Even with an MMU, the cache buffers are likely to be vunerable to random
pointers depending on the implementation of the filesystem. The buffers
need to be in memory which is accessible to various tasks. Buffers could
be tagged READ_ONLY, etc, but at least under any likely AmigaDOS MMU
schemes there would be a significant speed penalty if you want to make
buffers untouchable by errant pointers. But that's all rather academic at
this point on the Amiga.