Back to Internet 101

Question: What is a file compression?

Answer: File compression refers to a variety of techniques that allow the size of a file to be reduced. This compression allows the time to transfer the file over the internet to also be greatly reduced.

File Compression can cut down the file size dramatically. Once you download this compressed file it is necessary to have a decompression program to extract the file. This decompression process puts the files back into their original format so your computer can read the files or run the programs.

You've probably heard of WinZip for the Windows platform or Stuffit Expander for the Macintosh. These are two widely used decompression utilities.

When a file is compressed, the compression program scans the file (or files) and searches for patterns through a process of complex mathematical equations. These patterns are replaced with smaller segments of code that can later be translated back into their original format.

How much can a file be compressed? Well, that depends on the type of file. If the file is a text file - I've seen text files compressed as much as one-fifth their original size. Programs on the other hand are often only reduced about 10%.

TIP When you decompress a file, it is always best to put the file in an empty folder. You never know how many files will be in an archive and it can be difficult if not impossible to sort through all the necessary files if you decide to move them later.

Question: What are the most common compression techniques used?

    Answer: Probably the most common types of file compression are .zip, .sit, and .tar. These three types of compression are pretty much the standards for PC, Macintosh, and UNIX respectfully.
Question: What is a self-extracting file?

    Answer: A self-extracting file refers to a file that has a small program built into it that allows the archive to be extracted without the necessity of having the decompression program. Self extracting files are usually in the .sea format for the Macintosh and .exe for Windows.
Question: Do I have to worry about virus within an archive?

    Answer: Yes. Not always intentionally, but archives often contain viruses in them. If you download files from the internet, it is highly recommended that you have a good virus program installed. The good virus programs can scan archives while downloading or when extracting the information and will notify you if you encounter a virus.

6966

Back to Internet 101