FSIOP, IPCS, Netfinity Server, call it what you want. You can run a number of OS's on them. The name changes also indicate the changes in the card. The AS/400 can have multipal PC cards in them.
They started out with the FSIOP with a Pentuim PRO200 on them. I think the max RAM was 128MB. You can run OS/2, Novell, WinNT 4.0 on the card.
The IPCS was a Pentium II 333MHz wit a max of 516MB of RAM. IPCS would run Novell, OS/2, WinNT4.0. Not much changed there.
The new Netfinity has a Pentium III 800Mhz with a max of 2Gb of ram. The only OS's that can run on the newest card are NT 4.0, Win2K Server, and no linux is not yet supported on the new card. IBM has given up on letting it run on just the Nefinity card. Linux can be installed on a secondary partition on the AS/400 under the LPAR(logical Partion) rules.