Zip it!

Zip Files

Zip files have been around for decades.  A zip file is compressed data from another file in order to make its transfer faster or to allow for greater storage on a hard drive.

Purpose of Zip

Basically, Zip takes a file and uses a formula to convert all of the words and phrases (or code) in the file into smaller codes that use less characters.  Then, later when you "unzip" in translates those codes back into the original text.  There are other compression formats as well, such as RAR, ARJ, or ARC that work similarly. Zip seems to be the most popular by far, not only because it works well, but because it is in the public domain and free to use.

Zip files are not as important as they used to be.  Many formats already use compression, so zipping them does not do much more.  Compressing a text file may make it as little as 1/10th its former size.  But zipping a JPEG photo, which already uses compression, gets you almost no space savings.  Most people don't bother to zip files any more since they are usually small enough and the Internet fast enough that it would take more time to zip/unzip than it would simply to transfer the file as is.

Gmail and Zip

Google still likes the Zip format.  If you download multiple mail attachments at once, Gmail puts them into a Zip file.  If you want to avoid this, you can download the files one at a time.

Zip/Unzip Programs

For many years, you needed a special Zip program to zip and unzip files.  The original program made for this purpose was called PKZIP, using the initials of the creator of the Zip format: Phil Katz.  But many other programs have evolved to support Zip.  One of the most popular is WinZip, although I don't like that one, as it is shareware.  After 30 days you have to pay to continue using it.  I like a free program called 7-zip.  It has an easy to use interface, supports multiple compression formats and works well with all versions of Windows.  There are also dozens of other programs that do pretty much the same thing.

Unzip Without a Program

For the main function most people need, unzipping a zip file, you probably do not need a special program at all.  Microsoft long ago incorporated an unzip feature directly into Windows.  If you have a zip file on your computer, you just double click on it and it should open.  You can see all the files or folders stored in there.  You can click on any one of them to access it.

Extracting Zipped Files

There is an important caveat however.  When you are viewing the contents of a zip file, you can only open one file at a time.  If you click on a program that relies on other files within the zip file, it will not work.  For that, you will need to extract the files.  If you have double clicked on a zip file and see the contents, in Windows XP click on the tool bar and go to File, Extract All.  In Windows 7, you see "extract all" directly on the tool bar.  This opens an extraction wizard that will let you save all the files uncompressed to a folder of your choosing.

Times to Use a Zip Program

Zip files can also be password protected. If you get one like this, you may not be able to open it in Windows.  In that case, you will need a program like 7-zip to open it.  If you get a compressed file in a format other than Zip, it is likely that 7-zip will also support that format.  If, for some reason you wanted to Zip a file, you would also need the program.  Windows only supports unzipping.

No Relation to Zip Drives

In between the development of floppy disks and CD-R disks, there was a disk sold called a "zip disk," which stored about 100 MB of data on a disk.  They never became terribly popular since they were from a proprietary system that required special hardware to run.  They also had an unacceptably high failure rate Despite the similarity in name, they are of no relation to zip files.  . If you get a Zip disk from someone, we cannot help you with it unless you have a zip drive to open it, and that drive is able work with a modern version of Windows.