Backup is an operation where the data is copied to a device for preserving the data or to restore the data in case of a failure of the hard disk.
Often, big corporations and mainframes have a regular backup activity where data is regularly backed up. The data is copied onto backup devices like the Tape Drive or a Magneto Optical drive that have the capacity to hold large amounts of data.
For small businesses or home purposes, data is copied onto a cheaper medium like floppy disks, rewritable CD’s or Zip drives.
Bigger businesses use tape drives to store large amounts of data. Tape drives store many gigabytes of data and the cost per MB of storage for a tape drive is less.
The backup operation is generally scheduled at a fixed time by the admin, and the operating system backups the selected files to the drive to be restored at a later date.