Getting Right Program Key To Unlocking Zip Files -- Internet Tips

For newcomers to the World Wide Web, the ZIP file is one of the great mysteries of life. Consider the reader who sent this e-mail query: "I tried to download a program with my Web browser and what I got was something called a ZIP file. When I clicked on it with my mouse I got this weird message and nothing happened. What did I do wrong?"

You just haven't taken the final step, which is turning the ZIP file into the program you want. And for that, you'll need some additional software - which you can also find on the Web. But first it helps to know exactly what a ZIP file is.

A ZIP file is a handy way to store information and squish it so that it takes up less space on your disk drive and less time to transfer.A ZIP file - technically, a "compressed archive" - usually contains many files, perhaps dozens or even hundreds.

Why would you want to combine so many files into one? Well, archiving makes it quicker and easier to transmit those files from one place to another. You also don't have to worry about losing anything.

This is a critical issue when you transfer software, because most programs are actually large collections of files, each of which has to be in the right place for the software to work. A ZIP file is also compressed, which means that it's a lot smaller than the sum of the files it contains. Compression is a big deal because it costs money to store information and send it over phone lines.

So how do you compress data? As it turns out, most of the information we create is repetitive. For example, this column contains repetitions of sequences of characters, such as the word "the." Digitized photos with large areas of the same color contain millions of identical dots.

This waste of space has tantalized mathematicians and programmers since the dawn of computing, and over the years they've developed software for compressing all kinds of information - sometimes by ratios of as much as 100 to 1. For computer programs and business data, you can expect ratios as high as 10 to 1.

Archives with the ubiquitous .ZIP extension are compressed according to a formula developed by Phil Katz, a talented programmer and marketer who developed compression software called PKZIP in the late 1980s.

It's not the best compression system ever developed, but over the years it has become a standard.

To use a ZIP file that you've downloaded, you'll need a program that can unpack it and extract the original files. But you might as well get one that can create ZIP files, too.

There are dozens of ZIP utility programs available on the Web. Luckily, you won't need an unZIPping program to use most of them because they'll install themselves automatically. The better programs also handle files compressed in formats used by Unix and Apple systems.

The most popular of the bunch is Nico Mak's WinZIP, a $29 shareware program which is available for downloading at http://www.winzip.com.

You might also consider the latest Windows version of Phil Katz's original at http://www.pkware.com. Also check out CNet's http://www.shareware.com or Ziff Davis' utility archive at http://www.zdnet.com.

I do my own ZIPping with Norton File Manager, which is part of Norton Navigator - a superb set of Windows 95 utilities that everyone should have. You can download a trial version at http://www.symantec.com.