Have you ever had a client ask what file format is represented by an EPS extension? What about J62, EXE, JPG, LTM, or HDF? Sure, you’re probably able to name several of these off the top of your head, and you can make an intelligent guess about some of the others. But some are less obvious, especially if they have more than one possible meaning. Now there’s an online resource to solve this dilemma. Whatis.com comes to the rescue not only with an exhaustive list of file extensions, but also much more.

TechRepublic originally reviewed Whatis.com in May 1999 (click here to read that article), but many new features make this site worth a second look. Whatis.com serves primarily as an online IT information bank, focusing on the Internet and computers. Visitors can search the site either by keyword or scrolling through the exhaustive list of IT terms and acronyms.

Navigating the site
The home page is conveniently organized into three frames—a navigation bar, an alphabetic list, and a results window. The navigation bar on the left provides trouble-free movement throughout the site while also having a Quick Search feature. The alphabetical list displays all available entries beginning with a specific letter or number. Red-letter links located at the top of this frame are also provided for easier exploration. Once you locate the desired term or acronym and click on it, the results window springs to life with your requested information.

Finding those file extensions
While all this may seem great, you may be wondering, “What about the file extensions?” Here’s how you find them. From the Whatis.com home page, click on the Every file format in the world link. This will open an alphabetic listing of 4,431 file formats, last updated on 6/15/00 (according to Whatis.com). This list is divided into five main sections: A through E, F through J, K through O, P through T, and U through Z with Numbers. You can also utilize the red-letter links at the top of the page for faster navigation. Extensions are listed with a brief but detailed description. If an extension has more than one possible meaning, each is referenced separately.

Final thoughts
Whatis.com may not be the ultimate online encyclopedia, but it’s a great reference tool. Whether you need the meaning of AGP or MCSE, or if you’re looking for that unfamiliar file format, this Web site can help. The next time someone asks you what an HDF file is, you can respond, “It’s either a Help file (Help development kit), a hierarchical data file, or a National Center for Supercomputing Applications Geospatial Hierarchical Data format file.”Just remember, this utility works only if your client hasn’t renamed the file extension. If they’ve just decided to use their initials as the extension, all bets are off.

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