AIX

Nice one that worked..... Now to find out why the unix_up file didn't copy over in the first place!

Glad it worked for you!

re: how - If you still have the system - see if the file is still there. Could have been removed by accident. Does not happen often, and I forget "how they did it", but this is actually something that "went wrong" every now and then during AIX administration classes.

This is why/how I knew "what to do", rather suggest, when I saw your earlier post.

In short, cannot put on backup if the file is unlinked.

If I recall, it was something about people not wanting /unix to be a symbolic link (not what they were used to) and they "fixed it" - to their demise.

Some history: the origin of the symbolic link goes back to the days when you could boot as mp or up kernel (multi-processor or uni-processor). The up kernel was slightly faster on a uni-processor system but did not work on a multi-processor system. The mp kernel worked on both (so the boot program on installation media was always mp based). In short, on a uni-processor system you could swap between up or mp kernel by changing the link and creating the bosboot again.
Later this was also used to support switching between 32 and 64 bit kernels.
Now there is only the unix_64 kernel. (AIX 6.X and later)