CertiGuide to A+ (A+ 4 Real)  9  Chapter 1: What are Operating Systems and How Do They Work?       9  File Management

File Management 1 Understanding Disk Compression

What to do when? Let us first understand what compression is. Compression of a file occurs when a program applies algorithms to the file to make it smaller or more compact.

Think of it like taking all the air out of a plastic bag. The reason compression is applied to a file is typically to assist in disk/drive management, as by reducing the size of one file more space is available for the storage of other files.

Besides some built in, but nicely hidden tools that come with XP there are many 3^rd party programs available to perform this function, such as WinZip or WinRAR.¹³ There is a major difference between these tools and the compression available within Windows however.

When using WinZip multiple files are actively loaded into the WinZip interface, which compresses them and writes them out into a single .ZIP file (regardless of how many files were loaded). The files are now effectively out-of-bounds and unusable until they are extracted from the ZIP file. When using Windows compression however, the compression process takes place transparently. If the compression attribute is assigned to a folder, files are compressed when they are copied in and uncompressed when they are copied out. No extra tools or interfaces are required, and the files can be used as normal regardless of compression status. The trade-off here is compression “factor”. WinZip, WinRAR and other third party tools produce a far better compression ratio than the Windows compression system. So for ease of use, choose Windows compression. For quality of compression, choose a third party tool.

Alternatively, choose no compression at all and purchase an additional hard drive. All forms of compression require processor time to perform their operations, which does have a visible impact on the apparent speed of the computer.

File Management 1 Understanding Disk Compression