| Cache | Cache and caching are terms found throughout the computer world. A cache is a temporary store, intended to speed up and/or smooth out the communications between computers or between parts of a computer. Browsers usually have a cache, in which they store all the parts of recently-accessed Web Pages in case they are needed again. Some browsers make better use of their cache than others; Opera is particularly good. A Proxy Server is also a type of large, sophisticated cache. |
| Case Sensitive | The requirement to be exact about the use of upper case letters (capitals) and lower case. Most commonly this will be found in relation to Passwords and Web Site Paths (URLs or URIs). E.g. a case sensitive Application will see RS-infotech, rs-infotech and Rs-InfoTech as three different words, only one of which may be correct. Note that Internet E-mail Addresses are never case sensitive, but Web site addresses can be (and often are) case sensitive after the first Slash ("/"). |
| Cat 5 | Short for Category 5 - See Category 5. |
| Cat 5e | Short for Category 5 Enhanced - See Category 5e. |
| Category 5 | A network cabling specification, the minimum standard that schools should consider installing. Allows up to 100Mbs (Fast Ethernet) networking. A proper Category 5 installation requires both Category 5 components and correct installation. |
| Category 5e | Short for Category 5 Enhanced, a network cabling specification, the current "desktop" standard that schools should consider installing. Allows up to 1Gbs (Gigabit Ethernet) networking. A proper Category 5e installation requires both Category 5e components and correct installation. The requirements of the "Enhanced" specification are more stringent than the basic one, to cater for the higher transmission frequency of Gigabit Ethernet. |
| CC | Carbon Copy - E-mail terminology for "send a copy to...". You would put someone's name in the CC list (rather than the "To" list) if the e-mail is not addressed to them but you would like them to read it anyway. To send a circular to a list of people, it is usually preferable to use the "BCC" list to protect the recipients' right to privacy. |
| CGI | Common Gateway Interface - Loosely used to mean programs that run on a Web Server. If your Web Site Hosting provides CGI access, it usually means that you are able to create a more sophisticated site. For instance you could have a guest book or a message board, or something much more complex. There are thousands and thousands of free CGI programs (or "scripts") available on the Internet, but be prepared for a bit of tinkering and trial and error if you fancy a dabble. CGI scripts can be written in any language that your Host supports; the most common are probably Perl and PHP. Most providers of "free" Web Space do not provide a proper CGI facility, but it should be part of any paid-for hosting package. |
| Chat Room | One of the many ways of spending your time on the Internet. Chat room users talk to each other in Real Time (unlike E-mail) by typing or dictating messages that appear in sequence in the chat room window on each person's computer. Chat rooms are a form of Instant Messaging. Most chat room users use a "screen name" or pseudonym and often type using lots of shortcuts and Smileys. Chat rooms are much more "immediate" than SMS text messaging, and if you have unmetered Internet access then chat rooms are much cheaper too. Some chat room systems, such as "Habbo Hotel", are like virtual worlds, full of Avatars interacting in a complex, Real-Time environment See also ICQ, IRC and MSN Messenger |
| CLEO | Cumbria & Lancashire Education Online - The organisation given the task of providing Cumbria and Lancashire schools with Broadband access to the Internet, among other things. See www.cleo.net.uk for more information. |
| Client | Posh name for a customer or patient, a consumer of services. Computer clients are the opposite of Servers - they use the Network facilities provided by servers. Normally there will be many more clients than servers. As with servers, it is the Software rather than the Hardware which determines a computer's rôle. |
| Client/Server | A computer system in which part of the processing is performed by the Client and part by the Server. The World Wide Web is a Client/Server system: the Browser is the client and the Web Server is the server. Alternatives to client/server are "centralised", e.g. the mainframes and "green screen" terminals of the 70's and 80's, and "Peer-to-Peer" where each computer "peer" performs the same activities. |
| Codec | Contraction of Coder/Decoder - A term found mainly in the realm of computerised audio and video ("Multimedia"). A codec is a piece of Software that converts data from one format to another. For example, there are millions of audio files on the Internet in a format called "MP3". In order to hear these on your computer you need an audio player (such as WinAmp or Windows Media Player) that has an MP3 codec. Codecs are often found in the form of Plug-Ins, which allows new formats to be added to an existing player or recorder's capabilities. Many file formats (including MP3) are proprietary (patented), and some proprietors charge hefty royalties or licensing fees. An unwelcome trend (for most people) is the increasing use of codecs that include "Digital Rights Management" (DRM), e.g Microsoft's ASF and WMA formats (but not MP3). This is probably why there are so many different formats that seem to do the same thing. |
| Compression | Squashing files so that they take up less space and/or take less time to transfer from one place to another. Files that are intended to be transferred using the Internet (apart from graphics) are usually compressed in a format called "Zip", which means that unless you are using Windows XP, you need a program such as WinZip to expand files back to their original state. Some file formats, particularly graphics formats such as GIF, JPG and PNG, already include compression. |
| Contention | A DSL term, usually expressed as a ratio (e.g. "50:1"), referring to the standard practice of "oversubscribing" or sharing DSL Internet connections. A typical 50:1 contention ratio for your home 512Kbs Broadband connection means that you are actually sharing the 512Kbs Bandwidth with up to 50 other people. In the worst case your connection bandwidth (speed) will be only one fiftieth of the rated speed, i.e. 10Kbs (note that the standard dial-up bandwidth is 56Kbs). ISPs get away with this because most of the time most people will not notice. This is because most people use their Internet connection very erratically so at any given instant it is unlikely that many of the 50 people are using much of the shared bandwidth, and the ISP can also "spread the risk" like insurers do by sharing, say, 100 lines-worth amongst 5000 people. DSL lines with lower contention ratios cost a bit more; 20:1 is common for more up-market packages. The contention ratio is normally quoted in the ISP's advertising. |
| Copper | Jargon for "wire cables", normally in the context of Network cabling. Used to distinguish between electrical wiring and fibre-optic cabling. For example "gigabit over copper" means Gigabit Ethernet using cheap, short-distance Category 5e cabling rather than expensive, long-distance fibre optic cabling. |
| Cookie | Big Brother is watching you: cookies are one of the means by which Web sites and advertisers attempt to recognise you and track your browsing actions. Cookies are small identifying files that a Web Server sends to your Browser. They can be persistent or non-persistent. Non-persistent cookies such as session cookies are harmless, because your browser throws them away at the end of a "session". They are typically used to keep track of your identity during a purchasing transaction, maintaining the integrity of the transaction. Persistent cookies are actually stored on your computer for future use, so that Web sites recognise you as a previous visitor. This can be a good thing, if you want the Web site to recognise you and thereby "enhance your browsing experience". Or it can be a bad thing, if you didn't know you were being tracked and it isn't actually the Web site you visited that is tracking you, but the company with an advert on that site and on 200,000 other sites, and which is building up a profile of your movements (typically using "third party" cookies) in the hope that sooner or later you will click on one of its adverts or enter your E-mail Address into a form, at which point is has a very valuable marketing asset. So most browsers have a setting that allows you to have some control over cookies, at least allowing you to block persistent cookies. Note that by Default, your browser will normally accept ALL cookies and will not tell you that it is doing so - it is up to you to tell it not to. See also our Site Policies, Adware, Web Bug. |
| COPPA | Children's Online Privacy Protection Act of 1998 - A US law that attempts to prohibit the collection and dissemination via the Internet of personal information relating to children under the age of 13. There is no similar UK law, but the UK Government has published rather low-key guidelines for schools on the use of pictures and details of children on their Web sites. Many schools currently flout even these guidelines. |
| Cracking | Has various meanings, one of which is the activity of "Crackers" - not very nice people whose aim in life is to prove how clever they are at getting into other people's computers illicitly. |
| Crash | Computer-speak for "catastrophic failure". How big the catastrophe is depends on how long it is since you saved or backed-up the file(s) affected by the crash. If it is your hard disk that crashed, it could be a major catastrophe, whereas if it is just your Browser that crashes, it is unlikely to affect you much. |
| CSS | Cascading Style Sheets - An Internet standard for Web Page formatting, supported in some form by most Browsers since 1998. CSS is destined to become the primary formatting standard, replacing the old, messy, HTML "layout tables" and "format-as-you-go" approaches. There are 2 major advantages to CSS: firstly it is easier to maintain visual consistency across all the pages in a site and for all Browsers, and secondly in non-CSS browsers (such as screen readers for blind people) CSS pages will tend to be much more readable than Frame and table-based pages. Fully CSS-based Web design is usually used in combination with XHTML, because the people who recognise the advantages of the one generally also see the advantages of the other. CSS Level 1 (CSS1) was the first version and covered mainly text styling, the current version is CSS2 which includes sophisticated layout facilities. Unfortunately as yet, no browser accurately interprets every detail of CSS2, but generally they display pages more consistently than if the pages were written without CSS. This site uses CSS for both styling and layout. See also W3C. |