Overview of Compressed files and Archives

[Elbanco]

Hi,
You guys are familiar with Winzip and Winrar archives. The other thing is compressed files in Windows XP. I need an over view of this technology. First of all what is the purpose of using this features. We can send files by other medium also. And if it is a small file then why create a archive. The second thing is for what compression is used for. Does this put strain on the hard drive.

[Eric B]

A compressed file is used for several reasons. The main reason is when you want to reduce the size of a file (or multiple files). It is just handy and widely used. You can send a large size of excel file in to pieces to anywhere in the world. Hence the utility of using compressed files. You can attach any documents (Word, Excel, images, ...) into a single file. It will facilitate the work of the person receiving the email.

[Glenny]

Compress a file, it's a deal so that it can take up less disk space. The basic principle of compression is to avoid duplication, for example, instead of writing 1111111111111, it is cheaper to write that there are thirteen "1" following. The purpose of the archive is not to reduce the disk space a file but to assemble multiple files into one, to facilitate handling. It can compress files archived and compressed archive files.

[JonathanD]

In compression or creating an archive, under both cases, the file is first encoded by a program (compression or archive). But to use files (eg to read or modify them), they must be decoded. This page will teach you how to compress and decompress, archive and unpack files. Compressing saves disk space; associated with archiving, compression is very useful. In particular, the ENS, the disk resources are not unlimited.

[Macarenas]

By definition, a compressed file will occupy less space, regardless of the medium where it is, what is interesting in both the database server on your hard drive. Its weight is lighter and transfer time on the network will consequently shorter, as if to repatriate a browser that weighs about 20 MB and more. Utilities like Winzip or Winrar are used widely for this purpose. compression is used to condense the repetitive data contained in a file shorter codes that use less space. And already stated in the preamble, other software used to extract this information and give them back their original form.

[ThoMas321]

There are several methods of compression, but the main techniques used are based on mathematical equations (algorithms = sequence of operations) that rely primarily on the treatment of redundancies (code that uses a number of symbols greater than it is necessary to represent the information given) and also rehearsals, which are then replaced by shorter codes. For images the goal is identical and can be replaced by e.g a single 3-color code is identical in composition according to the chart, but be careful choosing a compression ratio too high tends to alter its definition. (JPEGs are particularly susceptible to compression, the GIF are less sensitive but limited to 256 colors)