What is a Search Engine?
Internet
The Internet is huge with billions of files and pages in every language and on every topic. For this reason people decided to index it to make it easier to find what you are looking for. At first this was done manually but due to the explosion of content, people could not keep up and automated search engines where born which would crawl the web looking for new content and indexing it as best they could.
These crawlers also called web bots are just servers that read the content of pages like we would read them using a web browser. They try to work out what the page is about, and then index them.
When you go to a search engine such as Google or Bing, you are presented with an input box where you type what you are searching for. In the test you submit, the search engine then trawls through the billions of indexed pages to find a best match to your query.
Today Google rules the search engines but there are many to choose from and although Google is the biggest, Bing and Yahoo also do a great job of it.
Over the years they have become very sophisticated and good and guessing what you are after. They try hard to make it very simple for you, allowing you to type in a question, and then present you with a list of pages the search engine thinks you are after.
What is a Web Address?
Internet
A web address is the location of a file on the web. They are called URLs.
See What is a URL?
What is The Web?
Internet
The Web or World Wide Web (WWW), is the part of the Internet made up of web pages with links (hyper links) to other pages on the Internet and written in a language called HTML which you need a web browser to read properly.
If you go to just about any website you will be taken to a page known as the homepage and from this page will be links to other pages. This simple concept of pages linking to other pages is the World Wide Web.
The web as we know it today was created by British engineer and computer scientist Sir Tim Berners Lee.
It is common to add the www prefix to domain names, but becoming less so. More often than not, you can leave out the www portion of a domain name and still get to the same website. The www part of the domain name is called a sub domain.
What is the Semantic Web?
Internet
Semantic means the meaning of. It has to do with what things mean. So the semantic of something is the meaning of that thing.
To human eyes the meaning of a link on the web might be self explanatory. It might be obvious that that a link to “What is The Big Web FAQ?” is going to take you to a definition of this site.
To a computer however, it is just a bunch of letters in the same way that Chinese is just a bunch of symbols to an Englishman.
The Semantic Web is where relationships such as links, are defined in a way that a computer can understand. In the previous example the simple word “definition” would tell a computer that the link takes us to a definition of what this website is about.
More than just links, the Semantic Web describes the relationships between things such as time, weight, distance, definition, popularity. Anything really.
What is a Web Bot?
Internet
A Web Bot or Web Robot is a bit of software that indexes websites for search engines such as Google or Bing. They read a page indexing it’s content. They then follow links form that page and index any other pages they can find.
Once a page has been “crawled” it is then made available on the search engine.
Also known as Web crawlers or Web spiders.
What is an E-book?
Software
E-book is short for electronic book. They are also called ebooks and digital books.
They are simply electronic versions of real books which use devices such as a PC, mobile phone and e-book readers (e-readers) to read them.
E-books come in many file formats but many use HTML as the language used to describe the document.
There is no definitive E-book format which can cause problems if you ever change e-reader.
What types of images are used on the web?
Design
Due to the limitations on files sizes used on the web thanks to downloading speeds, images need to be highly compressed to make them as small (in file size) as possible. A raw, uncompressed photo for example can be many megabytes in size, but when converted to a JPEG, be only kilobytes with little noticeable difference to the eye. For this reason only highly compressed image formats are used on the web.
Some image formats are static. Others can be animated. In the case of Flash and Silverlight, they can even have sound and video. The line between and image and movie is somewhat blurred when it comes to rich media formats such as Flash and Silverlight.
There are two types of image used on the web.
The common bitmaps are:
The common vector types are:
- SVG
- Flash
- Silverlight
What is a GIF file?
Design
GIF stands for Graphics Interchange Format.
GIF files or GIFs are an image file format commonly used on the internet. They are bitmap graphics and better suited to images with blocky colour and simple shapes and sharp edges, whereas a JPG bitmap graphic would be better suited photography and subtle shading.
They are also restricted to a palette of only 256 colours but do have other advantages over the JPG alternative which are lossless compression and animation.
When a GIF is compressed it does not lose any quality. This leads to less compression than a JPG can achieve.
In general GIF animations are short and simple due to the large file size but they are still very popular even with modern video alternatives. They do not store any sound data so GIF animations are always silent.
What is a Bitmap Graphic?
Design
Bitmap graphics, or just bitmaps, are image files that are built up using rows upon rows of coloured dots. They are also known as raster graphics.
These dots are called pixels. They are the bits in bitmap.
Common file formats for bitmaps are JPEG, GIF and PNG. These are all bitmaps but use alternative methods for compressing the data.
The alternative to bitmap graphics are vector graphics which use shapes rather than dots to define an image. Using bitmaps you can get a much more realistic image than a vector graphic, with all the shading and colour variations you would get in a photo. The downside however is that the image can’t be resized without losing quality. If you shrink it, it loses dots and loses that data forever. If you enlarge it, it just looks pixilated (each dot becomes a larger square).
When you take a photo using your digital camera, the data is stored in a long row of dots. These are the dots you then see on the screen as an overall image.
What is a Vector Graphic?
Design
A vector graphic is an image type that uses shapes to produce an overall image. Such files are built up using simple, coloured shapes/geometry to create an image.
Since they are based on mathematical formula they can be resized at will without the loss of quality seen with bitmap graphics.
SVG files are vector graphics. Flash and also Silverlight also use vector graphics.
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