Automatic database checking and recovery: tcbck(ADM)
When the system is halted suddenly by power or hardware
failures, some filesystem damage can occur. Such damage
can result in the removal of security database files,
or can leave these files in an interim state if they were
being updated at the time of the system crash. Whenever a
reboot occurs, the system runs a series
of programs to check the status of the database files.
When the system terminates abnormally and is rebooted,
this check is performed after
is run on the root filesystem, prior to entering multiuser mode.
``Checking the security databases'' in the SCO OpenServer Handbook.