The concept of file compression is fairly simple. You take a file or group of files and you make it or them smaller and save them as a single, compressed file. The actual mechanisms can be complicated, but the simple way I always think of it is like an index. If you had a 1000 word document and replaced each occurrence of the word and with a *, you would reduce the size of the document. When you wanted to read it, you could uncompress it by replacing each * with and and you’ve got your original file back. Obviously this is the crudest example, but imagine taking a hundred-page book and compressing it to fit on a page or two without changing the font size and you begin to get the idea of how impressive modern file compression can be.
We use compressed files every day. Have you ever listened to an MP3 or downloaded an audio book? Have you ever taken a picture with a camera that saved its files in JPG format? The same song or picture that is 3.5 MB might be somewhere in the 30 to 50MB size range when uncompressed.
The ZIP file has been the standard in file compression for PCs for as long as I can remember. I used to use PKZip when I first began using compression on MS-DOS 5. I had a 200MB hard drive and much more media than would fit, so I would compress my games into smaller, single files for storage. When I wanted to play them, I would uncompress them into a temporary directory to run them.
While hard drives are bigger, so are files. The need may not exists to compress files for simple storage on our machines, but we sometimes have cause to save an entire directory as a single file. Perhaps we want to encrypt the contents of that directory before we email it. Microsoft Windows has had ZIP compression support since Windows XP, and that support has really made the use of ZIP files commonplace. There are other compressed formats, many superior to the ZIP, and it’s important that we be able to deal with these using free, secure, open source and spyware-free solutions.
Other examples of compressed file types are RAR, tar.gz, and BZIP. Many programs exist that will handle many different kinds of archives. WinZIP and WinRAR are probably the two most common, though I would argue that both are commercial, for-pay products and both are bloated. The one solution that I have found that is light-weight, completely open-source and free is 7-zip.
7-zip is small. 7-zip offers industry standard encryption across its archives. 7-zip offers seamless and transparent integration with the Windows UI, which means that all you have to do is right-click on an archive and select ‘extract here’ or ‘extract to…’ to put the contents of the compressed file wherever you want it.
7-zip offers its own compressed format which offers better compression that the standard ZIP file and I’ve been using it for quite some time. Because it’s open source, and it works on Windows, Linux and Macintosh, I don’t have to worry about having difficulties getting to my files.
I’m not the only one who likes 7-zip. 7-zip recently won an ask-the-readers competition for file compression utilities over at Lifehacker. 7-zip won two community choice awards at SourceForge in the categories of Best Project and Best Technical Design.
Do you use 7-zip? Have you found something else that works better in some aspect? Let us know in the comments.