On Thu, 8 Mar 2001, Jason R Thorpe wrote:

# Hey, even 4.4BSD broke with "the BSD way" -- it got a brand-new virtual
# memory system from Mach, an operating system with a completely different
# architecture than BSD.  Should it have kept BSD VM instead?  I think that
# pretty much everyone agrees that the step to Mach VM was a good one (even
# if it did have some room for improvement, which NetBSD has since done,
# we now have UVM, which borrowed some concepts from, *gasp*, Solaris,
# and UBC which borrows some concepts from, *gasp*, Digital UNIX).

Speaking of UVM/UBC, I notice that they have somewhat, if not completely,
edged out the page_zero_idle() loop...or has it?

I realise it's not trivial to keep a buffer cache and a cache of empty
pages available at the same time, especially on a busy system, but it
seemed to me that with that loop, having zeroed pages ready for processes
on demand, things were a bit snappier.

# 4.3BSD and 4.4BSD are old technology at this point, and in order to
# survive, we (NetBSD) must evolve, as we have done and will continue
# to do.  As people demand more power and flexibility from their computer
# systems, we, as the provider of system software, must adapt to those
# demands.  That's not to say that we are going to throw away all vestiges
# of BSD (quite the contrary -- we're all here because we *like* the way
# BSD did things!), but sometimes, in order to improve, you have to change
# the way things are done.  That is not a bad thing.

I think I've even gotta agree with this.  If we do not proceed, we stagnate,
grow old and die.

As long as we can implement things in an optional fashion, as well as
a sensible one, we will not only survive, we will thrive, even if in a
small marsh.  At least it's not an aquarium (talk about stagnant).

So far, I see NetBSD as having evolved in the most natural fashion; if
BSD development were still continuing in the CSRG today, I think it
would look an awful like what we have now -- I can't see the likes of
them dictating, as some may surmise, that we wouldn't be supporting
different architectures or other niceties like sound cards and graphic
displays.  The only difference I can see is that SMP would probably have
been finished by now because the CSRG, as an entity, was funded.

But that's (*(*can_of_worms[])(*)()) another;

#         -- Jason R. Thorpe <thorpej@zembu.com>

				--*greywolf;
--
*BSD: making all computer hardware a commodity.