Switchescome in many shapes and sizes. They are operated by muscle movements or breath control. For example, a pneumatic switch- known as a sip and puff
- allows someone with quadriplegia to control the PC by puffing and sipping air through a pneumatic tube. People with quadriplegia can also use sip and puff joysticks.
Finally, there's voice recognition, which allows the computer to interpret human speech, transforming the words into digitized text or instructions.
4. Translate the italicized paragraph and comment on your translation
At the top of the page is the URL address. URLmeans Uniform Resource Locator - the address of a file on the Internet. A typical URLlooks like this: http://www.bbc.co.uk/radio/.
In this URL,http:// means Hypertext Transfer Protocol and tells the program to look for a web page. www means world wide web. bbc.co.uk is the domain name of the server that hosts the website - a company based in the UK;other top-level domains are .com (commercial site), .edu (education), .org (organization) or .net (network); radio is the directory path where the web page is located. The parts of the URLare separated by . (dot), / (slash) and : (colon). Some sites begin ftp://, a file transfer protocol used to copy files from one computer to another.
The toolbar shows all the navigation icons, which let you go back one pageor go forward one page.You can also go to the home pageor stop the current transferwhen the circuits are busy.
Tab buttons let you view different sites at the same time, and the built-in search boxhelps you look for information. If the feed buttonlights up, it means the site offers RSSfeeds, so you can automatically receive updates. When a web page won't load, you can refresh the current page,meaning the page reloads (downloads again). If you want to mark a website address so that you can easily revisit the page at a later time, you can add it to your favourites (favorites in American English), or bookmark it. When you want to visit it again you simply click show favourites.
On the web page itself, most sites feature clickable image linksand clickable hypertext links.Together, these are known as hyperlinks and take you to other web pages when clicked.
Tour the Collectives of Cyberspace
The Internet isn't just about email or the Web anymore. Increasingly, people online are taking the power of the Internet back into their own hands. They're posting opinions on online journals - weblogs, or blogs; they're organizing political rallies on MoveOn.org; they're trading songs on illegal file-sharing networks; they're volunteering articles for the online encyclopedia Wikipedia; and they're collaborating with other programmers around the world. It's the emergence of the 'Power of Us'. Thanks to new technologies such as blog software, peer-to-peer networks, open-source software, and wikis, people are getting together to take collective action like never before.
eBay, for instance, wouldn't exist without the 61 million active members who list, sell, and buy millions of items a week. But less obvious is that the whole marketplace runs on the trust created by eBay's unique feedback system, by which buyers and sellers rate each other on how well they carried out their half of each transaction. Pioneer e-tailer Amazon encourages all kinds of customer participation in the site - including the ability to sell items alongside its own books, CDs, DVDs and electronic goods. MySpace and Facebook are the latest phenomena in social networking, attracting millions of unique visitors a month. Many are music fans, who can blog, email friends, upload photos, and generally socialize. There's even a 3-D virtual world entirely built and owned by its residents, called Second Life, where real companies have opened shops, and pop stars such as U2 have performed concerts.
Some sites are much more specialized, such as the photo-sharing site Flickr. There, people not only share photos but also take the time to attach tags to their pictures, which help everyone else find photos of, for example, Florence, Italy. Another successful example of a site based on user-generated content is YouTube, which allows users to upload, view and share movie clips and music videos, as well as amateur videoblogs. Another example of the collective power of the Internet is the Google search engine. Its mathematical formulas surf the combined judgements of millions of people whose websites link to other sites. When you type Justin Timberlake into Google's search box and go to the star's official website, the site is listed first because more people are telling you it's the most relevant Justin Timberlake site - which it probably is.
Skype on the surface looks like software that lets you make free phone calls over the Internet - which it does. But the way it works is extremely clever By using Skype, you're automatically contributing some of your PC's computing power and Internet connection to route other people's calls. It's an extension of the peer-to-peer network software such as BitTorrent that allow you to swap songs - at your own risk if those songs are under copyright. BitTorrent is a protocol for transferring music, films, games and podcasts. A podcast is an audio recording posted online. Podcasting derives from the words iPod and broadcasting. You can find podcasts about almost any topic - sports, music, politics, etc. They are distributed through RSS (Really Simple Syndication) feeds which allow you to receive up-to-date information without having to check the site for updates. BitTorrent breaks the files into small pieces, known as chunks, and distributes them among a large number of users; when you download a torrent, you are also uploading it to another user Adapted from BusinessWeek online