There are two different types of backup supported: File backup and system image. File backups are saved to ZIP files. Two types of file backup are supported: The first type, normal backup, stores everything selected for backup. The second type, incremental backup stores only files that are changed after a previous backup. However, unlike the file backup and NTBackup, in which data are backed up file by file, system image is a disk image of the backed up system saved block by block in a VHD file. Block-based backup is more efficient at performing subsequent differential backups, as only the blocks that have changed need to be backed up.
During a backup, Windows uses Volume Shadow Copy Service to ensure that files are not changed while they are being backed up. Newer backup media such as CD, DVD and Blu-ray discs are supported in Backup and Restore.
Windows Backup service is the Windows service responsible for backup and restore operation. The Backup and Restore application however, is not the only way of interfacing with this service: The Wbadmin command-line utility may also be used.
System image
The image-based full system backup option, called Complete PC Backup in Windows Vista or system image in Windows 7, allows for the imaging of the entire system including operating system and data volumes. The backed up image can later be restored through the Windows Recovery Environment either to the same computer or to a new computer of different brand and type. The file format used when doing an