If the mount fails…

If the mount fails, the first portion of the QNX 4 partition is probably damaged (since the driver will refuse to mount what it considers to be a corrupted filesystem).

In this case, you can use the dinit utility to overlay enough good information onto the disk to satisfy the driver:

dinit -hr /dev/hd0t79

The -r option tells dinit to rewrite:

You should now be able to reissue the mount command and once again try to create a mountpoint for a QNX 4 filesystem called /hd.

After doing this, you'll need to rebuild the bitmap with chkfsys, even on a good partition.

At least a portion of your QNX 4 filesystem should now be accessible. You can use chkfsys to examine the filesystem and recover as much data as possible.

If the hard disk is mounted as /hd (e.g., the machine boots from CD), enter:

path_on_CD/chkfsys /hd

If the hard disk is mounted as / (e.g., a network boot), enter:

network_path/chkfsys /

In either case:

What you do next depends on the result of running chkfsys.