While surfing the Internet, you will no doubt find text, graphics, audio and video files to download. Multimedia files can be very large, which means they move very slowly across the global network. Downloading these files may take hours, depending on the speed of your Internet connection.
To make efficient use of disk space and speed things up, most large files are compressed. File compression reduces the size of a file, reducing the time it takes to download.
Compression software uses complex mathematical equations to scan a file for repeating patterns in the data. It replaces the data with smaller codes that take up less room. For example, one way compression software works is to replace repeating text characters with a code that also notes the locations of those characters in the data. With a picture, it would find all of the red pieces, for example, and replace them with a code.
To view compressed files, you need a compatible decompression program that can read these codes and convert the data back to its original form.
Most of the files you encounter on the Web are either text, graphics, audio, or video files. Some may be compressed, others not. The most common compressed files are those with extensions such as .zip, .sit and .tar. These extensions represent popular compression formats for the PC, Macintosh, and UNIX. They may be single files or groups of files that have been bundled together into a single archive. An archive file can sometimes contain video or graphics files within it and often contains software programs with related documentation.
To decompress a .zip file you need an utility like WinZIP or PKUNZIP, which are available on the Internet. To unstuff a file with a .sit extension, you need a program called Stuffit Expander, a popular program for the Mac. Though PKZIP will not decompress files that have been "stuffed," there is a StuffIt Expander version for Windows. StuffIt Expander can also decompress other formats, including .zip
Files with a .sea or .exe extension are self-extracting files for the Macintosh and Windows. They don't require additional software to run. You simply click on the file to launch it.
TIP: Create a Download folder on your hard drive, download the compressed file into this empty folder and decompress it into the folder. This allows you to keep track of the files that come out of the compressed file. You never know how many files might be contained in a compressed file.
For more information about compression, read the Compression FAQ [Frequently Asked Questions] that is available online at http://www.faqs.org/faqs/compression-faq/.
To download decompression software, visit http://www.Shareware.com.
