A/UX: How To Recover "dev/syscon"



Article Change History
----------------------
08/31/92 - REVIEWED
* For technical accuracy.
08/31/92 - Updated
* Removed obsolete information.



This article discusses what happens when the "dev/syscon" file is corrupted and
two ways to recover.

--- problem description ------
On system startup, the system went to the point where it checks the total
amount of memory and hung. It didn't get to the point where it asks if a check
of the file system should be made.

Running "esch -v" returned the system messages:

Running autorecovery esch -v
fscheck - dev/dsk/c5d0s0

The system completed phases 1, 2, and 3 of the file system check with no
problems. Then, in phase 4, it found problems:

free inode count wrong and superblk -- fixed
file system modified

It went through a few other file systems. Then, in the section where A/UX
starts validating the files, it showed a permissions error on major/minor
device number. Then, it showed replacing "/dev/syscon".

It started validating other files. Then, it bombed leaving these messages:

/dev/syscon was not replaceable
exiting file check.

After this, you cannot get his kernel up and running nor can you launch on
"/newunix".

Most likely, the "/dev/syscon" file was corrupted. There are two
ways you might be able to recover it from SASH:

Here are the two ways:

a. Directly copy /dev/syscon from one of the Eschatology partitions.

For example:

pname -s 3 "Eschatology 1"
rm -f /dev/syscon /dev/console /dev/systty
cp (0,0,3)/dev/syscon /dev/syscon
ln /dev/syscon /dev/console
ln /dev/syscon /dev/systty

b. Create /dev/syscon from scratch.

rm -f /dev/syscon /dev/console /dev/systty
mknod /dev/syscon c 7 0
chmod 722 /dev/syscon
ln /dev/syscon /dev/console
ln /dev/syscon /dev/systty

Note that "/dev/console", "/dev/syscon", and "/dev/systty" are all hard-linked.


Published Date: Feb 18, 2012