Ole Holm Nielsen wrote:
>
> Besides corrupted tapes, are there any known software problems for the
> mksysb command and the tapes produced ?  I'm really worried by your
> statements.
>

The mksys command is a shell script. It does not, in most cases, check
the exit values returned by commands. When I researched mksys problem
reports on the Web I found a copy of a console log that shows very
clearly why this is a problem. Early on there was a message reporting
that an fsf operation (the File Space Forward function of the tctl
command) had failed because of a media problem. At the bottom of the
log there was a message from mksysb announcing successful completion.
Because the script did not check the exit values of its tctl commands,
it reported that all was well, even though one of the tctl commands
had encountered an error that was almost certainly incompatible with
generating a usable tape. I suspect that our mksysb failures stem from
this family of design errors, but I do not have absolute proof.

In the course of the Web search mentioned above, I also ran into a
report of mksysb problems caused by the tar command's limitations on
the length of relative path names for files to be copied from disk
to tape. I don't think this was the source of my site's problems; I
would expect it to lead to consistent rather than intermittent
failures. This problem is apparently specific to AIX 3.