I have a hard disk with a filesystem created by an old version of System V Unix that I would like to mount read-only on Linux. fdisk shows me:

/dev/sda1   *        2048       86015       41984   63  GNU HURD or SysV

But when I try to mount it:

mount -t sysv /dev/sda1 /mnt/tmp
mount: wrong fs type, bad option, bad superblock on /dev/sda1,
   missing codepage or helper program, or other error
   In some cases useful info is found in syslog - try
   dmesg | tail  or so

Here is what I get when I take a look at dmesg immediately after trying the mount command.

root@debian:/# dmesg | tail
[   52.495696] FS-Cache: Netfs 'cifs' registered for caching
[   52.557019] CIFS VFS: default security mechanism requested.  The default security mechanism will be upgraded from ntlm to ntlmv2 in kernel release 3.3
[  157.888559] VFS: Found a SystemV FS (block size = 1024) on device sda1
[  362.223025] sd 0:0:5:0: [sda] No Caching mode page found
[  362.223034] sd 0:0:5:0: [sda] Assuming drive cache: write through
[  362.230168] sd 0:0:5:0: [sda] No Caching mode page found
[  362.230174] sd 0:0:5:0: [sda] Assuming drive cache: write through
[  362.320058]  sda: sda1
[  362.320059]  sda1: <unixware: sda5 >
[  362.397863] VFS: unable to find oldfs superblock on device sda1

I don't seem to be able to run fsck on this file system. Here are my two attempts:

root@debian:/# fsck /dev/sda1
fsck from util-linux 2.20.1
e2fsck 1.42.5 (29-Jul-2012)
ext2fs_open2: Bad magic number in super-block
fsck.ext2: Superblock invalid, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/sda1

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>

root@debian:/# fsck -t sysv  /dev/sda1
fsck from util-linux 2.20.1
fsck: fsck.sysv: not found
fsck: error 2 while executing fsck.sysv for /dev/sda1

The file command on the drive device gives:

root@debian:/home/whg# file -s /dev/sda  
/dev/sda: sticky x86 boot sector; partition 1: ID=0x63, active, starthead 0, startsector 2048, 83968 sectors, code offset 0xc0

I'll appreciate suggestions for anything else I can try.

  • What does dmesg say?
    – miniBill
    Mar 26, 2015 at 20:37
  • I don't see anything in dmesg related to the filesystem on this drive. The SCSI driver seems to find sda OK. Mar 26, 2015 at 20:47
  • edit your question and put the results of file -s /dev/sda in it.
    – JdeBP
    Mar 26, 2015 at 21:03
  • Several of the old sysV systems used subpartition schemes on the PC (like SCO's "divvy" command) you'll probably have to decode that first and feed the results into dmsetup to slice out the portions of the drive that actually have filesystems. Mar 26, 2015 at 21:50
  • OK, I added the results of the file command to my post. Mar 26, 2015 at 22:02

1 Answer 1


Right, I just noticed in your dmesg output that the kernel found a Unixware slice:

[  362.320059]  sda1: <unixware: sda5 >

The first (and only) slice in sda1 is available at sda5. Slices are much like volumes in an Extended Partition.

Try mounting it:

mount -t sysv /dev/sda5 /mnt/tmp

As for fsck: There’s simply none available for SysV FS, as indicated by this line:

fsck: fsck.sysv: not found

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