What is Data Compression

What is data compression – How does it help us – Which file compression software or tools do we need to use?

What is Data Compression

Data or file compression as it is commonly known enables a files size to be shrunk or compressed to a percentage of there original size.

How does this work?
A file compression application such as below examines the file you wish to compress then it basically deflates the file by removing data within the file that is either empty or repeated, it then creates a flag/pointer to the location of the spaces and repeated data, the flag takes up much less space than either the space or repeated data area, this then points to the space or data which is stored in a single area making storing the data much more efficient size wise.

When the file is uncompressed back to its original size the spaces and the repeated data are then moved back into there original locations, kind of like re-inflating the file.

To reduce the size of a file compression software applications are used; common applications include Winzip or WinRar.

Winzip will give a .ZIP extension and WinRar will give a .RAR extension, both of these applications offer very good compression and can be downloaded free.

The percentage that files can be compressed by depends on the original file type, database files and complete computer images compress really well as they generally do not have much, if any built in compression, but files which already have built in compression such as video MP4 files, or audio files such as MP3 cannot usually be compressed by anything as the compression is already very good, in fact trying to compress a file type which already has built in compression can result in the new compressed file being larger than the original file.

Advantages of Compressing Files

• Making a file smaller means it occupies less space.
• Larger files can be sent via email when compressed.
• An extra layer of security can be added when a compressed archive has password protection.

Disadvantages of Compressing Files

• Not all antivirus software packages will scan compressed files or archives, this then means a computer is somewhat exposed to a virus or malware.
• If you email a compressed file will the email recipient be able to open the file? Its always useful to add a link to download the file compression software being used to compress the file.

Notes

Always check the file type before you compress the file, there is really very little point in compressing certain file types that already contain compression, a good test is to compress the file anyway and then check the size of the original file against the archive.

Always use popular archiving methods using software that is easy to obtain, after all compressing files using unknown products may prove difficult to expand them if ever you reinstall the software, but cannot find the website to download from.

You will also find that popular file compression software such as WinZip or WinRar offers many more features such as..

• Good levels of security,
• The ability to use different levels of compression such as less compression, but faster to compress or maximum compression, but longer to compress.
• Spanning, which allows a single compressed file to be broken down and stored on multiple media.

What is data compression in images - which image file types have built in compression

Even your operating system uses compression - find out more about NTFS

computer adviser what is data compression article