Understanding File Compression Technique

Downloading a program or file sometimes becomes very annoying due to slow download speed.Thanks to ZIP files,which not only reduce the number of bit and bytes so that it can be downloaded in less time,but also take less space on disk.Now the question must be arising in your mind....how to use these ZIP files.The solution is quiet simple, you need to use an unzip software such as Winzip to expand the file to its original flavour.It takes only seconds to unzip a file.....and thus saving your valuable time which you would have wasted if you had tried to download the original full size file.

So, let me know tell me you in short how these file compression program works.Let me illustrate through an example.Suppose a file has following information in words.

"Do what you wish and do not do what you do not wish."(seems crazy but just an example)

Here you can see that many words are repeated again and again.A file compression program basically reduces this redundancy.It uses a dictionary-based algorithm to put the repeated words into a numbered index.In our case it is like(ignoring case difference)

1. do:1


2. what:2


3. you:3


4. wish:4


5. not:5

Thus the information can be read as:

"1 2 3 4 and 1 5 1 2 3 1 5 4"

Thus the file size reduces.As the size of file increases, redundancy is more thus this algorithm becomes even more efficient.But let me clearify one aspect at this point of time,though i have described the algorithm with the example of repeated words,but the file compression program, actaully, looks for repeating patterns, rather than words,indexing which into the dictionary reduces the file size as much as possible.

So, this is  the way the files get compressed and you enjoy the easy and fast download without getting irritated with your slow internet connection.