Imagine you are working on a presentation late at night and poof… suddenly the hard disk of your computer crashes. This results in the loss of a hard disk which may be replaced or repaired by the manufacturer depending upon when you bought it. However, what cannot be replaced are the documents, address book, maybe financial information and the presentation that you need to present to your boss in the morning. It may take you weeks to retrieve all this information.

There is no doubt that you need to protect your data from loss as it contains your important documents and files which were prepared with months and sometimes years of efforts. Data protection is of two types:

• Data backup and restore: In this option, we need to back up the data as per our schedule. Whenever needed, we can restore the data from the backup. The data which was created or modified after the backup was taken is lost when we restore the backup.
• Data recovery. In this option, there are data recovery utilities which can help you recover your data even if you have not previously backed up your data.

To understand why you need to use online backup services, consider the reasons why you should backup your data in the first place. The answers are obvious – to protect against hard disk failures, unintended deletions and other causes of data loss. Online backup services come in picture in the other causes.

The cheapest way to backup your data is to use external devices like CD/DVD or USB drives.
Let us consider the features of the external media currently available:

1. CD-ROM Disks: One of the cheapest backup media available, the CD can store about 700 MB of data. One can easily store data on a CD with the help of CD-writers which are common in most computers available today.
2. DVD-ROM Disks: These are a bit costlier than CDs but considering that one DVD disk can store 4.2 GB of data; the cost per GB is less as compared to CD.
3. USB Drive: Falling memory prices have made these backup media very cost effective. The additional advantage of these drives is that they can be reused many times unlike the CD/DVD. The only drawback is that usually a USB drive is required on the computer which may not be present in all computers.

Tapes are the earliest forms of data backup. A tape media consists of a long flexible ribbon made of flexible plastic coated with magnetic media. The tape is wound on spindles and stored in mechanical cartridges that protect it from dust.
 
Backups made to tape media are mostly used in corporate environments due the following reasons: