Introduction to 64-bit Computing and x86-64

James writes "Ars Technica has an article up explaining 64-bit computing from the x86 angle, specifically from the angle of AMD's Hammer. The article explains the details in that usual Ars style, and I found it very useful for thinking about what kinds of applications I may want to put to the test on one of these when we get a box in the office. Even non-x86 freaks may appreciate this, since it breaks down some of the basic advantages of 64-bit computing, and just who can expect to see gains in the near future."

Comments

Re:Mix code in long mode?

[CoolVibe]

Well, the industry can always revert to what Apple did if it isn't possible. Make "Fat" executables. ia-64, ia-32 and x86-64 in one executable. Sure, the binaries will be bigger, but with harddisk prices nowadays I don't believe disk space is really an issue :)

Will Microsoft survive the 64-Bit transition?

[RoLi]

The 64-Bit transition comes with a lot things, all bad for Microsoft:

• For the first time in computing history AMD and Intel no longer see Microsoft as the sole software provider. Both Intel and AMD support Linux from day 1 on their 64-chips. I repeat: That did not happen before. So far, Linux was never available on a chip's introduction.
• On Operon and Itanium, Linux is available before Windows.
• In the first 1 or 2 years, 64-chips will be mainly used on servers, where Linux is already strong.
• To use the additional features/registers, a recompile is neccessary - OSS will use those features right away, while CSS vendors will take quite some time to release a 64-Bit version and will probably want some money for the upgrade.
• The traditional Windows-on-servers customer is a very conservative market segment not likely to jump on the 64-Bit bandwagon very early.

To summarize, Microsoft might run into a chicken-and-egg problem on 64-Bits: Nobody runs Windows on 64-Bits because it's not faster -> Nobody makes Win64 software -> Nobody runs Windows on 64-Bits.

Add into that the fact that Microsoft is traditionally very incompetent and slow when it comes to adopting new architectures and you get the idea.

I think that Microsoft will lose the majority of their server marketshare and a large chunk of their desktop marketshare during that transition. Simple market inertia will prevent Microsoft to be thrown out of the desktop market, but because of the 64-Bit transition, the Linux desktop market might finally gain critical mass and endanger the Windows domination in the long term.

Re:Will Microsoft survive the 64-Bit transition?

[RoLi]

After all, Microsoft HAS developed a version of Windows XP Professional that works on the Itanium CPU in IA-64 mode, for gosh sakes!

Well, although I have never seen a review about that, never seen a Wintel64 system on sale and don't know what dirty hacks and workarounds are in the package, let's assume that's true.

Now look at my post again: All the points I made are still valid, the most important one being that Linux is being supported right from the start for the first time.

I'm sure that Microsoft is right now working a version of Windows XP Home/Professional that works on the AMD Athlon64/Opteron CPU's in x86-64 native mode

While I'm also sure that they are working on it, I'm not about their ability to ship a working product on time. On the other side, SuSE has already successfully ported Linux to mainframes for IBM (something I don't think MS could do with Windows in a timely manner) and they are now porting Linux to Opteron - or better have already ported it as Beta-systems are already out there. - Where is the Windows-Operon Beta? I don's see it.

In case you forgot, Microsoft was YEARS late in finally adequately supporting 32-Bit (actually, Intel was already quite angry at MS that their chips were still used in 16-Bit mode almost exclusively for so long). Of course by that time, there was no alternative, so Microsoft got away with their incompetence, but now there is not only an alternative, it is also supported officially by AMD and Intel.

64-Bit: The "Torque" of a Processor?

[Spencerian]

I'm not an engineer.

What I got from this article (well written, BTW) is that 64-bit processors provide more processing power--a concept different from speed. For instance, a Porsche can fly down the highway, but its engine has insufficent power to tow a 5th wheel RV. A Mack truck isn't speedy, but has a strong engine that can tow the heaviest loads up the same speed--more work is performed.

That would be why Apple's PowerPCs are still in the running, despite their clock slowness. They are falling behind fast as, after a point, speed does matter, in combination with improved processor power in the latest 32-bit Pentiums, and certainly the Xeon. Vector processing, such as Altivec, helps keep Apple competitive with their current chips--just barely. Many in the PC community await AMD's offering while IBM works on blending its POWER chip technology into a 64-bit PowerPC, with Altivec.

Imagine making the Porsche's engine more powerful but maintaining its speed advantage so it can haul ass as well as tow. Add nitro for extra ooompf (vector processing) and you have a dream machine. That's why it seems that 64-bit apps and processors seem to be such a holy grail.

That's my take on it. Clarification is always appreciated.

PPC

[Duncan3]

"Should Apple move from 32-bit PPC to 64-bit PPC, Mac users should not expect the same kinds of performance gains that x86 software sees from the jump to x86-64. 64-bit PPC gives you larger integers and more memory, and that's about it. There are no extra registers, no cleaned up addressing scheme, etc."

Well yea, they already have more then 0 general purpose registers, and a flat memory space, like every other chip besides x86 has had for the last 20 years now. The embedded chips I've used on projects that cost $7 a piece even have more registers then x86 does.

64bit is about the memory, and using that memory, plain and simple. x86 just happens to be using this as a chance to catch up with the cutting edge concepts of the 1980s.

As for x86 needs to die once and for all, it's hacked, hacked again, and hacked yet again. x86 was and is a 16bit system. And now AMD wants to hack it yet again. Can anyone doubt that 80% of the silicon is for supporting legacy apps at this point? Are people that damn lazy they can't type 'make' on a new system? It's not like anyone uses "int" anymore and assumes it's N bits long.