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When less is moreÉ

If you transfer files across a network or over a modem, you might be using a compression program such as StuffIt, CompactPro, or DiskDoubler. Compressing and/or combining files to be transferred can save you timeÑand money, since the information services charge for your time online. Be careful not to make a common mistake when using file compression. Generally, files under about 25Ð30K require so little time for transfer that file compression is not worth the bother. Some programs, such as StuffIt Deluxe, will semi-automatically (with a simple click or two) compress a file on your end of a network and automatically expand it when it reach its destination. DiskDoubler is another good choice for networks because files compressed with it open with a double-click and are automatically recompressed when you quit their application.
<Body text>Another common mistake is to create self-extracting archivesÑthose files youÕve seen that have the suffix Ò.seaÓÑwhen you shouldnÕt do so. A self-extracting archive lets the user decompress, i.e., extract, the compressed file(s) by double-clicking on it. It is not necessary to have the original compression program, or a special extraction program, to expand the file. A self-extracting archive is best when you have a relatively large original file, greater than about 50K, or multiple combined files, to send to people that do not have a means to extract the file otherwise. However, the code that creates the self-extraction part of the archive adds about 15Ð20K to the size of the file. Because most files compress to only one-third to one-half of their original size, it is rarely helpful to make a self-extracting file from an original that is smaller than approximately 30Ð50K. For example, creating a self-extracting archive from a 10K file gives you a ÒcompressedÓ archive of about 20KÑi.e., twice the size of the original file. Experiment with your compression program and see for yourself.
ÑTom Pitts, MacValley Voice, newsletter of the MacValley Users Group, Burbank, CA
