A Good Backup is Critical to Data Recovery by Thomas Husnik Copyright (c) 2008 Thomas Husnik

We are sometimes spoiled these days when it comes to data and software on our personal computers. We can store so much of it on one disk drive and we can retrieve it very quickly. And these personal computers just hum along for week after week with no problems whatsoever. We are even prudent in backing up our "My Documents" folder to a re-writable CD once in awhile.
Until one day, you computer does not boot up. You take it to a computer repair shop and they replace the disk drive, reload Windows, and deliver it back to you. You then reload your Microsoft Office, copy back your "My Documents Folder" from your CD-RW disc and you should be back in business. Except a short time later you find out that you are missing that spreadsheet that took days to build. What happened? Then you remember that you had stored the spreadsheet on the C: spreadsheets folder and not "My Documents." The spreadsheet and all the work that went into it is gone—forever.
The above scenario happens way too often in today's world that is so dependent on computer information. The point you should see here is that even though the user was doing a backup, the backup did not include everything required in order to one day do a successful recovery. While our example is simple, imagine a computer where there are data files stored all over the disk in many different folders other than "My Documents." And in most cases a couple of CD-RW disks are too small to backup everything. You need to acquire and implement a backup system and strategy that gives you the space required to store all your critical files plus one that allows you to backup and recover quickly.
Backups are typically done using tape or external hard disk drives. The latter is becoming more and more popular because of the speed of the backup media. An external hard drive can basically be a mirror of your internal hard drive. However, you don't have the redundancy (multiple copies) of disk files that you could get with tape unless you purchase several disk drives (which could be expensive). But, with an external drive, you can just copy folders from your system drive to your external drive and you have a quick data backup that is very easy to recover.
The other long-time popular method for doing backups is tape. Tape backups have been around for a long time and for good reason. You can store an incredible amount of data on one tape and you get the benefit of being able to take that tape and store it at some alternate location so that you can recover in the event of some physical disaster such as fire, theft, or flood. If you stored external disk drives offsite, you would lose the benefit of being able to use that drive. There are a couple of drawbacks to tape. One is that tape breaks much easier than an external drive. The other is that tape drives come with proprietary software in order to compress and transfer data to the vendor's model of drive. In other words, they are not native to the operating system like Microsoft Windows. But it usually is only a matter of installing the software on the computer system you are recovering the data to.
There are many variations to tape and external disk drive backups but the important thing to remember is that you cannot recover if you do not properly back up. You should periodically test your recovery plan so that you know it is ready when you need it.

About the Author
My name is Tom Husnik. The site that helped me is : http://www.diy-computer-repair.com/