21. 1ST File Format

A file ending in ".1ST" usually is named "READ.1ST" or "README.1ST". These files are normally located in archives such as ZIP or RAR files, or they may be located in an application's main directory.

If the above are true, usually the file is a text file that the application developer(s) believe you should read first before either unpacking the archive or running the application. Such files may contain release notes with important software updates, bug lists, software incompatibilities with various hardware products, etc.

To play it safe, if you wish to open ".1ST" files, use Notepad or another text editor. If the results are gibberish, then the file may have other purposes than those mentioned above.

22. ARC File Format

The ".ARC" file format is similar to the ZIP or RAR file formats in that they usually are archives containing various other files. Though not commonly used today, you may see older software or software packages for Unix machine compressed using this format.

Though very few utilities may exist on the Internet to create these archives (and using such utilities is not recommended as better archive formats are available), if you need to decompress ARC files, try the following (listed for informational purposes only):

* StuffIt - versions for Macintosh, Windows, Linux, and Solaris

* WinZip for Windows supports ARC but requires external software.

The history of the .ARC file format is an interesting one, involving lawsuits and the eventual creation of the ZIP file format.

NOTE that some software packages may use .files ending in ARC for their own means, thus those files may not actually be archives. This is true for virtually any file type, however.

23. BAT File Format

The ".BAT" file format is a MS-DOS or MS-Windows batch file. In layman's terms, a BAT file contains a series of instructions for the computer to perform, usually for computer or file maintenance.

Without going into too much detail, some common commands you may find inside BAT files include:

COPY - Copies a file, sometimes from one directory to another

CD - Changes focus to a new directory to perform file operations there

DIR - Displays the list of files in the current directory

MD - Creates a new directory

MOVE - Moves a file, usually from one directory to another

RENAME - Renames a file

Just as TXT files, you can open BAT files in Notepad or another text editor. However, make sure you open your text editor first, and THEN open the .BAT file from within that application. This is because double-clicking BAT files usually run their contents as commands.

Since batch files can perform many different tasks, they can either be very useful or malicious in nature. For this reason, be VERY CAREFUL when receiving batch files through e-mail, instant messenger, or other questionable sources.

24. ASC File Format

Files with an extension of ".ASC" are usually ASCII text files, similar to the TXT file format. For Windows, while double-clicking an "ASC" file does not normally open Notepad, these files can normally be viewed with such a tool.

25. DOC File Format

Files with an extension of ".DOC" are usually documents created from word processors, most notably WordPerfect or more-frequently Microsoft Word.

DOC files can contain text, images, photos, or any other type of information commonly found in word processing documents. While most are safe to open, unfortunately some malicious DOC files can contain macro viruses that can do damage to your machine. Luckily, you can increase macro virus protection by using anti-virus software or changing word processor settings, including in Microsoft Word 2003.

In rare instances, some people write plain-text files and save them as .DOC files.

26. MOV File Format

The MOV file extension normally represents a QuickTime multimedia file. QuickTime is a movie/video/multimedia format developed by Apple and is often used in websites, mostly for streaming audio or video.

Apple distributes the QuickTime Player, allowing Mac and Windows users to view QuickTime multimedia either inside or outside of their web browser. Though the QuickTime player is free, Apple does sell a professional version supporting full-screen video and other features.

27. DAT File Format

The DAT file extension refers to a data file created by an application or the operating system. This type of file can contain virtually anything, such as:

* Application help text, such as for a spreadsheet

* High score files for a game

* Software configuration options, such as the default font used in word processor documents

DAT files are application-specific. Normally only the application that created a specific DAT file can read the DAT file, unless the application developer has released information to the public on how to read such file. DAT files may be unreadable, yet opening them in a text editor might display some legible information.

28. FNT and FON File Formats

The FNT and FON file formats usually refer to older Windows raster and vector fonts. Unlike TrueType font files (.TTF extension) that can be resized to virtually any small or large size, the older FNT and FON files are limited to specific sizes. Also, they may not look exactly the same onscreen and on paper.

29. PL and PM File Formats

The PL file extension often refers to scripts of applications written in the Perl programming language. Perl scripts are used on many websites to handle interactive feautres such as search engines, polls and surveys, order purchasing, and more.

PL scripts are written in plain-text and as such can be viewed in text editors such as Windows Notepad. However, they may contain a fair share of slashes, apostrophes, quotes, and other symbols, making it even difficult for other Perl programmers to read a piece of code.

You may also notice files with the PM extension near other files with a PL extension. Files with a PM extension are called "Perl modules" and are usually components of a larger Perl application.

30. ANI File Format

The ANI file extension often refers to an animated Windows cursor. Depending on how you wish to configure your Windows machine, you can have a spinning hourglass whenever your computer is waiting for a task to be performed, a tapping hand whenever you move your cursor over a link in a webpage, or even something more outrageous such as a flying spaceship over your normal mouse pointer.