Here is a collection of words and definitions provided by the Doctors of Technology to help you understand and learn more about your computer and technology. Bookmark this page or send it to a friend!

404 error: An error message received when you try to access a web page that either doesn’t exist or is unavailable at the address you gave.

ActiveX: A Windows technology which allows programmers to do various things on your computer. Unfortunately it also allows hackers to do bad things to your computer, particularly via webpage’s in Internet Explorer, and is safest switched off. (In Internet Explorer go to Tools/Internet Options/Security and set the Security Zone slider for Internet to High. A few websites won’t display quite as intended without it, but most bad ones won’t be able to hijack you).

AMD: AMD is a leading manufacturer of processor chips for PCs, including the Athlon and Duron chips.

Antivirus: Software which protects computers from viruses and suchlike. Has to be updated frequently to keep up with the latest threats, so is usually sold with a subscription which enables you to download updates from the internet.

Application: Software used to carry out a particular task, such as word processing or desktop publishing. Essentially another word for program.

Athlon: A PC processor – AMD, the other leading chip manufacturer’s equivalent to Intel’s Pentium. Like the Pentium, constantly being upgraded. You will often see a number such as 2700 following the word Athlon, which is a rough measure of the processor’s speed – the higher the number, the faster the chip.

Backup, back up: A backup is an extra copy of your work, eg documents, pictures etc, saved onto a removable storage medium such as CD, DVD or magnetic tape, so that if your computer is stolen or breaks down you don’t lose everything. Backup is a noun, back up is a verb.

Bandwidth: A measure of total amount of data transferred over a period of time, often used to measure how busy a website is. A webhost will usually base its charges on the bandwidth a website uses, ie how much data per month is requested from it.

Broadband: Internet access over a connection much faster than an ordinary modem, such as ADSL or cable.

Cache: A temporary storage area for frequently or recently used data, either in memory, on your hard disk or the internet. For example, if you go back to a webpage you have recently visited, your PC will usually be able to display it from the internet cache on your hard disk, so it won’t need to download it from the internet again.

CD-ROM, CD-R: (Compact Disk-Read Only Memory) A misnomer, as strictly speaking it is not memory but storage. Identical to standard music CDs. Currently the most popular medium for releasing programs on, as it can hold literally hundreds of times as much information as a standard floppy disk, about 650 Megabytes in total. Once a CD-ROM has been created its contents cannot be changed. Now starting to be replaced by DVD.

Celeron: A PC processor – Intel’s budget chip, cheaper than the Pentium, but also less powerful.

CMOS: (Complementary Metal Oxide Semiconductor; pr. “see-moss”) A special type of memory which retains its data when the PC is switched off, used to store settings for things like what type of hard disk you have, and how much memory. The settings are accessed via the BIOS.

Cookie: A small data file stored on your computer by a website, in theory to allow it to “remember” your preferences, but in practice mostly used to track which adverts you have seen. You can set most browsers to reject all cookies, or to ask your permission before storing them, but this can generate multiple error messages on some websites and is generally more hassle than it’s worth – they are pretty harmless.

CPU: (Central Processing Unit) The nerve centre of the computer: everything flows through it. Often just called “the processor”. The best known PC processors are Intel’s Pentium and AMD’s Athlon.

Database: A program used for organizing any kind of information on a computer into a searchable form, anything from a list of contacts to a complex stock control and accounts system.

Domain: An internet address owned by a company, organization or individual.

DOS: (Disk Operating System; pr. “doss”) Usually refers to MS-DOS, which was the standard operating system for PCs until Windows 95 came out, now pretty much obsolete. Controlled by typing in text commands and has several serious limitations, but requires a much less powerful computer than Windows 95.

DVD: (Digital Versatile Disk Rewriter) A DVD drive that can create (“write”) rewriteable DVDs. There are several competing formats at the moment, but most recent drives support more than one format. It is likely that one of these formats will become standard in time, but at the moment it is not clear which. To add to the confusion, they tend to have very similar names: for example DVD+RW and DVD-RW are completely different formats, and incompatible with each other.

Encrypt, encryption: Coding data so that it can’t be read by hackers etc when transmitted over the internet. For example, any reputable website selling goods by credit card will encrypt your credit card number and personal details.

exe (or .exe): (EXEcutable; pr. “exie”, “dot exie” ) A file which is usually the main part of a program. A program may consist of just an exe file and nothing else, or there may be dozens of files, including more exes.

Firewall: Originally a dedicated computer between you and the internet, preventing hackers, spammers and similar undesirables from taking over your PC. Now often just a program running on your PC, performing the same task. Absolutely essential if you have an always-on internet connection such as ADSL or cable.

Gigabyte (or Gig): Unit of measurement for pieces of information: approximately 1 billion bytes, 1 million kilobytes, or 1000 megabytes. Hard disk sizes are usually measured in gigabytes. Often shortened to “GB”, “Gig” or just G.

Hub: A basic device for connecting computers together to form a network.

IDE: (Integrated Drive Electronics ) A type of PC hard disk, now obsolete.

IP address: (Internet Protocol address) A unique number assigned to any computer connected to the internet, including yours, in the format 255.255.255.255. Each of the four blocks of numbers can be any value from 0 to 255. They can either be assigned permanently (“static IP”) or per session (“dynamic IP”). Most ISPs assign them dynamically, ie when you connect to the internet.

Malware: A catch-all term for software installed by stealth onto a PC for malevolent purposes (hence the name). These may include displaying unwanted ads (adware), installing software you didn’t ask for, or spying on your activities (spyware) and reporting them back to the culprit so that he can steal your bank account, address book etc.

Network: A way of linking several computers together so that their users can share resources such as printers and documents, often via a central computer called a server. See also LAN, WAN, Ethernet.

OEM: (Original Equipment Manufacturer) A company that actually builds computers, as opposed to just retailing them. “OEM software” is ordinary software bought in bulk at a discount by the OEM and pre-installed on new machines, usually without printed manuals. OEM software cannot legally be sold separately from a computer, so when offered for sale at huge discounts is either pirated, or not what it claims to be.

Operating System: Every computer has an operating system, which is a sort of master program that runs automatically when you switch the computer on, and continues running till you switch off. It is responsible for the many routine tasks required to keep a computer running: moving the pointer when you move the mouse, providing icons and menus, running other programs such as a word processor or a game which you may request, controlling the various disk drives, the screen and so on. The most widely used PC operating system is Microsoft Windows.

Parallel Port: A special socket for plugging a printer into a computer. The computer usually refers to the parallel port as LPT1.

PCI: (Peripheral Component Interconnect) A standard for PC expansion cards, currently the most popular. A “PCI slot” is a socket on the motherboard for such cards.

POP3: (Post Office Protocol version 3; pr. “pop 3″) A protocol for transmitting and receiving email, but mostly used just for receiving. (Transmitting is still mostly handled by its less powerful predecessor, SMTP).

Processor: The nerve centre of the computer: everything flows through it. Also called the CPU. The best known are Intel’s Pentium and AMD’s Athlon. The most important single specification on any PC is the speed of its processor, usually measured in megahertz (MHz), or gigahertz (GHz).

RAID: (Redundant Array of Inexpensive Disks; pr. “raid”) A way of connecting multiple hard disks together so that a computer sees them as one very large, very fast disk instead of many smaller ones. Often called a “RAID array”, even though the acronym already contains the word array. Mostly used on network servers.

Registry: A file on Windows PCs which contains all the settings for the PC and its software. Can be edited by the user, but this should only be done as absolutely a last resort, as it is possible to trash the operating system completely if you don’t know what you are doing.

SATA: (Serial Advanced Technology Attachment) The latest high speed standard for connecting hard disks to your computer, replacing EIDE on most new computers.

Spam: Originally a name for mass postings to Usenet newsgroups advertising products or services, regardless of their relevance to the newsgroup. (The name comes from a famous Monty Python sketch in which every conversation is interrupted every few seconds by people shouting “spam spam spam” at the top of their voices). Now generally used to describe bulk commercial advertising emails (UCE). Sending spam is a violation of most ISPs’ AUP.

Spyware: Programs, typically installed by stealth, which record what you do on your PC and send reports to criminals, allowing them to steal your bank details, passwords and so on. See also Malware.

Terabyte: Unit of measurement for pieces of information: approximately 1 trillion bytes, 1 billion kilobytes, 1 million megabytes or 1000 gigabytes. That’s a lot of data.

Trojan: A program similar to a virus which is disguised as something harmless like a game, but when launched actually sabotages the computer on which it is running.

URL: (Universal Resource Locator) an address used to locate something on the internet, most often a web page. All web addresses are URLs.

Virus: A program that has been deliberately created to cause computer problems, usually minor ones as a prank, but occasionally very nasty ones indeed, such as erasing your entire hard disk. Viruses were originally designed to attach themselves to programs on a disk, and then “hide” in the computer’s memory once the host program is executed, and “infect” every disk they come across. Some types of virus (such as the famous “I love you”) propagate by email, disguised as an attachment, which is why you should never open an attachment you are unsure of.

WAN: (Wide Area Network) a sort of group of networks, or more properly LANs, connected together.

Wi-Fi: (Wireless Fidelity) A method of connecting computers together in a network without cables, using small transmitter/receivers connected to ordinary PCs, printers, broadband modems etc. See 80211 etc.

Zip drive: A special drive for removable data cartridges often used for making backups as the cartridges can hold a lot more data than a floppy disk. Now pretty much obsolete, as almost all PCs have CD or DVD writers fitted as standard.