Because disks occasionally become defective, the wise computer user protects (him/her)self by making backup copies of his/her data. After you have put in 50 hours or more of work preparing a large project, you don't want to find yourself having to start over due to a defective disk. Protect yourself - make a backup copy of your work on another disk. It takes very little time, and may save you a great deal of time.

There are several ways to make backups. Notice also that individual files or entire disks may be copied. Recall also that some backups are legal, and some are not. Don't make illegal copies.

Individual files may be copied from disk to disk in various ways. If the file you wish to copy is a data file from an application program such as MS Word or Excel, an easy way to copy the file is as follows: While using the application program, retrieve the file from your (first) data disk, then perform a Save As operation in which the second disk is the target of your save. Here, by "disk" is meant any of a hard drive, flash drive, cloud service (Google Drive, Dropbox, etc.), etc.

A file may also be copied via Windows (or even DOS) copy operations. If the disk you wish to copy from and the disk you wish to copy to cannot be active at the same time (for example, if you wish to copy from a flash drive to another flash drive and the computer you're working on only has one available USB port), this is typically done by copying the file from the first data disk to the hard drive, then from the hard drive to the second data disk. You might then delete the file from the hard drive. This is particularly important if the computer you're using is someone else's, such as the University's, as it's inconsiderate to fill someone else's hard drive with your data files.

More advanced (but easy) techniques allow you to copy multiple files with a single command.