Data compression is often used to:
- Prepare files for data backup (see library article What Are Data Backups?)
- Send large files as e-mail attachments
- Make files download faster from websites (Note: always run virus checking software on compressed files downloaded from
a website)
Files you might want to compress include images, mailing lists and large documents. Compression is crucial if you want to send a group of images or chapters of a document as
one attachment. Your recipient will be able to download the file quickly, decompress (or unzip) the file and access all of its individual documents. To do so, your recipient
will need decompression software, which usually may be downloaded for free form
the commercial program websites noted below.
There are several versions of compression and decompression utilities available. Compression utilities are sometimes referred to as zip programs. some are specifically designed for either Mac or PC files, but many
will work with both formats.
Common Extensions
An extension is the group of letters after the name of a file that tells your computer what
type of file it is.
You can recognize a compressed file as having the following extensions:
- .bin - Mac compression format
- .hqx - compression format often used by e-mail programs
- .sit - Stuffit, Mac compression format
- .zip - popular compression format, most programs will open
- .tar - tape archive
- .img - images
Freeware and Shareware
Many compression and decompression utilities are available as freeware or shareware:
- Freeware includes software programs that can be downloaded for free from the Internet;
freeware can be equal in quality to commercial products, however technical support
is rarely provided.
- Shareware is similar to freeware but requires a modest payment, or at least registration
with product designer, for use of all features.
Follow these directions to visit CNET.com for brief descriptions and user ratings, in addition to links for freeware and shareware products.
Enter http://download.com into your browser window. Select downloads for Mac or PC (or others, if applicable), and then select Utilities to open new page. Select File Compression to open another new page with a list of downloads.
Or enter this URL directly:
http://www.download.com/3150-2250-0-1-1.html?legacy=cnet
Commercial Products
The following is a list of popular commercial compression and decompression utilities
(a utility is a software program designed to carry out one specific function.)
Keep Your Software Updated
Periodically check for upgrades to your compression/decompression software. Software
developers will often post free upgrades on their websites, or you can search
the web by typing the name of your software and the word upgrade. By having the latest upgrades you will be able to compress and decompress most
files with little difficulty.
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