Anyone have experience with Acer netbooks ?

[D. Hugh Redelmeier]

| From: Lennart Sorensen <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org>

| x86-64 mandates the use of SSE for floating point, while x86 uses x87.

The AMD 64-bit architecture supports the old-style FP.  The Linux and
MS Windows ABIs have chosen not to do so.

| This makes floating point much much faster, and avoids the awfullness
| that is the x87 stack based FPU.

I've not seen why x87 stack-based FPU implementations had to be slow.

Perhaps it is the NaN (signaling and non-signalling) and denorm
support is expensive.  Is that gone from SSE?

| Most desktop machines these days come with 2+GB of ram, often 4 or 6GB,
| which means a 32bit OS simply doesn't work anymore.

Actually, too many computer systems built by big-name manufacturers
have top out at 4G just because 32-bit WinXP and Vista don't even
manage to use all of that.  In other words, the requirements of a
stupidly constrained OS encourage limited hardware.

Luckily MS has declared 64-bit to be required for Windows 7 branding.
They have held us back but are now kicking the industry forward.

(I've been running x86-64 for 4 or 5 years.  Linux was ready rather
quickly for the transition.)

I think that MS has been a little better this time than for the 16->32
bit transition.  The hacks for addressability that DOS and Windows
users had to endure were horrible (users didn't seem to blame the
perpetrator).

| PAE is a disgusting hack, has very high overhead, and is no solution.

PAE is standard practice, repeated each time memory grows beyond
address space.  I remember bank switching on the PDP-8 when memory
grew beyond 4K 12-bit words of core memory.  Unix as we know it grew
for years on the PDP-11 with 16-bit addresses but a wider address bus.

In fact PAE was designed long before most of us needed it which made
the transition orderly.  It came out with the Pentium Pro!

| Still doesn't allow more than 2GB of memory space for each application.

Carefully crafted applications can use more than 2GB of memory on a
PAE system.  They can use system calls to switch stuff in and out of
the address space.  Some applications (eg. DB systems, OSes) are so
hungry for memory that they will work hard to get it.

| You are better off loosing 800MB on a 32bit OS out of 4GB than to turn
| on PAE.  Much better.

Really?  The few real world reports of the performance hit for PAE
haven't been extreme.

| The sooner all machines are 64bit capable the better.  Why intel decided
| to make 32bit only atoms is beyond my imagination given all their other
| CPUs already have 64bit support.  Of course AMD is starting to make lower
| power Athlon II chips now, so perhaps this will make intel rethink things
| for the better.

Technical issues are one thing.  Business factors are key to
understanding this.  It is important to realize that Intel has very
good technical people and if they do something dumb technically, it is
often for business reasons (not always).

The following is "reverse engineered" logic: it may not be true, but
it makes sense to me.

Intel wanted to push everyone into ia64 (Itanium) which they would own
rather than x86 where they had to compete with other suppliers.  What
better way than slow starvation of being limited to 32-bits in x86.

There were strong rumours that Intel had designed a 64-bit x86 for the
P4 generation.  But they suppressed it.  Further rumours suggested
that this architecture was very close to the AMD64.

AMD had nothing to lose and much to win with a 64-bit x86
architecture.  They would have won even more if Microsoft had followed
through with their promise to support the new architecture well and
promptly.

The "bullet point" of supporting AMD 64 did cause a few sales.  And so
did Linux support.  But all that was insignificant in the sea of PC
sales.  They did make real inroads into the server world, but even
that was slow because that world is conservative (for good reasons and
bad).

Back to Atom:

Intel and Microsoft both feared the Atom might cannibalize their
mainstream sales (they apparently actually have).  Each company
crippled Atom systems in different ways to prevent this.

- Microsoft limits the sales of WinXP to netbooks with certain severe
  limitations (screen size, RAM, and processor, I think).

- Intel will not sell bare Atoms to anyone who will not sign a license
  that restricts on their use.  I don't remember all the limititations.

If anyone gets close to competing with Atom, the Atom will suddenly get more
powerful or the agreements will be more liberal.

We already saw how Linux on netbooks forced MS to rethink the rules
they imposed on their customers (the computer manufacturers).
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