Data Compression is a process by which files and folders are reduced in size so that it can be managed better for some file operations such as file transfer, web use and archiving. There are several softwares or utilities such as rar, zip, lzma, lzop etc that perform compression and/or archiving, each with its own advantages and disadvantages.
There are several desirable attributes that a compression software should have.
Speed is always desirable whether you are compressing, decompressing or transferring files. The software should have a high compression speed especially for large files. The following softwares are designed specifically for speed and often provide the best results.
LZmat: This is a data compression library designed specifically for speed.
QuickLZ: This is another of the compression libraries which claims to be the fastest library for data compression.
Lzop: Lzop is a utility which uses the LZO compression algorithm. It produces compressed files which are slightly larger than other utilities but is very faster.
While the compression speed is important, so is the decompression speed. You should be able to get the file back in a reasonable amount of time.
Lzop: Though also known for its compression speeds, this library is designed and known better for its decompression speeds.
LZMat: Again this has some good decompression speed.
Another important requirement is the compression ratio or data compression ratio. The data compression ratio is defined as the ratio between the size of the compressed file against the original un-compressed size of the file. Smaller the ratio better the compression.
UHARC: This is a little known algorithm which produces the greatest compression ratios. It also has a Windows GUI called WinUHA.
7Zip: 7Zip is another one of the utilities which produces a very good compression ratio for most file types.
There are certain factors which affect the above metrics.
The type of file and how the data is represented affects the compression metrics quite a bit. For example, the compression softwares that work best for text files may not perform well on image files.
Memory or RAM
Speed usually comes at the cost of memory. In order to achieve high speeds that the algorithmn provide, you will need to have enough memory on your system.
The utilities mentioned above are some of the lesser known ones which tries to focus on one of parameter and does it well. If you are looking for a software which provides overall good performance across all parameters for everyday purposes, then you might be better off with any of the better known formats and softwares such gzip, 7z, zip or rar.