Thursday, March 1, 2007

What is a RAR File?

I have received a link from a friend to download a program but its RAR file. What does it do?

If any of you have come to know ZIP files, these are files that have ZIP as the last 3 characters of the file name. You use a program called WinZip, or one of many similar zip utilities to open the file. A RAR file is essentially a condensed collection of files. Sometimes they are referred to as a library, or a cabinet of files. These files use a compression technique to shrink the files and combine them into one handy file. They then can be sent through the internet or email in parts which can be reassembled on the recipient’s computer.

Winrar is the utility used to open RAR files. Now, let’s explain a practical example. Your friend has a training video, that he wants to send you. You both have high speed internet, but don’t want to send it through the mail. What can you do?

The files in their native format are too big and difficult to organize. You would have a very hard time putting this all together again on your computer while maintaining the file and directory structure of the video. With Winrar, you collect the files and create a set of archives to be sent via email, or on a website download link. You can also create archives on your computer to save disk space. Every file on your computer can be condensed by a certain amount. This depends on the type of file and the data. Movies and Videos cannot be condensed as much as text files can be. Simply because of the type of data contained in them.

Let’s suppose that the files to be sent are 700 Mb in total. You can use winrar to create a set archive files that will create a sequential set of files for emailing. Typically, you can customize winrar to shrink the files according to speed, or level of compression. A high compression means that your computer will work harder to decompress those files at the receiving end. A faster compression means that your computer will create the archives for a quicker decompression. You may also specify the size of the archive files to output.

For example, 700 MB would create approximately 70 files of 10Mb each, with no compression. Once you have the files on your computer, locate the file with the RAR extension or the file with the lowest numbered extension (R01, R02 etc.) and open it to view the contents. Winrar will sequentially number all the pieces, with RAR being the first of the set.
To unpack, simply drag the contents of the Winrar window to your desired location. It will take some time, and you will see a progress bar. Also remember that you now have just used twice the disk space, as the extracted files are completely separate from the original RAR files you were originally sent.