Thanks for this great explanation Harry!
Sooner or later you will learn the unpleasant lesson of backups. You'll lose valuable files or important work because you don't have backups. You may lose programs, or at least lose some of their use for you because you have lost your customization. There's a lot that can go, and it can go with frightening speed. What can happen? Well, hard drives go bad and corrupt data. Operating systems go haywire and corrupt data. You incautiously delete the wrong files (there's a way around this problem, but it's another can of worms). A lightning bolt gets past your surge protector and fries your computer. Your kid decides he can fix it. You have a fire. Your friend sends you an e-mail with an attached virus. Anything at all can destroy your data.
The real question with backups is, What do you back up to? You can back up important files to 3.5 inch floppies, but each floppy will only hold a total of 1.4MBs so you're out of luck for larger files. Floppies are less stable than hard drives. Physical damage and surface corruption are more likely. Still, it will be a second copy and won't be physically on the computer.
You can back up to Zip drives (and others of the type). You should be able to get a lot of files onto a Zip disk. They are more stable than floppies, but less stable than hard drives. The disks are very expensive. You won't be able to back up much more than important files this way.
CD-RWs offer still larger space. They are very stable, but can be physically damaged. The disks are cheap. Back up programs, including the back up tool in Windows don't work with CD-RWs.
Tape Drives offer the only possiblity of backing up everything on your computer, including the stuff you forget about. They are slow and the tapes are expensive. The tapes aren't as stable as a hard drive. This is what I use. Several years ago I purchased an Iomega Ditto 2GB tape drive. It was unreliable and difficult to use. When it died I purchased a used Seagate tape drive and have been happy. Be aware that tape drive manufacturers misrepresent the capacity of their drives. That Ditto drive used 1GB tapes. The back up software compresses files before it copies them to the tape. Theoretically, they can achieve a 2-1 reduction and that's why they say the drive has a 2GB capacity. Realistically, they never achieve that theoretical reduction. 1.6-1 is more realistic. The Seagate drive is advertized as 4/8GBs (it uses 4GB tapes which can theoretically hold 8GBs of data). That's a bit more honest.
