And system caches is a solution to an unoptimized system in the first place. With an optimized system you wouldn't need that kind of caches.
Yes and no. Often caches compensate for a sub-systems latency. The CPU's instruction/data cache for example. Sure we could build computers with memory as fast as registers (other architectural issues aside), but that would cost tens of thousands of dollars per PC. So for reasons of cost we decide to make cheaper memory so that we can have more of it, and to get around it's slow access time we use some cache, which isn't as fast as a register but way better then main memory. Same goes with hard drive access. There's lots of sub systems that benefit from a cache simply because optimizing for both speed and memory (if at all possible) often means you take a huge hit in cost.
And btw, you can replace the standard WindowsXP services, but rarely does one really need to. And yes, AOS does need more built in services, that is after all what an OS is for. I mean, it really wasn't that long ago before even the GUI was an optional "service", we've just taken it for granted. Someone who's first computer was an Amiga would expect an OS to provide them with multitasking, a file system, a GUI with windows, buttons, menus and icons, audio support, etc. However things have changed and today's users demand more things, like memory protection, virtual memory, built-in TCP support with DHCP, firewall and other advanced features, built-in OpenGL (or other similar system), built-in media player with plug-in support for more codecs, etc. Expectations have gone up and it's up to the current Amiga care takers to meet those expectations.
- Mike