A/UX: "bad sblock magic number" Error When Backing Up

  • Last Modified: November 11, 1992
  • Article: TA28609
  • Old Article: 10944
When creating a backup of an A/UX filesystem, I get the following message:

DUMP: bad sblock magic number
DUMP: The ENTIRE dump is aborted.
The dump.bsd command takes as its last argument the raw device file, rather
than a block device (directory name). For all filesystems except the root
filesystem, dump.bsd will look up the block device in /etc/fstab and use the
raw device file listed there.

This error can be reproduced as follows:

# dump.bsd 0f /dev/null /
DUMP: Date of this level 0 dump: Wed Oct 21 12:29:00 1992
DUMP: Date of last level 0 dump: the epoch
DUMP: Dumping / to /dev/null
DUMP: bad sblock magic number
DUMP: The ENTIRE dump is aborted.

Replacing the block device with the raw device in the example above
will allow the dump.bsd command to execute correctly:

# dump.bsd 0f /dev/null /dev/rdsk/c0d0s0
DUMP: Date of this level 0 dump: Wed Oct 21 12:43:56 1992
DUMP: Date of last level 0 dump: the epoch
DUMP: Dumping /dev/rdsk/c0d0s0 to /dev/null
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (Pass II) [directories]
DUMP: dumping (Pass IV) [regular files]