John Cletheroe's
PC And Internet Hints

PC And Internet Glossary - Including File Extensions - A

AA

Anti-Aliasing. See that entry.

AAC

File extension. Advanced Audio Coding. The audio file format used by the Apple iPod and iTunes system.

Abstraction

A term used in object oriented programming. I have yet to find a meaningful explanation of the term.

ACC:

Microsoft KnowledgeBase article title prefix for articles relating to the Microsoft Access database system.

ACE

An archive file format, similar to ZIP. The contents of ACE archive files can be extracted using the "Unzip Them All" utility, which is available via http://www.bykeyword.com or downloaded directly from http://www.herve-thouzard.com/unzinst.exe (both external links verified Jun-04). Alternatively, use the WinAce program, which can be downloaded from http://www.winace.com (external link verified Aug-04).

ACL

Access Control List. A feature of some operating systems, whereby access to devices, folders and files can be controlled. Each category of user (the file's owner, other users in the same group as the file's owner, other users on the same computer, users accessing the file via a network, etc) can be given permission to read a particular file, modify it, delete it, etc. Access Control Lists are powerful and flexible security mechanisms but very complicated to understand and extremely time-consuming and tedious to maintain. The old DEC VMS operating system had Access Control Lists and I believe that Windows XP has them if disks are formatted using NTFS (but this may only apply in the Professional Edition).
Application Compatibility List. Same as Software Compatibility List (SCL) - see that entry.

ACPI

Advanced Configuration and Power Interface. One of several standards for power management for Intel/Windows computers. See also APM.

ACT

Application Compatibility Toolkit, a component of Windows XP which may enable programs written for older versions of Windows to be run.

ActionScript

The programming language for Adobe Macromedia Flash applications.

Active

The only descriptions of this term that I have managed to find have been written in Microsoft's meaningless management/marketing language, which has virtually no information content. I doubt if the word actually has a real meaning.

Active Desktop

See New Desktop.

Active Directory

See Directory [5].

Active Movie

A type of video file.

Active Server Page

See ASP [1].

ActiveX

According to Network News 16-Jun-99: "ActiveX is the marketing name for a set of technologies and services, all based on the Common Object Model (COM) [other sources say Component Object Model]. In essence, it is Microsoft's alternative to Java. But whereas Java has now moved beyond the web and into business applications, ActiveX is still very much web-focused within the Internet Explorer environment. In the past the Microsoft program technology for supporting compound documents was known as OLE (Object Linking and Embedding). Many Windows files exist with an extension of OCX, standing for Object Linking and Embedding Control. Microsoft now uses the term ActiveX control instead of OCX".

In version 6 of the Microsoft Visual BASIC programming language the term "ActiveX Control" is used for what in previous versions was called a "Custom Control", i.e. a type of object which can be added to a program, additional to those types of objects which are supplied as inherent parts of the language (command buttons, option boxes, etc). These additional control types are loaded from OCX files; a single OCX file can contain one or more such controls.

See also ASP, which appears to be related closely to ActiveX Scripting.

ActiveX Control Pad

A program, available for downloading free of charge from Microsoft's web site.

Think of the name of this program as "ActiveX Control" "Pad", not "ActiveX" "Control Pad". In other words, this is not a control pad for ActiveX but an HTML editor, similar to the simple Notepad text editor.

Compared with the humble Notepad, ActiveX Control Pad has major enhancements which allow ActiveX controls to be added to web pages. This enables the creation of web pages which look and feel like Visual BASIC programs.

End-users viewing such web pages need to use Internet Explorer and have the relevant ActiveX controls installed on their computer. The ActiveX controls are not displayed in any other browser (I tried Mozilla, Netscape and Opera). In addition, a test page which I created and which worked correctly on my computer did not work at all on a friend's computer (quite possibly due to our lack of knowledge). Therefore this technique is probably inappropriate for the public Internet. It is, however, technically interesting.

I don't have a precise URL for the page to download ActiveX Control Pad from but a search for its name on Microsoft's web site should find it quickly.

Ad-Ware or Adware

Any program which as well as its main functions, also displays advertisements.

If this behaviour is clearly stated by the program's publisher prior to installation, restricted to times when the program is actually in use, and completely ceases when the program is uninstalled by normal means, then many users would regard it as an acceptable compromise in return for the program being made available free of charge. The Opera web browser program is a good example of such a program.

On the other hand, if this behaviour is not made obvious in advance (or perhaps at best only mentioned in a clause hidden deep inside the licence agreement), occurs even when the program is not in use, and is deliberately made very difficult to uninstall, then most users would regard it as being unacceptable. Some versions of some peer-to-peer file sharing programs suffer from this form of ad-ware.

In many cases, ad-ware programs are actually separate from a main program, but installed by the main program's installation procedure.

LavaSoft's excellent Ad-Aware program will detect the presence of ad-ware on a computer. Unfortunately the URL for LavaSoft's web site frequently changes but any search on the Internet should find a current source of their program.

Adaptec

A publisher of CD burning software. Adaptec were taken over by Roxio, who in turn have been taken over by Sonic.

Address Book

A file containing a list of email addresses, normally of people to whom you frequently send messages. The file is maintained by and used by an email program. Also called "Contacts".

ADE

File extension. Microsoft Access project extension.

ADF

Automatic document feeder. A sheet feeder for a scanner.

Administration, Administrator

In Windows XP, an administrator is a user with the highest level of privileges, with full access to all files, folders, programs and configuration settings.
A network administrator is a person in charge of the day-to-day running of a local area network. Network operator would be a more accurate title but it doesn't sound so grand.
The terms "administrator installation" and "administration installation" refer to the installing of programs from a server, via a local area network, within an organisation. In theory only the copy on the server needs to be kept up-to-date with patches. In some cases programs may not actually be installed on users' computers, but loaded from the server over the network as required. Over a slow network with slow computers this is a disaster for users.
The downloading, saving and installing of patches manually, as opposed to the automatic system used by Windows Update and Office Update, where the patch distribution files are not retained after being installed.

ADO

ActiveX Data Objects. Associated with Microsoft Data Access Components (MDAC), Distributed Component Object Model (DCOM) and OLE DB. Microsoft KnowledgeBase article 190463 has some information on this and related subjects.

ADODC

ActiveX Data Object Data Control (probably). A custom control (ActiveX control) which can added to Visual BASIC programs.

ADP

File extension. Microsoft Access Project. May only apply in recent versions of Access. I do not know whether ADP files can contain viruses or not.

ADSL

Asynchronous Digital Subscriber Line. A form of data transmission which provides high speed digital communication over traditional telephone cables. ADSL is one form of DSL (Digital Subscriber Line) and the various forms of DSL are types of broadband connections. However, the terms "ADSL" and "broadband" are increasingly being treated as equivalent.

Adventure Game

A type of computer game involving puzzle solving, usually in a fantasy, science fiction or detective fiction scenario. Early examples were text only, with no graphics. Later examples were controlled by text input but had illustrations. Modern examples are entirely graphical and are controlled by the mouse. There is usually little or no fighting or other real-time element to the game. The Zork series, Myst and Riven are famous examples of adventure games; there are a huge number of others.

Adware

See "Ad-Ware".

AF

Anisotropic Filtering. See that entry.

AGEIA PhysX

A physics calculations co-processor hardware add-on. A few programs, including the Kuju/EA Rail Simulator program (KRS) use this device if it is present in a computer. I believe that they automatically uses the main processor to perform the same calculations if it is not present.

AGP

Accelerated Graphics Port or Advanced Graphic Port. An expansion socket in many modern PC's for suitable graphics boards, which offers better graphics performance than a normal ISA or PCI expansion socket. Beside one AGP expansion socket, a PC will also have several ISA and/or PCI expansion sockets. Very modern computers might have a PCI Express video board socket instead of an AGP one, in which case an appropriate type of video board must be used with it.

Aggregator

A client RSS program (see RSS). Also called a news aggregator or a feed reader.

AI

Artificial intelligence.

AIF

File extension. According to one source, a type of Apple QuickTime video file. I do not know whether AIF files can contain viruses or not; it seems unlikely.

AIFC

File extension. According to one source, a type of Apple QuickTime video file. I do not know whether AIFC files can contain viruses or not; it seems unlikely.

AIFF

File extension. According to one source, a type of Apple QuickTime video file. I do not know whether AIFF files can contain viruses or not; it seems unlikely.

AIM

America Online Instant Messenger. AOL's Internet Relay Chat (IRC) program.

AIO

All-In-One. A combined printer and scanner.

AJAX

Asynchronous JavaScript and XML. A system which allows scripts in web browsers to access servers in the background without user involvement.

Alias

See Anti-Aliasing.

All The Web

A well known search engine. Also called FAST.

http://alltheweb.com

All Your Base Are Belong To Us

A classic example of a mis-translation from Japanese to English in an early video game. Now often used in a humorous or semi-humorous way to refer to a total victory, a monopoly, a complete dominance of one group over another, etc.

Allocation Unit

See Cluster.

Alpha

A very early version of a program, for testing within the company only.
A type of microprocessor which used to be made by Compaq (previously DEC, Digital Equipment Corporation). May no longer be in production.

Alpha Channel

A term associated with graphics. I think it specifies an object's opacity/transparency.

ALR

File extension. Adrift text adventure language resource file. I do not know whether ALR files can contain viruses or not, but it seems unlikely.

ALT

A key on the keyboard which can be used as a prefix, often to invoke a program's menu, or alternatively in combination with other keys to modify their effect.

Alta Vista

A well-known search engine. Originally created by DEC (Digital Equipment) and sold as part of that company when it was taken over by Compaq. Now sold to another company, I believe.

http://www.altavista.com

ALX

File extension. HTML Layout File. Closely associated with ActiveX Control Pad (see that entry). Since ALX files can contain VBScript programs, they could include viruses, although in theory browsers should prevent such programs from performing inappropriate actions.

Amnesi

A domain name search engine which allows you to look for the web sites of companies and other organisations. Requires your web browser to have JavaScript capabilities.

http://www.amnesi.com

Ampersand

& (see that entry).

ANIM

File extension. See this entry on my Trainz Wordz page.

Anisotropic Filtering (AF)

A term used in computer graphics. Anisotropic filtering is a method of improving the image quality of distant objects. It works by averaging the colours of adjacent pixels, deliberately blurring them so as to make them appear to merge smoothly. The process requires considerable processing power. I can't resist pointing out that it's a very impressive phrase to include in a product's list of features, even if very few customers will ever have the faintest idea what it means.

ANS

Advanced Networking Services, an Intel software component.

ANSI

American National Standards Institute. The standard for character encoding on computers. ANSI covers character codes from 0 to 255.

Anti-Aliasing (AA)

Attempting to remove the jagged edges of nearly horizontal or vertical edges displayed on a monitor, usually by means of fading individual pixels.

API

Application Program Interface. An operating system call under Windows.

Operating systems provide a means for users to perform everyday operations such as starting programs, copying and deleting files and so on. However, they also contain a large number of subroutines to perform common operations, available to any program which wishes to make use of them. Operating system calls (or API's, as Microsoft refers to them) are calls made to such subroutines by programs. Examples of operations performed by operating system calls are: open a file, clear the screen, and read a character from the keyboard.

Microsoft make available a huge text file which lists the format of the API functions. However, this does not contain any information whatsoever on how to actually use the functions in programming languages. Some KnowledgeBase and TechNet articles provide some clues as to usage but in most cases you need to experiment to discover this information.

Most custom controls (ActiveX controls) internally use API calls to perform their functions.

APM

Advanced Power Management. One of several standards for power management for Intel/Windows computers. See also ACPI.

Apostrophe

The single quote character: ' .

APP

File extension. Visual FoxPro Application.

Applet

A small utility program, often supplied free with an operating system. For example, the Calculator and Calendar programs supplied with Windows, and also the small CPL files which handle each Control Panel option.
A Java or JavaScript (or similar) program associated with a web page.

Application

Compiled program (and associated files such as DLL's, if required).

ARP

Address Resolution Protocol.

ARQ

Automatic Repeat Request. When this protocol is in use, your modem will automatically request that any corrupted data be re-transmitted.

Artefact or Artifice

Any visible corruption of a graphical image, for example of a JPG image saved with too low a quality setting, or the jagged edges of a line which is nearly but not quite horizontal or vertical.

AS

File extension. ActionScript source file. ActionScript is the programming language for Adobe Macromedia Flash applications.

ASAX

File extension. A .NET global application class file.

ASCII

"Askey". American Standard Code for Information Interchange. The standard and now virtually universal method of representing characters as numbers in computers. Strictly speaking, ASCII only covers character codes from 0 to 127. See also ANSI and Unicode.

ASCII Text File

A file with no internal formatting other than carriage returns. Such files can be created, viewed and edited with the EDIT and NOTEPAD programs. They can also be viewed with the DOS TYPE command and copied directly to a printer. HTML files are ASCII text files with HTML tags.

ASCX

File extension. A .NET mobile web user control.
File extension. A .NET web user control.

ASD

Automatic Skip Driver Agent. A feature of some versions of Windows (for example, Windows 98) which automatically disables drivers which fail to operate correctly when Windows starts up.
File extension. Microsoft Word AutoRecover file. Microsoft KnowledgeBase article 10768 has more information. ASD files can presumably contain Word macros, and therefore presumably they could contain viruses.

ASF

File extension. One type of Windows media file (sound, image or video, presumably). I do not know whether ASF files can contain viruses or not.

ASMX

File extension. A .NET web service.

ASN.1

Abstract Syntax Notation One. A language in which computer standards are written and also, it seems, an internal component of some versions of Windows including Windows XP. For more information see Microsoft Security Bulletin MS04-007 and Microsoft KnowledgeBase articles 252648 and 828028.

ASP

File extension. Active Server Page. An HTML file created by a program which runs on the server, usually obtaining data from a database. I think the program might be written in a language such as Visual BASIC Script or JavaScript. I believe this is a system developed by Microsoft. As far as the user is concerned the result is almost identical to that of CGI or PHP. ASP files can contain JavaScript and Visual BASIC script programs which could include viruses.
The system which produces ASP web pages. I suspect that ActiveX Scripting is closely related to ASP.
Application Service Provider. An ASP makes programs available to be downloaded via the Internet from a server when they are required to be run. The programs are never stored on the user's PC. The user is charged depending on the length of time they use the program.
Opinion: Anyone who has tried using such a system over a LAN will know how appallingly slow and unreliable it is and will shudder with horror at the thought of doing the same thing over the Internet. This is a truly crazy idea.

ASP.NET

Closely associated with .NET. According to one description, it is yet another scripting language, similar to JavaScript, VBScript, etc.

ASPI

Advanced SCSI Programming Interface. A software component associated with CD writer drives, even when they are connected via an IDE interface (Adaptec Easy CD Creator installed a WNASPI.DLL file on my PC, which has an IDE interface CD writer drive).

ASPX

File extension. A .NET data form wizard.
File extension. A .NET mobile web form.
File extension. A .NET web form.

ASR

Automated System Recovery. A feature of Windows XP but by default not installed with the Home Edition.

Assembly

In current Microsoft jargon, an assembly holds Managed Code (the Intermediate Language [IL] coding that is created by Visual Basic .NET and C# .NET compilers), together with metadata that describes the classes, methods, and attributes (such as security requirements) of the code. The Intermediate Language coding is run by the .NET Framework Common Language Runtime (CLR). In simple cases, copying an assembly is all that is required to distribute a program.

Association

A connection between a file extension (file type) and a program, so that opening a file with that extension will cause the specified program to run and open the file automatically.

Asterisk

* (see that entry).

ASX

File extension. One type of Windows media file (sound, image or video, presumably). I do not know whether ASX files can contain viruses or not.

AT Command

A command sent from a PC to its modem, for example to make the modem dial a number, to hang up, or to change the modem's configuration. I think "AT" comes from "attention".

At sign

@ (see that entry).

ATL

Active Template Library. A Microsoft software component.

ATM

Adobe Type Manager - software for fonts, superseded by TrueType fonts.
Asynchronous Transfer Mode.
Automatic Teller Machine - a bank cash dispenser.
Automatic Transfer Mode. A high-speed communications/networking protocol.

Atom

An Internet protocol very similar to RSS (see that entry). As far as I know Atom is nowhere near as popular as RSS. I have never seen any mention of a normal web site offering an Atom feed.

Attachment

A file sent with an email message. Email messages cannot contain viruses but attachments can.

Attribute

Any property of an object, a file, etc. Examples include the "read only" attribute of a file and the bold property which can be applied to a section of text.

au

The Internet top-level domain for Australia.

AU

File extension. Audio (sound) file. Sounds played by Java applets are often held in the form of AU files but I do not know if the language is limited to this format. I do not know if AU files can contain viruses or not; it seems unlikely.

Auto-Correct

A feature of Word 97 which most users dislike intensely and therefore disable. Auto-correct automatically changes the text you type in to the program - an action with is both very disturbing and potentially extremely dangerous. To disable auto-correct, open a document in Word, then TOOLS > AUTO CORRECT. Work through each of the four tabs in turn, removing all the ticks. You don't need to delete all the entries in the auto correct table, which would be a very lengthy task. If you've noticed some very strange things happening in Word 97, auto-correct is the likely cause.

Be careful not to throw out the baby with the bath water here. The spelling checker in Word is an extremely valuable tool and I would highly recommend its use.

Automation

A word used by Microsoft with various meanings, including the use of macros and Visual BASIC For Applications coding in Microsoft Office programs such as Word and Excel. According to some Microsoft documentation, "Automation" was formerly called "OLE Automation". Some sources describe it as a means of driving one program from another, although the purpose of performing such an act seems highly mysterious.

AV

Anti-virus.
Audio-Video, for example an AVI, MOV or QuickTime file which includes both audio and video.

Avalon

The codename for the new graphical sub-system which Microsoft intends to include in Longhorn (the new version of Windows, currently under development). Avalon is in effect the next version of DirectX.

Avatar

In a 3D game, the visual representation of the player's character. In many cases the camera is by default located just behind the character, allowing a view of the rear of the avatar and the scene that lies ahead.
In a discussion forum, a small graphic chosen by the user and displayed alongside each of their posts. Such avatars can be any image and are only very rarely a photograph of the person.

AVI

File extension. Audio Video Interleave. A type of video file. AVI files cannot contain viruses.

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