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[ The PC Guide | Systems and Components Reference Guide | Hard Disk Drives | Hard Disk Logical Structures and File Systems | Disk Compression ]

File Compression Products

Over the last several years, volume compression has taken a nose-dive in popularity. At the same time, however, file-based compression has increased in popularity dramatically. The reason that these two technologies have "passed in the night" is simple: the last five years have seen hard disks dramatically drop in terms of price per megabyte, making volume compression much less important. The same time period, however, has seen the rise of file-sharing and distribution using both conventional media and the Internet. File-based compression is an essential component in the easy transmission of files over the Internet, because it allows blocks of files to be both packaged into a single unit, and to be sent more quickly over relatively slow networking technologies, like analog modem dial-up.

There are many different file compression technologies in existence, each of which compresses files in a slightly different way. And for each of these compression algorithms, there are many specific software products that can be used to compress or decompress. I'm not going to even attempt to delineate all the different products that exist, but will instead explain this software in general terms, focusing on what is most commonly used in the PC world.

The most popular family of compression products, by far, is the one based on the ZIP format, first widely implemented in the PKZIP and PKUNZIP shareware utilities created by PKWARE, Inc. If you have been using computers since the dark days of DOS, you probably recall using these two programs at one point or another. The ZIP format is, today, pretty much the standard for distributing files over the Internet; programs using this format usually have a ".ZIP" file extension.

With the rise of Windows, PKZIP and PKUNZIP have fallen out of favor, since they use that scary old DOS command line interface. :^) (I still use them, but then I like using old software. :^) ) As Windows has become popular, many Windows programs have entered the market that can let you zip or unzip files using a graphical interface. The most popular of these is probably WinZip, though there are literally dozens of products that can access the contents of ZIP files now. While ZIP files are the ones you will most often encounter, you may occasionally run into other compressed files, using formats such as ARJ or RAR. Other compression formats may require the use of a special utility program, though many of the programs that can handle ZIP files can also read these alternative formats.

One final class of file compression product bears special mention. Some utilities are now on the market that integrate ZIP file support directly into the operating system. When such a utility is installed and activated, ZIP files are turned into special Windows folders, and the files within them can be accessed directly without requiring explicit decompression. You can even save files from an application to the interior of a ZIP file, or run a program from within a ZIP file! I use a utility called ZipMagic (originally produced by Mijenix, which was bought by OnTrack Data International a few years back) that gives me this functionality, and I consider it a life saver. I have it set up so that with a special keystroke I can change all my system's ZIP files into folders, and I can turn it off when I want them to be seen as regular ".ZIP" files again. You can also easily compress a regular folder (directory) by changing it into a compressed "ZIP folder". Very useful stuff, and the closest thing to NTFS's file compression that you can get under the consumer Windows versions.

By the end of the 1990s, ZIP file support was becoming pretty much a necessity. One of the first things most people who set up new systems would do is attempt to download an updated driver or other files, and find that they were packed into ZIP files. So, one of the most common "first installs" in a new PC was a program like WinZip. Recognizing this, Microsoft began to add ZIP file support to Windows. First, it was placed into the "Plus!" add-on for Windows 98. Later, it was incorporated directly into Windows ME. To enable this support you must install or enable the "Compressed Folders" feature within the operating system. Doing this will allow you to access the contents of ZIP files in a format similar to how the Windows Explorer shows regular files. I have not used this feature myself, but it appears to be similar to the way that utilities like ZipMagic function.

Note: There seems to be some dispute as to how closely this integrated product matches what ZipMagic does; some users have said that the Microsoft feature does allow ZIP files to be used like regular folders in a way that is the same as ZipMagic, while others have said that ZipMagic is more full-featured than Microsoft's "Compressed Folders". For their part, OnTrack maintains that ZipMagic provides several features that Microsoft never implemented, and therefore that ZipMagic is still a useful purchase under Windows ME. As usual, your mileage may vary; you should decide for yourself if what ME includes is good enough, based on your needs and wants. (Although it does seem clear that the advanced archive management facilities built into ZipMagic were not implemented by Microsoft.)

Next: Volume Compression Products


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