OS/400 V3
OS/400 V3
OS/400 (now known as IBM i, previously i5/OS) is the operating system of the AS/400 (now Power Systems, previously System i) series of minicomputers by IBM. It is the replacement for CPF for the System/38 and SSP for the System/36. In addition to a consistent programming environment and a user-friendly interface, it features advanced features not seen in other platforms such as tagged memory, single-level storage, is exclusively written in managed languages.
Comments
Due to the unique nature of OS/400 it might be possible to reverse-engineer the TIMI VM and perform some kind of HLE, but it'd definitely require some gargantuan amount of work.
These are big proprietary systems that are nothing at all like a PC.
And yes, it's true: the classic 400s are some really weird beast, probably even more than their mainframe counterparts, as their design choices (up to the point when they finally integrated all in the System p line) really hark back to the S/38 days.