Mailinglist Archive: opensuse (5130 mails)

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Re: [SLE] Totally OT: 64/32,... -- memory models are _everything_ to programs
  • From: "Bryan J. Smith" <b.j.smith@xxxxxxxx>
  • Date: Sun, 14 May 2006 23:40:24 -0400
  • Message-id: <1147664424.3069.27.camel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
On Mon, 2006-05-15 at 00:23 +0200, Orn E. Hansen wrote:
> Ok, I'm sorry to barge in here, I did rename the thread above.
> I find this just "bonkers" ... "Linux does _not_ want ...".
> An AMD64 processor, was designed to be able to run code from both worlds,
> for the purpose of backwards compatibility.

>From the standpoint of PAE 52-bit programs _co-existing_ with 32-bit or
even PAE 36-bit programs, _yes_.

But from the standpoint of PAE 52-bit programs calling 32-bit or PAE
36-bit libraries, or 32-bit or PAE 36-bit programs calling PAE 52-bit
programs, *NO*. *PLEASE* read my blog article. Please understand how
memory models work. This is not a "solvable problem" in software.

It is _nothing_new_. It's plagued DOS, various extenders, DPMI, OS/2,
Win16, Win32s, Win32, etc...

Yes, again, a PAE 52-bit kernel can run _both_ PAE 52-bit and 32-bit or
PAE 36-bit programs. But that doesn't necessarily mean the two can work
together. Again, program/library memory models are the problem.

> It's the user who decides what he wants, not you or I.

Sigh. You _utterly_ missed my point. Sigh. I'm talking about the
_technical_reality_ of how memory models work. x86-64 is _no_different_
-- it's just another memory model.

> If the user wants to be able to run some 32bit software, then it should
> be the PRIDE of Linux programmers, to provide the best solution to do
> so ... not come around, as, telling people to go hide in a bunker,
> because the GOD LINUX doesn't want it, and so he won't get it.

Sigh. Windows XP x64 is ... guess what? Largely a _32-bit_ OS!

You'll often get _better_ performance out of running Win32 applications
on a Win32 OS, than Win64 programs on a Win64 OS, because it's still
largely Win32! Only now Microsoft is using WoW to do all sorts of
real-time call address and object translation to have those 64-bit
programs call _core_ 32-bit libraries. And going the other way is even
worse.

In _all_ cases it's a _major_ performance hit! And it's _not_ "native."

All Linux x86-64 releases have been natively made PAE 52-bit. Fedora
and SuSE-based distros then ship a limited set of native 32-bit / PAE
36-bit programs, so those older 32-bit / PAE 36-bit programs then work.
It is _vastly_superior_! Other distros, like Debian, use a chroot
approach, with its positives and negatives.

_Both_ Linux approaches are _better_ than Windows XP x64. And from what
I've seen of Vista so far, the problem is _not_ solved with it either.

In fact, the whole reason for WoW is because Win32 is _not_ "64-bit
clean" like the majority of the GNU world. It's not a solution for the
problem you're thinking of, but a solution for the problem than Win32
can't be ported to 64-bit. Anyone who has talked to MS Office for MacOS
X developers can attest for how 32-bit, data-alignment ignorant,
x86-only Microsoft's codebase is.

Sigh, _please_ understand what I was saying. You obviously can't
recognize that AMD can_not_ solve the issue of programs and libraries
using different memory models.

> And even though Linux, as of today, is mostly "free" of charge the goal of
> it is the same as that of any other. To make a living on Linux, or the
> technology created and proven on it. One would therefore think that the Linux
> community was about eventually making money on Linux, not help make Windows
> the only reasonable platform for desktop users.

Have you _used_ Windows XP x64? It's _worse_ than Linux x86-64!

WoW is not only a _poorly_performing_ solution, it's not very
compatible. And Windows XP x64 is still _largely_ 32-bit -- with all
the associated issues.

Then again, this whole "Longhorn" thing has been a re-hash of the
"Cario" playbook 10 years later. But I won't go there.


--
Bryan J. Smith Professional, technical annoyance
mailto:b.j.smith@xxxxxxxx http://thebs413.blogspot.com
-----------------------------------------------------------
Americans don't get upset because citizens in some foreign
nations can burn the American flag -- Americans get upset
because citizens in those same nations can't burn their own



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