Until it reaches this point, AmigaOS has some modernisation and evolution to go through. The Exec kernel is being reworked, moving to portable C code and being given additional functionality leading to "Exec SG" (second generation). For AmigaOS 4, Exec will be PowerPC native - and presumably in a state to be easily ported to other hardware (remember the Amiga "Zico" specification covered PowerPC, x86 and MIPS amongst others).
As part of development, we'll see the introduction of standards that modern desktop OSs take for granted - virtual memory, (optional) memory protection, resource tracking and management, plus a hardware abstraction layer (which makes OS portability much easier). For the benefit of Amiga users and developers, backwards compatibility with WarpOS will also be rolled into the mix. Not to mention JIT emulation for 680X0 code. Legacy applications should be well supported.
As well as Exec, other OS components are being converted to PowerPC-native versions. Intuition (the Amiga's UI system) and Reaction will move to PowerPC native, gaining an uprated look and feel, with Picasso96 compatible retargetable graphics support as standard. Backing up the enhanced UI and RTG support, AmigaOS 4.0 will add Warp3D and OpenGL/Mesa for high-performance and industry standard 3D graphics. Naturally, support for a variety of graphics cards will be included - everything from existing Zorro-based Amiga cards to modern Matrox, ATI and Voodoo devices. The use of AHI will provide similar levels of support for the audio side of things.
The FFS filesystem sees a similar move to PowerPC native implementation, rewritten as portable C code. FFS2 retains backwards FFS compatibility, while providing such improvements as better long filename support - 108 characters as opposed to the rather outdated 32 characters of old. Okay, it's not 255 characters, but it's a major improvement anyway.
AmigaOS's powerful, and still relatively unequalled, datatypes system will also get the native treatment, TrueType/OpenType font support has been mentioned, we'll see USB and native TCP/IP, and WarpInput
