Compression

• The process of reducing the volume of data by applying compression technique is called Compression.
• The reduced data is called compressed data.

Decompression

• The reverse process of reducing the original data from compressed data is called Decompression.
• The resulting data is called decompressed data.

Compression types

• Compression divided into two types lossy and lossless see below figure.

Compression Utilities

• There are normally used compression utilities Win RAR and Winzip.

WinRAR

• WinRAR is a trialware file archiver utility for Windows. It can create archives in RAR or ZIP file formats, and unpack numerous archive file formats. Itsupports lossless data compression.
• Below figure shows the how to compress the a folder using WinRAR software.

• Below figure shows the how to decompress the a folder using WinRAR software.

Winzip

• ZIP is an archive file format that supports lossless data compression. A .zip file may contain one or more files or directories that may have been compressed.
• The .zip file format permits a number of compression algorithms, though DEFLATE is the most common. Zip files are compressed to save space.
• Below figure shows the how to compress the a folder using Winzip software.

• Below figure shows the how to decompress the a folder using Winzip software.

Advantages of Compression

• Reduce file size.
• Provide security.
• Save disk space.
• Increase transfer speed at a given data rate.
• Allow real-time transfer at a given data rate.

Disadvantages of Compression

• Lose the the data.
• Lose the quality.
• Some times we can forgot the password we lose the data.