This must be a Troll ?
There is no AS/400 – it went away years ago. Power Systems – that run Watson, mars rovers and suchlike, now provide the computing power for the IBM i operating system. IBM i is capable of being ‘extremely’ secure, and of managing enormous workloads, in character and GUI persona. Studies and comparisons all still show that the total cost of ownership of IBM i on Power is way, way lower than, say, a forest of x86 servers. This alone, without the resurgence of capability of the OS, is enough to convince customers to install them.
I suggest the OP reads up on the current manuals, and he/she will find plenty of employment.