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Despite Aging Design, x86 Still in Charge
An anonymous reader writes "The x86 chip architecture is still kicking, almost 30 years after it was first introduced. A News.com article looks into the reasons why we're not likely to see it phased out any time soon, and the history of a well-known instruction set architecture. 'Every time [there is a dramatic new requirement or change in the marketplace], whether it's the invention of the browser or low-cost network computers that were supposed to make PCs go away, the engineers behind x86 find a way to make it adapt to the situation. Is that a problem? Critics say x86 is saddled with the burden of supporting outdated features and software, and that improvements in energy efficiency and software development have been sacrificed to its legacy. And a comedian would say it all depends on what you think about disco.'"
I'm going to go with:
Did I miss anything?
If you disagree, post your argument. (-1, Overrated) isn't your personal censorship tool for views you don't like.
The X86 ISA is a mess. It is a total pig. It is short on registers and it was just an unpleasant ISA to use from day one.
The problem is that it is a bloody fast and cheap pig that runs a ton of software and has billions or trillions of dollars invested in keeping it useful. I am afraid we are stuck with it. At least the X86-64 is a little better.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
The x86 instruction set will be retired in the same year as the QWERTY keyboard layout.
Just like the four stroke engine. It's not the best one, it can be largely enhanced and made better, but it's still here.
And just like the four stroke engine, modern engines just burn gasoline and push car forward. This is where the similarity with the original engines end.
Maybe Computers will never be as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]
Yes, the instruction set is old, but, it does still work. As a consumer, why should I have to re-invest in software that I purchased and does the job, just becuase my hardware failed, or faster hardware becomes available and I upgrade. Apple bit that one some time ago. Last year, I had an investment of $4000.00 in software when Intel came out with a significantly faster part that was dropping in price. Just by upgrading my hardware (cost $800) my invenstment improved significantly. $4800.00 did not justify the upgrade but the low cost of hardware only, did. Also, there was not learning curve involved.
You don't buy a new car just becuase the tires need replaceing (well some people do, but that is rarely the fiscally responsible thing).
If it ain't broke, it doesn't need fixing.
Athiesm is a religion like not collecting stamps is a hobby.
It has been said that people will not change unless something is preceived to be 10 times better. The problem is nothing has been perceived to be that much better, so people stay with what they know.
Paul
If a chipmaker declared its chip could run only software written past some date such as 1990 or 1995, you would see a dramatic decrease in cost and power consumption, Crosby said. The problem is that deep inside Windows is code taken from the MS-DOS operating system of the early 1980s, and that code looks for certain instructions when it boots.
Even new software might (and often does) use the so-called old instructions. If you want to completely redesign the hardware you would also have to completely rewrite the software from scratch as you would not be able to rely on previously written code and libraries. This is simply not feasible on a global scale...
09 f9 11 02 9d 74 e3 5b d8 41 56 c5 63
And since the 386 consisted of 275000 transistors while modern cpus have more than 200 millions transistors the cost/waste of backwards compability with the 386 is very little.
4. Price / performance. A segment the x86 have done well in.
:D
5. Security. Will my x86 progs be supported in 20 years? The answer: yes.
6. Availability. Hmm... Intel, I'd like to 1 000 000 CPUs. Intel: Sure thing.
7. Good will. What should we buy, Intel or PPC. PPC? What's that? Go Intel! Yes boss. (Just look how far Itanium got on Intel's name, alone.)
Computer manufacturers have tried making non-compatible machines. Commodore 64, VIC 20, Coleco Adam, Atari ST. They all had their place in time and their niche in the market before fading out.
Something they all had in common, though, is that they sold better than IBM's mostly-compatible PCjr. I attribute that difference to software and compatibility problems. Because of BIOS differences, a number of programs written for the PC couldn't run on the PCjr. That led to a fragmentation of shelf space at software retailers and confusion among retail customers, and led to customers avoiding the platform in favor of easier-to-understand options.
I would expect something similar to happen if Intel, AMD, or anyone else started making mostly-compatible x86 processors. It wouldn't sell unless all of the software people are used to running still worked. Sure, someone could take Transmeta's approach and emulate little-used functionality in firmware rather than continuing to implement everything in silicon, but it all pretty much needs to keep working, so why bother?
Seriously, why would anyone undertake the effort and expense needed to slim-down x86 processors when the potential gains are small and the market risk is pretty huge? No chip manufacturer wants to replace the math-challenged Pentium as the most recent mass-market processor to demonstrably not work right.
Pundits and nerds can talk all they want about why the x86 architecture should be put out to pasture, but it won't happen until a successor is available that can run Windows, OSX, and virtually all current software titles at acceptable speeds. At that seems pretty unlikely to happen on anything other than yet another generation of x86 chips.
And the Playstation 3, and the Wii, and your fridge...
If free software ever goes truly mainstream, and the stacks people use are free from top to bottom, lock in goes away in general. Even hardware lock in.
A couple of years ago, I was shifting some stuff around and I needed to clean off my main desktop machine, an x86 box. I installed the same linux distro on a G4 mac and just copied my home directory over. Everything was exactly the same -- my browser bookmarks and stored passwords, my email, my office docs, etc.
A lot of people take Apple's jump from PowerPC to x86 as a sign that x86 is unstoppable. But I'd argue that the comparative ease with which the migration took place shows how weak processor lock in is becoming. The shift from PPC to x86 was nothing compared to the jump from MacOS Classic to OS X.
The real reason x86 won't go away any time soon is that MS has decided that's the only thing it's going to support, and MS powers most of the computers in the world. Windows is closed, so MS's decision on this is final, and impossible to appeal.
As part of an operating systems course I am currently taking, we watched a video of a presenter from Intel who lectured on the changes associated with the Itanium processor. In his presentation (see the video at http://online.stanford.edu/courses/ee380/040218-ee 380-100.asx), he pointed out that Intel has gone from having one or two major ideas to drive chip design to having fifteen or twenty minor ideas that they can cram in. The thinking is that if they can amass enough of these "little ideas" together, they can probably cobble together enough performance enhancement to justify production and sales of these chips. Part of the issue is that, as the author of this article also admits, there is currently no "big ideas" coming around the bend in terms of truly revolutionary performance increase.
The problem, though, is that when you introduce many smaller features, you cannot always anticipate how these features will interact with one another. This is why it is counterintuitive to many people that "new and improved" is not always so, and that you actually risk introducing bugs into the design more subtle than you can detect. That, combined with the continuing support for legacy code, means that complexity (and power consumption) goes through the roof with each iteration. While it is a testament of the robustness and versatility of the x86 architecture that it has survived thus far, one could argue that the architecture *had* to survive because we couldn't come up with the next paradigm shift.
The good news is that there are solutions to this situation. The bad news is that all of the solutions involve massive change in the way the software industry clings to the tried-and-true, or truly revolutionary innovation in chip re-architecture, or billions of dollars, etc. As the article points out, experience with EPIC has demonstrated how NOT to introduce a completely new architecture. There is no easy way out, but there are several possible paths.
We lose the X86 when another processor comes along that is cheaper, 10x more powerful, and runs all X86 software at the speed that the users consider to be the same as a PC. Until then we keep the X86. Simple as that. Next tech issue, please.
So I took a walk this evening, actually while visiting family. We cruise on past this house in a nearby neighborhood and then stop, because I've backtracked. Next to the trash can is a Dell computer. I think, how bad can it be? And take it home. Older processor, dead hard drive, monitor with a bad cap causing intermittent screwups. The only part not fixed is the monitor, but I dropped in an old IDE drive and it's a perfect FreeBSD machine. Heck, if I had the bandwidth at home, I'd serve my website off of it.
The Linux box came from three or four older computers, two of which belonged to me, combined in the least-junky case I could find. I'm still not certain of which distro will be "final" on it, but I'm trying Ubuntu now. This machine gets re-imaged at least once a week, because it's the "beater" box for experiments.
I've also got a Windows XP machine that I love dearly. It's an Intel board, a 2.4ghz P4, some other stuff I forgot. I put it together for $600 and it's more stable than the Windows machines my neighbors bought from Dell. I have no plans to upgrade to Vista for another two or three years, for the largest part because I don't want to buy the hardware.
Life rewards intelligence if you're willing to apply it. Is this hacking, best practices, or common sense? I also get free jalapeno peppers from a very small garden, if I remember to water it. No "corporate chilis" for me. Linus would be proud.
technical writing / development
What's wrong with Vista?
I'll tell you exactly what's wrong with Vista. If you, like many averages shmoes around the world, are in the market for a new PC, you're stuck with Vista. Nothing necessarily wrong with that, except that the shmoe will, as usual, get a $500 dell or a $300 Emachines. Why the hell is he going to spend a grand or more on a PC? Of course, these are pitiful little Duron/Celeron boxes with way too little RAM, lots of bloatware for extra sluggishness, and of course lowest-bidder parts.
So he'll take that PC home, fire it up, and be pretty much instantly pissed. Not only is it slow and sluggish as hell, but this time he has to contend with a lot of new features that he has no clue or experience about. Depending on his patience, he'll plug away for a day or a few, but eventually he'll call me, or someone like me.
Now, this is the important part: He's used to XP. He's used to an OS, that while sucky, worked well enough for him, was relatively speedy, so why can't he just have that? Why does he have to have something replaced that worked just to put up with this shit?
So I will perfrom a downgrade, and I'll happily use a pirated copy to do it, too. As far as I'm concerned, he paid for the OS already, I couldn't give a crap about specific licenses for specific machines. This guy just wants to get on with his life, and that is the service I provide.
Did my first downgrade a couple of days ago, and I expect to be doing several more this year.
Now I know you'll all be yelling about getting sufficient RAM for his machine, going in and cutting some of the bloat instead of resorting to piracy for the backwards step, but if you're going to say all that, it's obvious you don't do a lot of house calls.
Oh, and before I get modded into oblivion by the MS fanboys, look into your hearts. You know I'm right.
Linux, you magnificent bastard, I read the fucking manual!
Because they co-developed the Itanium with Intel. It didn't make sense for them to push their old architecture when they spent a bunch of money to develop a new one for the same market segment. That's why.
The real problem with the Itanium is that it came out a few years too late and the x86 emulation hardware was designed to be on par with the chips that were going to come out at the scheduled release time.
If Bush wants to kill the terrorists, he should jump off a cliff.
The Instruction Set of a processor architecture with so many resources available to it doesn't really matter, so long as it isn't utterly and completely braindead. X86 isn't braindead enough to qualify... if you had an intercal instruction set or an One Instruction Set Computer it might.
You really want to do several things to get performance out of an instruction stream -- register renaming, instruction manipulation (breaking them apart or joining them together or changing them into other instructions), elimination of some bad instruction choices, and a host of other things. You would want to do these things even on a "clean" ISA like Alpha or PPC or MIPS. And if you are doing them, the x86 instruction set suddenly becomes much less of a problem. There are even advantages: the code size on x86 tends to be better than a 32-bits-per-instruction architecture.
Instruction sets are languages with exact meanings. Which means that you can precisely translate from one instruction set to another. And, as it turns out, you can do it fairly easily and efficiently. Which is why Transmeta did pretty well. Which is why Apple's rosetta and Java JIT compilers work (and Alpha FX32 before that). Which is why AMD and Intel are right there at the top of the performance curve with x86-style instruction sets, because it JUST DOESN'T MATTER THAT MUCH.
Why didn't Transmeta kick more butt? Because they didn't have the economies of scale that AMD and Intel have. Because they didn't have the design resources that AMD and intel have. Because AMD and Intel had better-tuned processes faster than TSMC or whoever was fabbing Transmeta's chips. THOSE are the most important things, not the instruction set that you have on disk.
Now a good ISA can help in many ways: SIMD instructions really help to point out data level parallelism. More registers helps a wee bit to prevent unnecessary work done around the stack for correctness. You can get rid of a bit of logic if you can execute without translation. But these things can either be added to x86 (SSE/x86-64) or aren't expensive enough to be worth it on a 100 sq mm, >50W processor. Maybe in an embedded, low-power processor.
-- Erich
Slashdot reader since 1997
This is the same idiotic argument as always. They don't even try to change it up a little bit...
The architectural limitations of x86 were probably true up through the Pentium1 days. After the introduction of Intel's P6, and AMD's K6, everything changed. At that point, x86 was no longer the clumsy CISC snail it used-to be. At that point, and from then on, the fierce competition between Intel and AMD has pushed x86 ahead of every other architecture. Others like Alpha held on to the pure performance crown for a few years to come, but they did so by embracing much higher power consumption. These days, new x86 CPUs are falling in power consumption, not rising. And AMD's Geode CPUs can give you a good performing x86 CPU for embedded systems, OLPC, and anything else, in under 1W. There's really nothing else that is lower power, which still performs as well...
These days, x86 is more than competitive with everything else in sheer performance, performance-per-watt figures, and far ahead in performance per dollar. One at a time, nearly all the limitations of the x86 architecture, that were so often paraded out by competitors, have been worked around. It's most other architectures which were crippled, in that their short-sighted design was only really good in one area, and they only became popular because x86 wasn't quite there at the time. Meanwhile, x86 continued to develop, addressing those shortcomings, and the others did not. The only competitors these days are Power and SPARC, and the two highest-profile companies using them have long since come around, and started selling x86 themselves.
Backwards compatibility is only the smallest of reasons that x86 is still around. How many Linux/BSD users continue to buy x86 systems, even though they would hardly notice an underlying architecture change? How many super-computing clusters are x86-based? It's only the Windows world that needs x86 compatibility, and though that's about 90% of the market, the other 10% use x86 anyhow.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Why does he have to have something replaced that worked just to put up with this shit?
Shhh! If everybody sold good stuff with decent specs and security enabled, you'd be out of business and serving me my lunch. (joking, of course).
Oh, and before I get modded into oblivion by the MS fanboys, look into your hearts. You know I'm right.
Who are you, Darth Vader? Search your feelings, Bill...
> Now, this is the important part: He's used to XP. He's used to an OS, that while sucky, worked well enough for him, was relatively speedy, so why can't he just have that? Why does he have to have something replaced that worked just to put up with this shit?
If instead of giving up after a day, he had tried it for a week or a month, he would have found out how great everything is. Then in a few months he would be used to it and if you try to make him downgrade to XP he will cry.
There are many great features in Vista, but you have to try it for yourself.
I'll probably be modded down for this...
> Oh, and before I get modded into oblivion by the MS fanboys,
For gods sakes, express a point of view and STOP FUCKING WHINING ABOUT MODERATION.
Seriously. Even if you ARE modded down, it doesn't make you some kind of martyr.
Done with slashdot, done with nerds, getting a life.
Sometimes it's support and marketing that make all the difference. Way back when, IBM introduced a new computer called System /360. It was crude compared
to a lot of its competition, but they knew how to sell them, and they
supported them well. IBM went on the rule the mainframe world. Their
competition are now footnotes in history books.
One of IBM's competitors gave us the phrase "Sullen but unrebellious" to describe how much money must be spent looking after customers.
I play with Linux on UltraSPARC (Sun Ultra 5) and StrongARM (gumstix) but am typing this on an x86 Slackware box. Does this mean I too have sold out? :-)
...laura
Low Slashdot-ID? That whippersnapper? Kids today!
My experiences with Alphas were universally bad. The Unix they ran was a flaky bitch, and in any given cluster you were guaranteed to have a few of the machine go during a long computation. Then again, they were expensive.
They were quite zippy though.
Would it be possible to make a legacy free x86 chip? i.e. remove from the processor die real, unreal, VM86, and 16-bit protect modes as well as all traces of the ISA bus, the BIOS, and anything else you can think of? Porting *NIX and Windows to this new platform architecture would be effortless and it would not change userland compatibility.
We don't need to support 30 years of backwards compatibility!
The x86 instruction set is a surprisingly good way to build a computer. The reasons aren't obvious.
First, the original x86 was a huge pain, with that stupid segmented memory arrangement. But IA-32 was better and cleaner; at last there was a flat 32-bit address space. (Yes, there's a segmented 48-bit mode, and Linux even supports it, but at least apps see a flat address space.) AMD-64 is even more regular; the segmented memory stuff is completely gone in 64 bit mode. So there is progress.
RISC architectures could yield simple machines that could execute one simple fixed-width instruction per clock cycle. The early DEC Alphas, the MIPS machines, and early IBM Power chips are examples of straightforward RISC machines. This looked like a big win. The ALU was simple, design teams were small (one midrange MIPS CPU was designed by about six people), and debugging wasn't hard. RISC looked like the future around 1990.
What really changed everything was advanced superscalar architecture. The Pentium Pro, which could execute significantly more than one instruction per clock, changed everything. The complexity was appallingly high, far beyond that of supercomputers. The design teams required were huge; Intel peaked somewhere around 3000 people on that project. But it worked. All the clever stuff, like the "retirement unit" actually worked. Even the horrible cases, like code that stored into instructions just ahead of execution, worked. It was possible to beat the RISC machines without changing the software.
The Pentium Pro was a bit ahead of the available fab technology. It required a multi-chip module, and was expensive to make. But soon fab caught up with architecture, and the result was the Pentium II and III, which delivered this technology to the masses. Then AMD figured out how to do superscalar x86, too, using different approaches than Intel had taken.
The RISC CPUs went superscalar too. But they lost simplicity when they did. One of the big RISC ideas was to have many, many programmer-visible registers and do as much as possible register-to-register. But superscalar technology used register renaming, where the CPU has more internal registers than the programmer sees. The effect is that references to locations near the top of the stack are as efficient as register references. Once the CPU has that capability, all those programmer-visible registers don't help performance.
Making all the instructions the same size, as in most RISC machines, leads to code bloat. Look at RISC code in hex, and you'll see that the middle third of most instructions is zero. Not only does this eat up RAM, it eats up memory and cache bandwidth, which is today's scarce resource. Fixed size instructions simplify instruction decode, but that doesn't really affect performance all that much. So x86, which is a rather compact code representation, actually turns out to be useful.
Seriously you must be new here for the "I'll get moderated down for this but..." trick is one of the PRIME Karma Whoring mantras. Simply by inserting it into your statement you can not only be granted immunity to downmodding by fanboys but you just might get some positive modding by the choir to whom you are a preachin'. Sadly it is also needed in this day and age of the rabid fanboy as sort of a garlic/crucifix/holy water shield agaunst said fanboys simply to keep your karma at a decent level. I know, I post this AC since my karma has been terrible for over 6 years now because of an incident with some Mac fanboys. I've never been modded badly since and the good mods I did get have never restored my karma to a positive level. Had I simply added "The Mac asshats will probably mod me down for this but..." I would probably have my perfect karma that I did so long ago. So that's my pitiful story...mod me down if you must ;)
What MS needs to do is, on vista install, give users a choice of a theme, the normal vista one, or the XP one. Letting them start with the XP one will give them time to get used to the new features while in a familiar interface. Then when they're ready, they can make the theme switch to the default.
Sure, you can throw them in the deep end and hope they swim, but given the odds that they might drown and become an anti-MS advocate for the rest of their lives is a big gamble, when you can just ease them in right from the start.
I'm not say there isn't transition help out there, tutorials (online, built-in), books, but average users don't want to go through all that (even though they should).
-Tony