18 Sep
1998
18 Sep
'98
4:38 a.m.
On Fri, 18 Sep 1998, Kevin McQuiggin wrote:
Intel x86 series have anything _but_ a flat 32 bit
address space! The flat
memory model is one of the positive features of the 68K series. I taught a
computer architecture course a couple of summers ago and one of the most
challenging parts of the course was explaining the addressing schemes used
on the 386 and above.
True, the architecture is quite "rich", but it's trivial to make the
address space look flat, and that's what most PC operating systems do
today. Segments could have been a very powerful feature if Intel had just
given us more of them. Imagine having every data object in its own
segment which hardware access protection and boundary checking. This
would have been a huge boon to software reliability, but they only gave us
4096 of them!
-- Doug