> A good example of this
>would be A/UX on the IIfx. I'd be willing to bet the ROM code is
>slow-mode code that just accesses enough of the IOPs to work right.
>(just like the MacOS code for that machine).
>
>Also, keep in mind when the ROMs in a machine like the IIsi were written:
>Pre system 7, pre-SCSI Manager 4.3, pre 100 other advances. Trust me, there's
>plenty of room to improve performance over the code in the ROMs.

Mike,
     Yea, that was terrific, and the above is real good examples of why
it seemed to me to be a good thing, if the use of the ROM was minimized
or avoided altogether, if that was really possible.  From other responses
it seems that use is pretty  minimal at this point.  But, from what you
wrote here, I learned quite a few things (or put some pieces together I
should say)...in particular, what you had to say about the EXTENSIONS..
Good grief!  I hadn't even thought of that, and what they really are/do!
Geezzz....on this ole IIci, the extensions folder is BIGGER than the 
Internet Connection Kit (about 19.5MB) [MacOS 7.6]!  One helluva lot of
patches and stuff.....good thing all that ain't in ROM, huh?

:)
Paul