Glossary

A backup is a copy of one or more files created as an alternate in case the original data is lost or becomes unusable. For example, you may save several copies of a research paper on your hard drive as backup files in case you decide to use a previous revision. Better yet, you could save the backups to a USB flash disk, which would also protect the files if the hard drive failed.

Hard drives are meant to run for many years without crashing. But just like all electronic devices, they are not immune to problems. Because they are not solid state devices, hard drives rely on moving parts to access data, which can malfunction and cause your data to become unrecoverable. If you need proof of how fragile hard drives really are, go to your local computer store and have someone show you an open hard drive. When you realize all your data is stored in such a small, delicate device, you may have a new understanding of why you need to backup your data.

But it's not just hardware malfunctions you have to worry about. Software corruption can also damage your files. Directory structures can become damaged and cause entire folders to disappear. Files can be mistakenly deleted or corrupted by viruses or other software attacks. Program installation conflicts can make applications or files unusable. There are unfortunately many ways for your data to become damaged or disappear.