Quick Guide to File Compression
FAQs | Glossary Of Terms | How-To Articles
If you have owned your computer for a year or
more, you have probably run into the problem of
large files, and hard-drive space. The salesman's
promise, "You'll never use all the space
on this computer!", sounds more and more
like so much advertising. Once you actually start
to use the computer for more than just the occasional
game of solitaire, all of the programs, video
games, and assorted emails begin to stack up.
Before you know it you may start getting warning
messages like, "Hard-drive space is running
low. Do you want to clean up some files on your
computer?"
Or perhaps you've run into a situation where
you've spent hours working on a report containing
lots of graphics, and charts, and some spreadsheets.
You go to copy the report to a disk or send it
as an email attachment, only to find that it has
morphed into a 15 meg monster of a file.
The best way to combat these kinds of file space
problems is to utilize a simple compression program.
The function of a compression program is to take
large files and make them smaller without changing,
or losing any information in the file. It does
this by using a complex set of algorithms and
equations that take the bits of information in
the file, reduce the size, and then remember how
to put the files back together. Since a file is
made up of 1000's of bits of information it can
be reduced from 1000's down to 100's without losing
information because an algorithm can predict where
those other bits WILL go when the file is uncompressed
later.
Now of course, like everything in the computer
world, there are many different compression programs
out there to choose from. Even though each program
uses different algorithms for their compression,
they all compress files about the same. A typical
compression rate for a 100k Word document containing
all text is about 60%-90% of the original file
size. With this in mind, choosing your own favorite
compression utility is usually a matter of personal
taste, and ease of use.
One of the most common, and user-friendly programs
is called PKZIP. This program is freely available
from www.PKware.com. It's user interface combines
functionality, with ease of use by putting the
compression terminology into easy to understand
terms.
Another highly used compression utility is called
RAR. The RAR compression format is an extremely
good one for packing together large programs into
one very small file. One of the best features
about this particular program is it's ability
to take extremely large files, and spread them
out over several smaller files which can be stored
on individual floppy disks. This program is also
free to the public at www.RARsoft.com.
A third extremely popular shareware compressing
agent is called ARJ, and can be found at www.ARJsoft.com.
This program has all the same abilities as RAR,
and PKZIP, but just in a different format, and
file extension.
With the various compression utilities out there,
it's nice to have more than one around so that
you can open other people's files. You can only
unzip a file with a .zip extension using PKZIP.
A file with the .arj extension can only be opened
with ARJ, and the .rar extension consequently
can only be opened with the RAR program. Most
files on the internet come compressed in one of
these three above formats, and some sites even
have 3 differently compressed copies for you to
choose from all in the place.
The world of compression is an important one,
simply for the fact that it allows us a little
bit of control over the size of our computers,
and the time which we spend downloading one another's
files. So when those files come up that just seem
bigger than you can handle, pull out your favorite
compression program, and cut it down to size.
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