File compression

File compression works because document files store data quickly and inefficiently – like carelessly throwing clothes in a suitcase before a trip. Taking more time and care makes it possible to pack more in the case.

File compression tools are like vacuum luggage packs that squeeze half as much again into your bag.

You could be forgiven for thinking file compression is past its sell-by date in this era of huge hard drives and broadband. Compression is still useful because broadband speeds are still not spectacular and modern multimedia files are enormous.

You probably use compression all the time without thinking about it because it is hidden from sight.

Take, audio. A file on a standard music CD is many tens of megabytes in size – typically 50 MB. The same song stored as an MP3 file might be only 4MB. MP3 is a compressed data format – in effect it squeezes out the blanks between sounds.

If music wasn’t compressed, you wouldn’t be able to get many songs on an iPod and it would take forever to download from iTunes. Compression removes some music information along the way – that’s why MP3s rarely sound as good as the original audio files.

In a similar way jpeg compresses pictures and movies are compressed with a range of different formats.

Compression is not built-in to office applications like word processors and spreadsheets. Third-party compression tools to fill the gap.

Zip is the best known file compression format. Another popular format is .rar, there’s a good chance you’ll come across other formats.

Windows now has built-in support for Zip files. You can create a new compressed folder or create a new one directly in Windows explorer. Dealing with other formats requires a compression application – most, including some of the best are free. My favourite is jZip ( JZip is a fast tool that handles most formats you’ll encounter in day-to-day computing.

You don’t need to overdo compression. In many cases it is more trouble than it is worth because it slows things down. Be selective about what you compress.