Think about the number 70,000,000,000,000,000,000,000,000. Imagine trying to read this number to someone else so they can write it down. You can say "seven zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero, zero." It would be much easier to say "seven followed by 25 zeros". You have effectively compressed the information into fewer words, and the other person can uncompress it by actually writing out the 25 zeros.

     Many files are full of repetitions such as multiple spaces. This means they can be compressed. It is easy to see how you can compress a file like this by indicating the repeated character and the number of times it should be repeated.

     Some files that you download may be compressed. For the Windows environment these compressed files have a .zip ending. For the Macintosh, these compressed files have an .hqx ending.

 

     To uncompress a .zip file, you will first need to follow these directions:

  1. Download the latest version of the popular program, WinZip - www.winzip.com.
  2. Double click on the executable file that was downloaded - winzip.exe.
  3. It will ask you to install to C:\Program Files\WinZip. Click on OK.
  4. At the "Thank you for installing WinZip" window, click Next.
  5. In the "License Agreement and Warranty Disclaimer" window, select the radio button in front of "Start with WinZip classic". Click Next.
  6. In the next window, click Next.
  7. "Express set (recommended)" should be selected, click Next.
  8. In the "Thank you for installing this evaluation version" window, click Finish.
  9. Click on the Close button.
  10. Click x to close the window.

     If you have downloaded a zipped file to your desktop, then follow these steps:

  1. Find the file and double click the zipped file (.zip).
  2. Click on I agree in the "Thank you for trying WinZip" window.
  3. Double click on readme file (.txt) and follow the directions for placing the file.

     Stuffit Expander - www.aladdinsys.com is another program that allows you to uncompress files on either a Mac or PC. This program uncompresses .hqx (BinHex), and .sit (Stuffit) files; these files are Macintosh files. It also provides an alternative method for uncompressing .zip files which indicates Windows formatted files.

To use Stuffit Expander, follow these steps:

  1. With Stuffit Expander on your computer, download a compressed file and Stuffit Expander will uncompress the file and then save it to your computer.
  2. You can drag an uncompressed file to wherever you want to store it on your hard drive.

         



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    University of Northern Colorado, Greeley, CO