File Compression Definition | The Interactive Glossary

File compression is accomplished with software that uses mathematical equations (algorithms) to condense repeated data into smaller codes. You need another separate software program to decompress (expand) the data, and restore it to its original form.

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Frequently Asked Questions

With larger hard drives and high-speed Internet, do we still need file compression?

File compression will always be handy. While most computer hard drives grow substantially from year to year, we use devices with smaller hard drives every day. In fact, many smartphones have storage capacities smaller than computers did ten years ago. As more of our personal and business computing moves to portable devices and we continue to demand them thinner and lighter, the need for file compression is all-but guaranteed to persevere.

What’s more, as storage capacities increase, so too do file sizes. There was a time you could fit dozens of digital photos on a 1.44 MB floppy disk; now we have cameras that create image files so large, you can only fit a handful on a CD-Rom. At the same time, the Internet has become more image-intensive. Trying to view a webpage filled with full-size images shot by a modern digital camera would take forever…not to mention how much space they would take up on a server. So these images are compressed into a smaller file format before getting uploaded to the Web. Likewise, movie files, programs, and even our word processing documents have grown in size, as we continue to demand more from them.

Can any file be compressed?

Some files compress very well, while others may not compress much or at all. Media files, in particular, do not compress well, because most media formats already utilize compression technology. There is only so far you can compress a file before it begins to lose integrity and the original content can no longer be preserved. On the other hand, text documents and bitmap image files can often be substantially compressed.

When should I compress a file?

There are plenty of times file compression comes in handy. If you are emailing a file to someone, depending on the size of it, you may need to compress it first, because many email servers limit the size of messages they can send or receive. If you are sending several files at one time, such as your holiday photo collection, compressing them into one file not only makes it easier to manage but can also save you from having to split them between several emails. If you need to send files over a slow Internet connection, compressing the files first can considerably reduce the transfer time. Image files are often compressed to a smaller format to enable easier sharing or prepare them for the Web. If you create a backup image of your hard drive, many programs will compress the image, so it can be stored on removable media. Anytime you need to transfer or store files that are too large, file compression can help.