Information Technology

The first thing that you need to understand is what a search engine “spider” is, and how it works. A "spider" (also known as a "robot" or "crawler") is a software program that search engines use to find what’s out there on the ever-changing web. There are a lot of different types of search engine spiders, but they all contribute to the overall goal of keeping their search engine’s index as accurate and up-to-date as possible. Not all spiders are operated by search engines, and some of these are a real nuisance.

The first type of spider is one that actually “crawls” the web looking for websites and pages. This program starts at a website, loads the pages, and follows the hyperlinks on each page. In this way, the theory goes, everything on the web will eventually be found,as the spider crawls from one website to another. Search engines run anywhere from dozens to hundreds of copies of their web-crawling spider programs simultaneously, on multiple servers.


When a "crawler" visits your home page, it loads the page’s contents into a database.With some spider programs, that’s all they do – load the home page, so that another spider can actually index it. Once your site has been found, the text of your page is loaded into the search engine’s index, which is a massive database of web pages. The last time I checked, both Google and FAST claimed to have over 2 *billion* pages indexed. Google has over 3 billion documents in its database.

Some search engines don’t do any more than load the home page, but this is becoming more rare. A search engine that only indexes your home page, or a few pages linked from it, is doing what’s known as a “shallow crawl.” Most search engines nowadays do a “deep crawl,” which means that they follow the hyperlinks on your home page, loading the pages they find, successively getting deeper into your site. Some of them have a limit on the number of pages they’ll index from a given site, others try to index everything.

There are other types of spiders as well. “404 spotters” are used by search engines to help avoid referring searchers to pages that no longer exist online. These spiders go through the search engine’s index page by page (or site by site), trying to load each page. If the page can’t be found, the web server returns a “404 error” which indicates that the page or site isn’t currently available online. When the spider (some of them will check later to verify that a page really is offline)
doesn't find a page, it’s deleted from the index. This is why it’s important to use a good web hosting provider. If your server is offline at the wrong time, your site may be dropped from a search engine’s index, and it can take several weeks before it’s indexed again.

Another term you may hear is “spider food.” This is shorthand for anything that’s placed on a web page (mostly hyperlinks) that is intended to attract a spider’s attention. Sometimes, these are invisible links that a web surfer would not find, and are intended to direct the spider to keyword-rich “doorway” or “hallway” pages specifically designed to fool the search engines.

I don’t use these kind of tricks, but you should be aware of them. I'll explain throughout this book why you should avoid using dirty tricks to fool the search engines. The first thing a spider is supposed to do when it visits your site is look for a file called “robots.txt”. This file contains instructions for the spider on which parts of the web site to index, and which to ignore. The only way to control what a search engine spider sees on your site is by using a robots.txt file. Chapter 8 provides detailed instructions on how to control spiders, and why you’d want to do this.

All spiders are supposed to follow certain rules, and the major search engines do follow these rules for the most part. One rule is that spiders should load only one page a minute – this rule came about when early spiders visited early web servers and tried to load entire web sites all at once. The result of this was that access for the site’s real visitors often slowed to a crawl. Since the web was much smaller then, a spider might visit your site several times a day! With modern, high-speed web servers, and spiders only visiting infrequently, this rule doesn’t make as much sense as it once did, but it’s
still followed.

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When we communicate we are sharing information. This sharing can be local or global. Between individuals, local communication usually occurs face to face, while global communication take place over distance. The term telecommunication, which includes telephony, telegraphy, and television, means communication at a distance (tele is Greek for "far").

Data commucation implies the transmission of information between two devices through a transmission medium. Data communication is considered local if the communicating devices are in the same building or a similarly restricted geographical area, and is considered global if the devices are farther apart.

A data communication system may be represented by way of a simple conceptual model as shown in fig .......

When we are in a new era of internet marketing, competition for the top ranking on any search engine has increased even more. In the huge spread of world wide web, the best way to get observed is through the search engines. And more or less every locations of web struggle for higher rankings in the SERP. This is the reason, you need to optimizing your site with more than one method for SE optimization. Building or collecting links is one of the most reliable and cost-efficient methods for increasing web visibility.

Link building campaign is the most vital part and its plays an essential role in SE optimization and also excellent traffic generate to a particular website and one of the most essential processes that impact your website's page ranking on any kind of search giant like as Google, Yahoo, Bing etc. At first a seo professional will strike the list by selecting an appropriate competitive keywords and key phrases.After selecting the right keyword experts are starting the back link campaign for the particular webpage. Incoming links are extremely important in structuring a high quality seo service.

Benefits of growing link popularity - Always you put a link on your Website to a different Website, you are referring more business to them. It is expected that your clients will also verify the business that you offer on your site and possibly do business as well with them.

Achieve superior search engine positions - When a search engine evaluates your Website, it's looking for all types of things about your site that move into its algorithm for position. One of these issues is the quality and number of back links from other sites to your website. Mainly, it reflects on a back link to your website as a reference. So the more references a site has, the top website can rank in SERP.

Link Building is one of the useful techniques of seo which can effectively increase the web attendance of your website. This technique of SEO involves posting links leading to your website on pages of other website. The host websites in turn back link to pages of your website. This is the procedure in which links are produced. It has come out itself into a complete industry, turnover with millions of dollars. These services can save your advertising expenditure and also your time.

As a professional Link Building India, we spread our hands with more than four years experience, for improving your business website. Our link exchange programs going through good Google page rank pages and search engine popular websites. So if you are searching for a good and reliable link building company then feel free to contact us and order for better campaign of your website.

All computers have certain common characteristics irrespective of their type or size.

• Word length: The digital computer works on BITS (Binary Digits) 0 and 1. A group of 8 such bits from a byte. Word length is the number of bits that the computer can process in a single clock tick or in unit time. Word lengths may be 8, 16, 32 or 64 Bits. The greater the word length, the greater is the speed of the computer.
• Speed: Computers work at very high speed much faster than humans. The speed of a computer is measured in clock cycles (Hertz). Millions of instructions can be executed in a second. Speed incresses with the power of the computer. For example supercomputers have computing speeds measured in Nanoseconds or Picoseconds.
• Accuracy: Speed without accuracy is of no use and so the accuracy in computers is very high. Errors do occur, but they are due to hardware errors (technological factor) or errors due to wrong user input (human factor).
• Storage Capacity: The computer can store large amount of data and information. The storage memory is either primary or secondary memory. The primary memory (Main memory) is used to store temporary data while the computer is in the runtime condition. The Secondary memory consists of storage devices which are use to store data permanently. The unit of storage is a Byte with the storage capacities of both primary and secondary memory described in bytes or its derivatives.
• Diligence: Being a machine, computer never gets bored or tired as in the case of human beings. It never gets exhausted repetitive tasks.
• Versatility: Computers have invaded ever field and are proving efficient in every work they do. Computers are versatile machines and they can do tasks from as simple as calculations to as complex as navigation of missiles and satellites.
• Versatility has been achieved in computers as they can do any job provided it is divided into logical steps.
• Security: Computers can provide security to the data. Many softwares provide security in the form of passwords to restrict to the data. This way unauthorized access can be limited.
• Automation: The level of Automation is phenomenal in Computers. Computers can be programmed to perform complex tasks automatically. The task is initiated once and the computer follows it to completion according to the programming logic. If programmed correctly, computers can be made to switch from program to program executed in a pre-defined sequence, switch on/off machines at the appropriate time, they can monitor operational parameters and also take corrective actions if the parameters cause errors.