Setting the read-only bit of a file provided only partial protection against inadvertent deletion: while commands such as del and erase would respect the attribute, other commands such as DELTREE did not.[5] Changing the system attribute was not possible in early versions of Windows, thus requiring use of ATTRIB.[5] Similarly, a system crash in early versions of Windows could lead to a situation where a temporary file had the read-only bit set and was additionally (and irrevocably) locked by the Windows OS; in this instance, booting into DOS (thus avoiding the Windows lock) and unsetting the read-only attribute with ATTRIB was the recommended way of deleting the file.[6] Manipulating the archive bit allowed users to control which files were backed up using the BACKUP command.[2]
https:// en.wikipedia.org/wiki/ATTRIB