System Administration Guide, Volume 1

End-of-Media Detection

The ufsdump command automatically detects the end-of-media for most devices. Therefore, you do not usually need to use the -c, -d, -s, and -t options to perform multivolume backups.

The only time you need to use the end-of-media options is when ufsdump does not understand the way the device detects the end-of-media or you are going to restore the files on a system with an older version of the restore command. To ensure compatibility with older versions of the restore command, the size option can still force ufsdump to go to the next tape or diskette before reaching the end of the current tape or diskette.