats, such as PDF, PowerPoint, Spreadsheet, and Flash for searching. The common file formats supported by search engines are:

1)Adobe Portable Document Format (.pdf)
2)Microsoft Excel PowerPoint (.ppt)
3)Microsoft Excel (.xls)
4)Adobe PostScript (.ps)
5)Microsoft Word (.doc)

How to Work Search Engine

Search engine

use programs that gather Web pages that are relevant to the keyboard specified in the Search text box. These programs are called spiders or crawlers. Spider programs visit a Web page, red the information present on the Web page, interpret the keyboards on the Web page, and follow the link connected to the Web page.

The information in the central search database is indexed. Landing refers to the process of examining the contents and determining the relevance of the information contained on the Web page. The different components of a Web page that are searched to create indexes include the contents of the title and the keyboard, titles of the links, and the text inside the account.


After the Web page is analyzed for its contents, it is ranked in relation to the other Web pages that contain information on similar subjects. The algorithm to rant Web pages differs from one search engine to another.
When end user submit the keyboard or combination of keyboards to the search engine, the information is searched in the central search database and the results are returned to the end users.

Former Search Engine Tools

A variety of text-based search tools were used to archive, locate, and download files and resources from the Internet. Some of these tools includes Gopher, Archie, and Veronica.

Gopher :

Gopher was a text-based document-retrieval Internet application that used to browse and search for information on Internet servers. The application was developed at the University of Minnesota and named after the school’s mascot, the Golden Gopher. A gopher server display the documents stored in its database in a hierarchical structure Gopher severs are not functional anymore. The contents in the Gopher database have been converted into websites that can be easily accessed through the current search engines.

Archive

Archive was an Internet application that conducted searches for the files available at client or a Telnet client to search for files. After the results were presented, the files could be downloaded through an FTP client. Most Archie servers are no longer functional.

Veronica

Veronica is an acronym for Very Easy Rodent Oriented Net-wide Index of Computerized Archives. This search utility was developed at the University of Nevada. It was used to find information on gopher servers. Veronica allowed users to enter keyboards to search the gopher site for files, directories, and other resources.

Introduction of Search Engines

Search engines

are websites that allow users to search information on the basis of keywords or a combination of keywords. For example: If I want music related information than, I will search music as a key word.

A search engine takes the keyword to be searched as the search string and returns the URLs of the websites that contain information on the object specified. This is similar to a librarian who guides you towards a particular section of books for reference after you specify the topic that you are looking for.

Thus, search engine are the key for locating information on the ever-expanding Internet. Without the use of search engines, locating information on a specific topic would be time consuming and cumbersome because one would not be able to gather information from all the possible sources available on the Internet.

Most popular search engine are:

1)http://www.google.com Google
2)http://www.lycos.com Lycos
3)http://www.yahoo.com Yahoo
4)http://www.hotbot.com HotBot
5)http://www.altavista.com Alta Vista

Primary Services of Internet

Primary Services of Interne


The power and potential of the Internet is unlimited. During the past few years the Internet has grown at an exponential rate, thus providing netizens with many services. A few a of them:

1.Email

2.File Transfer Protocol (FTP)

3.Finger Service

4.Games

5.Mailing List

6.Remote Login

7.Bulletin Board System(BBS)

8.World Wide Web (WWW)

9.Internet Relay Chat (IRC)

10.Electronic Magazines.

Use of the Internet

1)Employment Opportunities:

The Internet opens up a web of employment opportunities. As e-commerce is making rapid strides in India, and more and more companies are logging on to the Internet, many career opportunities have been created like that of web administrator, web designer, web developer, web page hosting administrator, web designer, web developer, web page hosting, e-commerce, and consultation groups.

2)Great Speed and Good Information Flow:

An MCA students was looking for job opportunities in IT companies. By 12 p.m., she had identified five interesting jobs to which she e-mailled her resume and faxed some additional information which information required in company. Within three house, she received from three companies information regarding personal interview. Had conventional methods been used, the entire process would have taken a few days to a few weeks.

3)Entertainment:

The internet provides a wide of entertainment like, movies, music, and games. In fact, there are certain screen savers that provide good quality music so much that you going to the website www.screen.com). Another websites www.google.com provides you lats of information about entertainment.

4)Business by Internet:

E-commerce is the killing application of the Internet, where all sorts of business function like ordering of items, making quotations, payment of bills, exchange of business document take place. The place the only thing that is not possible on the Internet is the actual supply of goods apart from documents and software.


5)Good Communication:

Communication is the keyword today. In fact, due to this capability the word seems to get smaller all the time. Letters, telegrams, faxes are all one way communication but the Internet offers a huge variety in the types of information exchange, namely interactive, off-line, one-to-one communication, one to many communication, and so on.


6)Reduction of Uncertainty:

Faster access to information brings the latest technique and technologies at your doorstep thus increasing productivity. Uncertainty in mailing addresses, etc., have diminished as an organizational or a residential address may change but the person can still be connected as his e-mail; identity remains the same Of course, if the e-mail address is abandoned, then tracing a person would be next to impossible.

Administration and Ownership of Internet

One think is certain nobody owns the Internet, nobody funds it. In fact, every person who gets connected to the Internet becomes a part of the Internet family. The Internet is not administered by any center body.

Many committees are working in teams to constantly maintain the internet and promote communication on the Internet. It appoints the Internet Arch Board which authorizes standards and allocates and keeps a record of Internet resources (like IP addresses). Internet Engineering is another voluntary group which handles technical problems. Coordination function of domain names to help cover administrative costs.

Computer Emergency Response Team (CERT) Jooks after security matters. There are many more voluntary bodies and the underlying concept of communication on the internet is that the local area networks are interconnected regionally. These regional networks are connected to a backbone.
These backbones are interconnected to each other at gateways. Gateways basically translate data from one kind of network to another.

Definition of Internet

Introduction :

In 1970s the Defence Department of USA set up a network called ARPANETT(Advance Research Project Agency Network). The main objective was to provide aid to military research results, scientific teams at Defence In order to share information and research results, scientific teams at Defence Ministry of US and a few selected universities and research laboratories collaborated.


Slowly word spread about the advantage of collaborative work and more research teams and equipment manufactures started forming network teams. As the networks started growing, never protocols like TCP/IP protocol (a set of protocols that help in communication over the Internet)
Evolved in which communication could take place between machine of different configuration and types>