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AMD's 64-Bit Chip
EyesWideOpen writes "AMD is set to release a 64-bit chip early next year which will be completely backwards compatible with the Athlon line. The current 64-bit offering from Intel, Itanium, is an entirely new chip that has no backwards compatibility with its x86 line of chips (from the 8080 chip to the Pentium IV) and is designed only for high end servers. AMD's solution to this problem is the Opteron chip (product info) which will be in servers, desktops and laptops. Here is a wired article."
What's the point of making something that is unsupported by a large chunk of today's software
Because you end up with a CPU that has layers of compatibility upon layers of compatiblity.
you'll have real mode, protected mode and now probably something like 64 bit mode.
imho it's better to get rid off all the old junk and start over once in a while.
Hmm, but you don't expect your DVD player to play your VHS videocassettes?
Backwards compatibility is fine where practical, but sometimes the past needs to be buried. Who would buy a computer now with a punch card reader? Or a 5.25" floppy drive?
people complain about slashdot rerunning stories. have you looked in the newpaper recently? There are full of repetitions and dupilicates, sometimes much more frequently. How many times have you seen violence in the middle east or northern ireland? How many times can you read about some crappy Martin Lawrence movie? All the slashdot editors are doing is trying to keep up with the newspapers.
> imho it's better to get rid off all the old junk and start over once in a while.
Unless of course you've got an installed base somewhere in the billions, 20 years worth of compiler optimization, a factor of, what 100, more people that know the assembly language, etc. And it doesn't help if good compilers won't exist by the time your chip comes out. And if the internal interface teams have difficulty communicating, you're going to be late, hot, slow, and over-complicated.
Starting over is nice from a design perspective, especially because it feeds the urge for creativity that most engineers have. Unfortunately, that do-over is not always executed well, and it turns out to be a little underwhelming, just like Itanium.
Fight the urge to think that all new things are good. Please.
Outside of a dog, a book is a man's best friend. Inside a dog, its too dark to read.
Hmm, but you don't expect your DVD player to play your VHS videocassettes?
Actually, I do, and so do a lot of other people, apparently, which is why I can go to K-Mart or wherever and pick up a player that does DVD and VHS for under $200.
Most people don't buy these because they already have VCRs, and there's little problem using both. However, most people would be really pissed off if you told them that if they bought a DVD player they would no longer be able to watch their VHS tapes.
Itanium sales reflect that fact. Regardless of technical merit, lack of backwards compatability will kill Itanium.
Under capitalism man exploits man. Under communism it's the other way around.
Hmm, but you don't expect your DVD player to play your VHS videocassettes?
I would if they were in the same media type. Just like that new holo-storage announce; they said the drives will be compatiable with CDs and DVDs.
Backwards compatibility is fine where practical, but sometimes the past needs to be buried. Who would buy a computer now with a punch card reader? Or a 5.25" floppy drive?
No neither one. But I see nothing bad with a 64bit x86. If all I wanted was a 64bit system, why pay Intels high prices when I can go Sparc cheaper? If there is no compat, there is no reason to stay Intel.
I don't think anyone's ever said that the Itanium won't run x86 code--just that it does so very, very poorly.
Perl - $Just @when->$you ${thought} s/yn/tax/ &couldn\'t %get $worse;
The Mac shows how a great system with all the best features can not be worth a damn if they don't have the products to back it up. Think of the tens of thousands, the hundreds of thousands, of small 32 bit programs are out on download.com right now. You can't use one of them on the itaniam. No kazaa, no winamp, no aim, no small shareware/freeware apps, and no GAMES!!! If Intel thinks they are going to get a desktop switch over to 64 bit in the next two years b/c they have a faster chip then they must have accidently hired some old Apple employees.
:)
And I have no clue if the mac OS is more stable, faster, etc. But I'm just going from what mac people tell me
My computer doesn't even come with a 3.25" floppy drive or serial ports or hmmm... that's about it, it has everything else, oh wait no PS/2 ports either or 9 pin or serial bus... it doesn't even come with Windows! Talk about a machine of the future... ah I love my Mac.
A fool throws a stone into a well and a thousand sages can not remove it.
I keep seeing blah blah 20 years of legacy bullcrap.
The itanium will emulate a 20 year old CPU with no problem.
The real difference is the last 5 or fewer years, which is still a big chunk, but old terminal software etc. will run on a non x86 chip without problems.
steve snyder
Vote Quimby.
A properly designed 64-bit CPU does not need to 'run slower' to run 32-bit apps. AMD came up with a simple solution to the 32-bit limitations of X86 code: they added a new 'mode' to the processor to run 64-bit binaries. when this mode bit is set (similar to the old Real and and Protected modes of X86 chips), the chip utilizies the full 64-bit-wide pathways for data and cacluations, when this bit is not set, only the lower (or is it upper? AMD isn't saying...) 32-bits of the pathways are used. The same exact logic units are used for all 32-bit and 64-bit calculations, only the bit-depth precision changes. Thus if it takes an ADD instruction 16 cycles to add two registers and store the results in a third register, it takes 16 cycles reguardless fo whcih mode the processor is in. Of course, AMD also added an extra 8 registers for use in 64-bit mode... very useful.
The itantium does not get the majority of it's speed from being 64-bit - this is a common mistake people make. It has a _very_ different design and instruction set - EPIC - which places the burden of parallel instruction determiniation on the compiler. Basicly, they used the oldest software refactoring trick in the book, but on the whole processor design: they examined the amount of time spent executing, and looked for the bigest runtime performance-hit that could be moved from a O(n) to a O(1) penalty by simply moving the calculation. In this case, modern processors spend a great deal of time trying to handle multiple instructions at once, which may or may not be parralellizable (is that a word?) - thus the processor has to figure out, on the fly (in a P4, for example), if it can execute the next four add instructions in parallel, or if they are interdependant and cannot... By placing the burden of parellelism determination and instruction scheduling on the compiler, intel made the compiler writer's job much harder, but at the benefit of increased performance.
Oh, and most PDA processors are much more traditional, and thus don't require complex compilers like the itanium, so actually porting a compiler (or an assembly-lang app) to a PDA from x86(32-bit) is easier than creating one for the EPIC architecture.
And yes, I know the above is an oversimplification, and Intel and AMD both did a lot more, in a lot more detail, on thier 64-bit chips.
Oh, and I think the next few iterations of itaniums _will_ beat the AMD 64-bit chip on bechmarks. But not by a landslide.... And with the differences in price (EPIC chips are Expensive... capital E) the AMD chips will win the hearts of many and be the performance-price ratio king. And who wants to pay 3 times as much for 20% more performance?
man is machine
That's very true, Apple couldn't have done it without developer support. Is Microsoft going to provide a version of Windows that'll run on Itanium while also allowing you to run your old 32-bit Windows apps? Will Itanium run them fast enough to even make this feasible?
I think the answer to the first question is most likely YES, but the answer to the second question, from what I've read, is not quite so clear.
Back in the day, Alpha had Windows NT and an emulation layer that would let you run x86 applications on it. It seems like that's the closest equivalent to the 68K migration that Apple went through. There might have been a lot of external reasons why Alpha failed, but it seems to me that in the x86 world there isn't enough support from all of the different players to make a migration possible. Of course, that's just my opinion, and maybe Intel, Microsoft, and all of the other companies out there will manage to get us all upgraded to Itanium, and do it as smoothly as Apple did.
If a tree fell on a florist, and nobody was around to hear it, would he make a noise?
If you want a "fresh" architecture that isn't full of old junk, buy an Alpha. Or for that matter a MIPS, SPARC, or Power4. All of which are 64-bit and have either always been 64-bit, or at least had their original 32-bit designs planned around 64-bit expansions.
Personally, I think it's amazing how much old crap has been piled onto x86. It's really remarkable it runs at all, and it's even fast! I used to turn up my nose to the x86 given how they piled all the 32-bit extensions on the old 16-bit core. It's really a travesty. And the actual instruction set and register set looks like a damn train wreck compared to MIPS or PPC. But they are soooo cheap I eventually got over it, and just try to avoid thinking about any level lower than 'C' now so I don't go insane.
The vast majority of the old cruft in the X86 architecture that nobody uses any more has been demoted into microcode or other non-optimized crevices. Ever since the Pentium came out, good programmers and compilers have been using an almost RISC-like subset of the X86's myriad possible instructions, operands and addressing modes. IOW, all that old stuff really doesn't slow things down in the real world.
Anyway, recent CPUs have been transforming X86 instructions on-the-fly into bizarre internal parallelized architectures anyway. This hidden logic is an order of magnitude more complex than what is visible in the X86 instruction spec. The implementers are free to completely redo the hidden stuff with every new generation of X86 chip.
"The statement: "...is an entirely new chip that has no backwards compatibility with its x86 line of chips.." on the front page is simply not true.
"
Bullshit. Itanium is as compatible with x86 as my Athlon is compatible with the processors used in the NES, Nintendo 64, Atari 2600, Game Boy, Sega, and Commodore 64.
Tim
Omnia vestra castrorum habetur nobis.
That's funny on so many levels I don't know where to begin.
If you wanna get rich, you know that payback is a bitch
So much cluelessness, so little time...
The Opteron is radically different to processors from the 8086 up to the original Pentium. It's a super-scalar 64-bit RISC core with hardware translation of x86 (and x86-64) instructions. It's designed as a low-cost 64-bit upgrade to the Athlon; the Opteron core is only about 10% bigger than the Athlon core, and will sell in the same price range.
Recent designs like the Athlon and P4 have thoroughly discredited the performance claims of RISC vs. CISC; the x86 translator has little or no impact on the overall performance. It all comes down to details of implementation. (The 8087 FP model is one exception, and SSE2 has now fixed that.)
Itanium is a huge and expensive server chip, designed to compete with other huge and expensive server chips. The original Itanium was also something of a slug, providing fair-to-middling floating point performance and lousy integer performance. The Itanium 2 is supposed to have fixed this, bringing integer performance up to decent levels (though still slower than recent Athlons and P4s) and floating point to match IBM's Power 4. The results are still estimates though, so we'll have to see what actually gets listed on spec.org.
Of course, a dual Athlon or P4 box will be faster and cheaper (if your problem can be multi-threaded).
The Athlon has good FP performance compared to previous x86 chips, but is still limited by the broken 8087 model. Opteron aims to fix this with an extended SSE2 mode.
As for VLIW... This was primarily a *political* decision by Intel. Having spent so much time bagging RISC, they couldn't face bringing out their own RISC chip. So they spent many years and many billions of dollars on the Itanium - which sucked. It ran into the same compiler issues that VLIW has always had. If the performance estimates for Itanium 2 pan out, it would seem that Intel have managed to overcome these problems, or at least provide enough hardware to bulldoze their way through.
And Itanium is NOT by any means a clean architecture. In fact, it's considerably more convoluted than x86. If you want a clean design, look at Alpha or MIPS.
Bottom line: Opteron gives you 64-bit addressing and improved performance, with no penalty for running all your 32-bit applications. And it'll be cheap enough for all but the lowest end of the desktop market.
Itanium 2 gives a big expensive chip for your big expensive servers, and provides decent performance as long as all your applications are recompiled.
> Can you say Macintosh, PowerPC, and MC680x0? I knew you could.
:-)
Amazing how something so condescending could be so wrong.
The Macintosh line could easily move over to PPC from 68k because of one factor and one factor only: the PPC was so much faster than the 68k that 68k apps could run in an emulated 68k environment at decent speeds. And then of course, a huge motivating factor was that the 68k CPUs had reached the end of their useful life and ween't going to be produced at higher speeds.
Fast forward to today, and the situation with Itanium is very different. It can't run x86 applications at near-native speeds. It doesn't offer a compelling upgrade path for users, especially since all their old software and games won't run on it and nothing it offers makes up for that. And then we have AMD's x86-64 Hammer, which offers all the advantages of a 64-bit CPU but with complete backwards compatability with existing 32-bit x86 apps. Many people bitch about the x86 instruction set and the limitations of the architecture, but the fact is instructions sets are nearly meaningless nowadays now that instructions are predecoded into micro-ops and treated as they would be on RISC processors. And the limitations of the x86 architecture are solved in the expanded x86-64 architechture.
Backwards compatability with no discernible performance drawbacks is always preferable to no backwards compatability.
Chasing Amy
(We all chase Amy...)
"The more corrupt the state, the more numerous the laws"-Tacitus