I'm in possession of a 100G disk that sports a partition that I have not been able to mount.

Using partx -o type on the device tells me the partition has type 0xa5, generally associated with BSD operating systems. Executing a plain mount command tells me I need to specify a filesystem type.

From the 0xa5 marker I concluded it could be some version of ufs. mount -t ufs -o ufstype=ufs2 (the default for modern FreeBSD, right?) did not yield a successful mount. dmesg complains about missing "magic numbers". Trying a number of the alternative options for ufstype has the same results.


  1. Does anyone have any tips for figuring out how to access the data on this partition?
  2. Is there a generic way to autodetect/mount partitions that I could use?

2 Answers 2


Have you verified that there is a real partition there, as opposed to random data in the block containing the partition table? (Use fdisk or cfdisk and verify that any partition start and end numbers make basic sense. fdisk at least will notice obvious things like illegal block values or end blocks before start blocks and warn you that the partition table is invalid.)

parted/gparted may be able to identify filesystems for you. Sometimes file -s can do so as well.


sudo file -Ls /dev/sdb1 will give you more information. Replace 'sdb1' with the proper device node name. cat /proc/partitions and/or dmesg | tail can help you figure out which is the correct device.

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