System backup Disk image

some backup programs user files; boot information , files locked operating system, such in use @ time of backup, may not saved on operating systems. disk image contains files, faithfully replicating data. reason, used backing cds , dvds.

files don t belong installed programs can backed file-based backup software, , preferred because file-based backup saves more time or space because never copy unused space (as bit-identical image does), capable of incremental backups, , have more flexibility. files of installed programs, file-based backup solutions may fail reproduce necessary characteristics, particularly windows systems. example, in windows registry keys use short filenames, not reproduced file-based backup, commercial software uses copy protection cause problems if file moved different disk sector, , file-based backups not reproduce metadata such security attributes. creating bit-identical disk image 1 way ensure system backup original. bit-identical images can made in linux dd, available on live cds.

most commercial imaging software user-friendly , automatic may not create bit-identical images. these programs have of same advantages, except may allow restoring partitions of different size or file-allocation size, , may not put files on same exact sector. additionally, if not support windows vista, may move or realign partitions , make vista unbootable (see windows vista startup process).