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SOMETIME in your computer experience you’ll find yourself looking at a "ZIP" file, or maybe just looking to save some disk space or speed up file transfer. What I’m going to talk about this month is this issue of "zipping," or compressing, files and them "unzipping," or decompressing, them. Although the price of disk space
is cheap, there never seems to be enough. More serious problem's
lie in the slow transfer speeds of our 28.8 and 56k modems, especially
when transferring large files, and in trying to transfer files
between different types of computers, such as Windows,
The resulting file is not always smaller, or even significantly reduced in size. This may be caused by the type of file you’re trying to compress. It may already be compacted, for instance. Still, it never hurts to compress a huge file before you e-mail it to a friend so it will transfer and download faster or do it just to save some space on your hard disk (you can leave the file "archived" until you need it). To decompress a file, you simply
run your compression program and "extract" the file
from the
Another great feature of compression programs is their ability to create a compressed file that is "UUEncoded." This means the file is composed of standard text characters so it will transfer over the Internet and allow other types of computers to read it more easily. ZIP files can contain more than one file, making it easy to send a large number of files over the Internet simultaneously. This frequently saves me a lot of time because the collection of files is packed as a single one that is usually a lot smaller than the original s when it is compressed. Macintosh users have their own special compression program called StuffIt. Stuffit was created to compress files on the Macintosh, which has special needs for storing information about a file. It will also read and write ZIP files, so you can use it transfer images and text with your PC friends. Here is a partial list of companies that make compression software:
All of the programs listed above allow for a free trial period, so you can download and try them before buying them. I’ve used all of the programs listed above, and each has it’s own special features. I typically use ZIP programs several times a week, for both compressing and decompressing files. Well, that’s it for this month. I’m writing this from my hotel room at Comdex in Las Vegas. Comdex is the second-largest computer show in the world, bringing in about 250,000 people for the week-long event. If you visit our Web site at http://www.dacs.org, you’ll find my exclusively online coverage of the event. Next Month: In-depth coverage of several compression programs, including PKZIP, WinZip, ZipMagic, StuffIt, and more. |
| MIKE is a founder of DeMorgan Industries Corp., the leading developer of Web graphics, and also teaches Webmaster and Internet marketing classes at the Internet School in Naugatuck Valley Community Technology College. You can reach Mike at: mikek@demorgan.com |
These problems, and many
more, were solved in the late 1980s when a small company called
PKWare created the ZIP file format. Their program, PKZIP, used
a new format that was published as an open specification. Although
it wasn’t the first program of its type, it shortly became
a standard that any developer could use to write a compression
program. This solved the issue of creating one format that everyone
could use, regardless of platform. ZIP compression and decompression
programs are found on almost every type of computer, including
Amiga, 
Some compression
programs allow you to encrypt your data as you compress it, so
you don’t have to worry about someone intercepting your
file while you’re sending it over the Internet or reading
it on your hard disk while you’re not there.