Along the way, more and more data are stored into your computer hard disk. (The hard disk is the place where all your computer data are stored.) A lot of them are valuable to you. You do not want to lost them. So, it make sense to make extra copy of them and stored it into a different location (not on the same hard disk). This is backup of your data.

There are several methods of backup.

One, is to make an exact copy of your computer hard disk. Like a mirror image of the hard disk. This way, when the computer crushes or the hard disk just refuses to work properly. You can take the extra exact copy of the backup and copied it into a new or formatted hard disk. Now, you can continue using the computer from the time that you last made the backup. This method saves a lot of time by not having to reinstall all the software and running the software updates again. You do not need to create or copy all your data files again. However, this type of backup take a longer process to complete. Example, you have already used 50GB of your hard disk space. To make a 50GB of backup, you need another 50GB of hard disk or 11 DVD disks or 72 CD disks. Almost all backup are done by compressing your existing data and stored into another storage media (DVD, CD, another hard disk etc.). So, you may not need to many instead, but you get the idea. It takes a longer time to compress and store all your 50 GB of data.

Another type of backup requires you to one full backup (the method above). After a full backup is done, the next time, it will only backup the changes that you have made from the time that the last backup and now. Only the first backup takes a longer time, whereas the subsequence backup takes a shorter period of time. Time are saved on the subsequence backup. However, you may require a lot of storage media. The subsequence backup stores all the existing new and updated data. So, your backup media will store both old data, from previous backup and new data from the new backup. To save storage media used, you still need to do a full backup, maybe after every 10 subsequence backup. Example, on your 11 backup, after 1 full backup and 10 subsequence backup, its time to do a full backup again. You need to use a new storage media during this backup process, after the backup is successful. You can recycle and used the old storage media for your subsequence backup again.

Another backup is to select only that data files that are important to you. This type of backup takes the shortest time and least space. You only backup files that you want and nothing more. You just copy and paste or compress them and copied it into a backup media. That is it, simple and straight. However, in the event that your computer crushes or the hard disk stops working. You have to reinstall all the programs that you requires and do all the program updates again. It is more troublesome but you uses less backup space.

Remember that you must backup all your data in a different location form the data source. It is prefer to backup in a portable storage media. Example, DVD, CD, portable hard disk, storage media card, USB storage media, online storage space, tape etc.

You can use the backup programs that are with your computer Operating System (Windows, Mac OS, Linux etc.). You can also use commercially available backup programs. These are more flexible and provides more function. You can also use the compression/expansion program and do the backup yourselves. This is useful for the last type of backup method.