This is a process of copying and storing a different copy of files and folders in a separate storage device. Helps in retrieving a copy of the original in event of data loss. Data loss is very common to many computer users due to corruption of the computer system (windows), mostly caused by virus, theft, floods and hardware failure.
As part of plan to create a backup, it necessary to consider; what folder and files to backup, what method to use in-order to compress the folders and files like for example; Zip how often do you need to run the backup, what form of media to store the copies and for safety reasons, where do you keep the backup?.
There are several storage media that one can choose from
Magnetic tape; this is one of the most common used mode of data storage, mostly for large volume of data. The rate of reading and writing on this tapes is quite high; actually some of the modern magnetic tapes are faster than the hard-disks.
Hard disk; the capacity of the hard-disks has been improving for a number of years. Today hard-disks of large capacity are in the market, making it more competitive with magnet tape in large volume data storage. They are user friendly especially the external ones, that are normally connected to a PC through USB port. The main disadvantage is that, they easily get damaged especially during transportation.
Optical storage; Use of CD’s, DVD’s is commonly used in personal computer as they generally have low storage capacity.
Solid storage; also referred as Memory cards, USB flash disks, Compact flash and this are the most commonly used for low data volumes, compared to hard disk they are relatively more expensive in ratio of capacity and volume.
Remote backup service; Saving of data using the internet is as well gaining popularity, no form of destruction like floods, earthquakes can ever cause damage to internet saved data. Can only work for small volume of data.
For further reading visit: https://en.wikipedia.org/wiki/backup.