Книга: Computer Archives: File Archiver, Proofpoint, Inc., Pronom Technical Registry, E-Mail Archiving, Archive Bit

Purchase includes free access to book updates online and a free trial membership in the publisher's book club where you can select from more than a million books without charge. Chapters: File Archiver, Proofpoint, Inc., Pronom Technical Registry, E-Mail Archiving, Archive Bit, Archive File. Excerpt: The archive bit is a binary bit . As such, it is either 1 or 0, also frequently called set (1) and clear or reset (0). It represents whether the file has (1) or has not (0) changed since the last backup.Archive bits are not affected by simply reading a file. When a file is copied, the original file's archive bit is unaffected, however the copy's archive bit will be set at the time the copy is made.In NTFS , changing the permissions of a file also re-sets the file's archive bit. However, changing other file attributes (such as hidden, -in XCOPY command), can do this as well. Because this behavior is optional, it only happens when specifically requested by the user with a command-line switch or with a configuration option.Backup software optionally clears the archive bit when making a backup copy of the file. File compression utilities such as PKZIP and WinRAR , as well as the built-in XCOPY command, can do this as well. Because this behavior is optional, it only happens when specifically requested by the user with a command-line switch or with a configuration option.Backup software offers the option to only back up files with the archive bit set , which due to the operating system's behavior, equates to all the files that have been changed in some way since the last backup when the bits were cleared . When doing so, files that have not been changed since the most recent backup are skipped. A backup made in this manner is called an incremental backup . A typical incremental backup creates a copy of all files with the archive bit set , and then clears the bit on those files as the backup is made.Backup software also provides the option to do a full backup while clearin...