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Design Philosophy of the IBM PowerPC 970
D.J. Hodge writes "Ars Technica has a very detailed article on the PowerPC 970 up that places the CPU in relation to other desktop CPU offerings, including the G4 and the P4. I think this gets at what IBM is doing: 'If the P4 takes a narrow and deep approach to performance and the G4e takes a wide and shallow approach, the 970's approach could be characterized as wide and deep. In other words, the 970 wants to have it both ways: an extremely wide execution core and a 16-stage (integer) pipeline that, while not as deep as the P4's, is nonetheless built for speed.'"
at least according to this amusing article at MacCentral
When will the "projected 2H03 release date" be? I'm not familiar with this term.
Says who? Apple is doing just fine and will be without the crap that is Motorola in a year. I see nothing but a bright future for them with some real hardware.
As evidenced by this review
tcd004
Is this not the chip that was a co venture between apple and ibm? Is this also no the chip that apple intended to use? is this also not the chip thats a 'pc' chip built on RISC? Personally I wanna see what this thing can do before damming it or pronounceing apple dead. Its a year from now, the specs could be COMPLETLY different by then
Jesus saves, everyone else takes full damage from the fireball.
What's the difference between the Power4 and the PowerPC 970? As a Mac guy, I've been following all of the rumors and announcements with interest but I keep seeing the PPC970 referred to as a scaled-back version of the Power4.
Why wouldn't Apple go with the Power4 over the PPC970? And I already know that nothing official has been announced by Apple and that this is all probably going to be a lot of sturm und drang signifying nothing, but that's what keeps us Mac guys going I guess.
Some of you may have read an extremely wide execution core and a 16-stage (integer) pipeline in this article's write-up and been extremely confused. I took a few computer architecture courses back in my undergrad days, so I can refresh some of your memories as well as teach basic processor design to those of you who never got to attend a 4-year college and study computer chips in-depth.
... this takes a much shorter amount of time.
Basically, all modern processors are pipelined. This means that they execute various instructions at the same time. Whereas doing a load of wash, waiting for it to finish, putting it into the dryer, waiting to finish, and then folding would take 30 minutes * 3 steps * 3 loads = 4.5 hours, one could PIPELINE such a process, thus removing sequentialism and doing the first load, then while that's drying put the second load into the washer, and so on
This is all a processor really does. It does a FETCH, an INSTRUCTION DECODE, then an EXECUTION, then perhaps a MEMORY READ/WRITE, and then a WRITE BACK, perhaps. So this 16-stage pipeline can have 16 different instructions executed all at the same time, but just in different points of its execution. The example in CAPS above is a 5-stage pipeline that's similar to those in MIPS processors.
Hope this was helpful!
Department of Physics and Atmospheric Science, Dalhousie University, Halifax, N.S., Canada, B3H 3J5
Make the spec scores barely better than currently produced P4s and schedule a release a year from now. Interesting design philosophy.
I recall IBM's PPC boards going for over a grand, which is (to me) far too much. Especially when it was a 'G3' chip.
Even if the new chip is faster, will I be able to buy 2 pentium 4's (5?) for the price of it?
Kudos to the Ars team yet again for going deeper into CPU designs than 99% of the populace need to go :)
I think that since this is a 64 bit chip, why not compare it with other 64 bit consumer desktop chips (ie, AMD Clawhammer)? A lot of Intel's questionable moves (12K micro-ops instruction cache?) for the P4 were obviously not copied by AMD, and x86-64 seems to be the 64 bit desktop chip of the future.
Make sure everyone's vote counts: Verified Voting
The PowerPC 970 has other potential customers as well, though, not the least of which is IBM itself who, with its large investments in Linux, would love to see a high-performance, 970-based 4-way or 8-way SMP Linux desktop workstation halt the steady flow of former 64-bit *NIX workstation users who began switching to Wintel hardware in the late 90's.
Before all my fellow Mac users start A) thinking about going to Linux B) drooling C) wondering about Darwin or D) some combination of the above, let me remind you that Darwin scales very well. You can now return to your previous state of awe.
PS - How much you want to bet good ol Steve is already having wet dreams about doing the traditional Photoshop test at a Macworld with 4-way SMP?
This chip could be the start of something big in the Linux space as well. Think about it, we are now at a point where a few companies other than Intel are now poised to take the center stage in the next gen workstation, most notably AMD, Apple, and now IBM themselves.
While Linux has run on PPC chips for a long time, it is difficult to come upon a G4 chip without paying the "Apple Tax" for the hardware. If IBM steps up to the plate with this chip, which can then run OS X, Mach, Linux, *BSD, (insert other OS'es here), and can be purchased directly or in a package from IBM, we may see a good set of Windows challengers for the desktop and server room. Obviously OS X will still only run on Apple derivatives.
These chips will be big, I guarantee it, and not just for Apple. It will be interesting to see if Microsoft ports Win XP to these chips.
Why would they want to?
Intel and AMD have the x86 market pretty well locked down.
More importantly, why would ANYBODY want to implement the x86 ISA (Instruction Set Architecture or smtn like that). It's the most horrid instruction set in use today.
Some instruction sets can't really be mapped to others easily, and optimizing for good performance with PPC would probably not have good x86 performance anyways.
In Pentiums and Athlons, the instruction set isn't really emulated. It's translated to a smaller instruction set (uops, iops, pick whatever term you like and run with it). However, these smaller sets are still made pretty much specifically to cover the overlying ISA (x86 in this case).
Estimated Power4 scores
P4 scores at SPEC
Estimated Power4 scores:
Est. SPEC INT 937 @ 1.8 GHz
Est. SPEC FP 1051 @ 1.8 GHz
Intel Corporation Intel D850EMVR motherboard (2.8 GHz, Pentium 4 processor):
SPEC INT 1032
SPEC FP 1034
I think Apple will stick with a company that it knows, IBM, since they have been working together for years. It doesn't seem that Apple will just jump ship to the x86 platform. This would also mean redoing the Mac OS X code and optimization (not like they will have to do some anyway, but they will have to do more). It is highly unlike that Apple will go with a heat producing, energy wasting x86 Intel chip.
One of the early planned PPC chips had that idea in mind, by pretty much adding an x86 processor and logic to figure out what instruction set it was getting and where to send it. The idea was that then there would be no barrier to using PPC code - it could run x86 code to replace existing systems and run PPC as well. Thus it would be a transitioning thing.
The x86 world seemed to move faster than the design for this and it fell away. It made more sense to concentrate on PPC stuff rather than try to do PPC and changing x86 stuff. Also, if it ran x86, why should anyone bother to write for PPC?
The difference is Pentiums and Athlons are intended to be x86 family upgrades, while the PPC is not. The PPC 970 is meant as an upgrade to earlier PPCs. One could as well ask why AMD doesn't make an Athlon that can run PPC code.
I don't subscribe to RMS's GNUtopian vision.
Apple will almost certainly go with 970 and not switch to Intel for the following reasons: 1. It is difficult to emulate PowerPC with Intel (although the reverse isn't *that* difficult). Apple would need a PowerPC emulator so that all that software (including OSX software) isn't lost. 2. Apple wants to differentiate itself somewhat from the PC. 3. IBM appears to be moving up after the several years of problems with Motorola. The downside is that by the time a 970 board is out it will definitely be in the middle of the pack relative to the PC world. That means that Apple still will have computers that are more expensive than the PC world and that aren't as fast. Of course I think OSX is sufficiently better than either Linux or WinXP for a workstation that I'll stick with it. But Apple best hope that IBM gets large yields on time and perhaps with better speeds than expected.
I modded him up previously based on your linked comment and after reading his journal about rough mods. I struggled since some of his past posts were pretty weak and a chunk of his friends are trolls, but I decided to try giving him the benefit of the doubt since the post seemed genuine and was interesting. I hope this wasn't just the classic troll attempt to get back to +1.
Did you miss the System Controller present on the Xserve and the new G4s?
As was mentioned in this previous article, Mac has been maintaining a seperate port of MacOS X for x86 in synch with the PPC version... I still remember some promotional material pre-OS X talking about an x86 version of Mac OS X being released that lacked the functionality to run Mac OS Classic apps (I think it was called Blue Box?). ;)
;)
Are they going to jump ship to x86? Not likely if they can help it... but they're keeping the option open. Kind of like how Dr. Evil KNOWS his plans will never fail, but he always has that Big Boy rocket hidden in the back--just in case.
And who ya calling energy wasting? My Palomino keeps my room nice and toasty on those lonely nights and makes great julienne fries!
Maxim: People cannot follow directions.
Increases in truth directly with the length of time spent explaining them
Because they would have to license the x86 architecture from the respective owners. AMD and INTEL have licensing agreements.
Puto
The Revolution Will Not Be Televised
finally they'll see that clock speed does make a difference Clock speed is something Intel uses to bolster their performance claims and give people an excuse to upgrade to the newest model. Clock speed tells very little about the performance of a computer. Look at AMD's athlon. Many reviews like the ones on tom's hardware show that running Windows on a "slower" athlon yeilds better performance than a comparably clocked P4. If you meant that finally, if apple runs on x86, there will be a better benchmark between Windows and MacOS, you would be more accurate. Until that happens you are comparing two different fruits.
0xfeedface
I've been wondering about this also in regards to ECC for RAM. Does the fact that it has built-in error correction mean that the CPU/RAM is actually more prone to errors by design (since they can be corrected? And if so, is there more of a chance for degraded performance?
It is highly unlike[ly] that Apple will go with a heat producing, energy wasting x86 Intel chip.
...because PPC chips completely disobey the laws of physics, producing neither heat, nor "waste energy" (perhaps through the production of heat?). Yes, it is PPC, miracle of modern technology, standing up for the common man against the perils of Thermodynamics!
The other responses to your question have pretty much hit it dead-on. I just wanted to comment that the PowerPC has always been the little brother of the Power architecture used originally in the RS6000 ... and now in almost everything IBM makes - AS400, E9000, etc.
... because of this the migration of everything into one die for the PowerPC was amazing.
;)
The first generations (601, 603/604 and the ?aborted? 620) of the PowerPC line were scaled-back versions of the Power and Power2 architectures respectively [the original Power architecture was mounted on a 3x5 daughter card with 4-5 separate chips [I'll have to go looking for my tech papers] making-up the core
Additionally, IBM has tended to work-out new capabilities -- such as the move to 64-bit and dual cores -- on the larger scale Power architecture, before attempting to stuff it into the smaller PowerPC pacakge [besides, IBM has to keep something to distinguish its pricier iron from the OEMs.
Natty
Maybe the rain Isn't really to blame. So I'll remove the cause, But not the symptom!
i understand that comparing intel and g4's is apples and oranges and that intel uses clock speeds for marketing as well. however, why do you think there is such a huge overclocking market? it's simple: clock speed does make a difference.
you failed to properly spell "genitals".
Why bother.
you hit the wrong checkbox, luz0r
How on earth is anyone supposed to know what this part is going to be priced at? I doubt IBM even has anything resembling a firm idea. The price is going to depend on yields, production quantities and a number of other factors.
-jason m
Sure, clock speed makes a difference, but only on the same chip. The post I was commenting on implied that you could compare the clock speed of an Intel machine to the clock speed of an Apple machine. For such a comparison clock speed is wholly irrelevant.
P.S. My 333Mhz P2 runs great at 400Mhz, but largely because Intel underclocked the identical core to run at 333Mhz. Intel plays up the importance of clock speed, so they do dumb things like underclocking, and multiplyer locking.
0xfeedface
I know that the press believes that Apple is going to grab IBM's chip hot off the presses, but does anybody know anything hard core about Motorola's G5?
make the chip compatible with x86 instructions -- the Hammer does it, why can't the PowerPC chip?
If that's such a great idea, then why isn't it working so well for transmeta?
to further clarify, sometimes the instruction you want to push into the pipeline depends on the result of another instruction that's still in the pipeline. when this happens, you have to basically close the entrance to the pipeline and wait for that instruction to come out of the pipeline before opening it up again. there are ways to minimize this effect, but still you will not see a 16-fold improvement over not having the pipeline.
track7.org has all kinds of interesting stuff!
Looking purely at die size, one can expect manufacturing costs of the p4 and ppc970 as being roughly equal: PowerPC 970 1.8 GHz, 0.13um, 121 mm2, 52 million transitors Pentium 4 2.8 GHz, 0.13um, 131 mm2, 55 million transistors As long as IBM is not using the exotic materials of the power4, then the main advantage Intel has for pricing is that their R&D can be spread over many more chips. What the R&D costs of the ppc 970 are is interesting, especially since IBM is trying to position themselves as a maker of custom chips leveraging their ppc ISA and the experience gained through their big bucks power series.
All this talk about SMP machines coming nicely from this chip (and IBM's supposed workstation/linux aspirations) has me wondering something. Has anyone thought about adding openMP support to gcc? I'd give my eye-teeth for that. (Well, at least my wisdom teeth.)
I already know about OmniMP and OdinMP, but I want openmp natively in the compiler. Anybody know more than me?
You say
*Sigh* The size of a CPU's address/data bus does not reflect a processor's "bitness". 64-bit means that it has a 64-bit word size (as opposed to the 32-bit word size on x86 processors), 64-bit registers, etc. Most 64-bit CPUs don't actually have a 64-bit address bus. Like you said, the Alpha's is 48-bit. This is usually done to keep the pin count down to a sane level (if you need all the physical RAM that a 64-bit address bus would provide, you need something bigger than a desktop CPU). You can expect that as 64-bit chips become more common on the desktop to see somebody introduce a 64-bit CPU that has a 64-bit address bus just so that they can say, "Hey, look, we have a 64-bit address bus, the other guys only have a 48-bit one!" and (like you are trying to do) will insinuate that this means the competition's CPUs aren't "true" 64-bit (even though they are).
I dunno 'bout Macs (I don't know the M68k's "bitness"), but Intel introduced the 386 (their first 32-bit CPU) in 1986. And I certainly don't think the M68k was a RISC processor.
at current prices and projected prices, 512 gigabytes or RAM will barely cost more than a couple of the fastest processors of this type.
Really? I would LOVE to be able to buy 512 gigabytes of RAM for the cost of a couple of fast desktop processors. Don't forget that the PowerPC 970 is meant to be a desktop processor.
So now I have to be wide AND go deep to be competitive?? Damn it...next thing you know the girlfriend will be wanting a faster FPU too....
Wise men say, "Forgiveness is divine, but never pay full price for late pizza."
Why do you keep claiming its 64 bits?
However, as fast and amazing and AMD crushing as this 970 chip is... it only has a 40 bit data bus.
This means you cannot physically ever attach more than 1024 gigabytes of ram to it EVER.
At least in the 1990's and early 1990's some 64 bit risc chips had 48 bits of addressing, not lame 40 bits.
This is considerred a hack by some engineers.
The Power4 is astounding and amazing and will help apple trounce Intel benchmarks (Pentium4 cannot be multiprocessor only expensive xeon and
itanium) but this chip is only 40 bits! The RC5 key benchmark is already over 4 times faster on a mac than on the fastests Pentium 4, and twices as fast as ADM dual processor. Consult rc5 project site if you doubt this.
True, it the 970 has 64 bit integer instructions that only have value in cryptography, and some relevance in some gaming computation, but the chip is
NOT 64 bits in my mind uless it can physically attach to more than 1024 gigabytes of mapped locations.
Heres another "gocha" Apple, like EVERY OTHER OS KNOWN, will steal a bit or two for dividing pci dma space or dividing kernel space
meaning that this chip will only EVER support 512 gigabytes of RAM, ever. Or even 256 GB if they steal two bits instead of one.
at current prices and projected prices, 512 gigabytes or RAM will barely cost more than a couple of the fastest processors of this type.
In linux you cannot have a single application grab and use over 1 gigabyte of GENUINE held and locked RAM, nor in Win2000 regular, nor
WinMe.... but years ago in 1996 normal mac such as the PowerMac 9500 could actually create and USE over 1 gigabyte of ram dedicated to
a single user task.
In 2002, few unix OSses, not even OS X, allow over 1 gigabyte of ram for a single process.
I want Power4 from Sonnet in my mac, not this 970 inadequacy.
But then again I also need a way to cram in 512 gigabyte of RAM for three-dimensional finite difference time domain 3D FDTD, for studying energy for
optics computation of laser circuitry construction.
FDTD NEEDS RAM!!!! real ram... not emulated virtual ram.
Why do fanboys mod stuff like this down? Its all facts and not expressed elsewhere. I restate this because evidently modding is based on popularity contests and not logic sometimes. My original was slammed at -1 as this one is as well probably, even though it is informative and factual.
Because that is where most of the desktop CPU money is going, some of the high end, and frighteningly enough a fair bit of embedded CPU money too.
In short if you can navigate the patent mine field, the brutal competition mine field, and deal with the instruction set making things a royal bitch doing an x86 CPU is a total no-brainer.
Other then needing a whole new decoding front end, and being forced to use a trace cache because decoding multiple instructions in x86 land is very hard... the instruction thing isn't a big deal. Handling the odd-ball 80 bit FP format is. So is emulating all of the trap stuff and the other little odd bits close to the instructions set (like the MMU).
A big pain. But with much of the effort not being where folks think it is!
If the P4 takes a narrow and deep approach to performance and the G4e takes a wide and shallow approach, the 970's approach could be characterized as wide and deep.
Watch it, this is a family website.
When I had the Pentium 4, she complained about its narrowness, but its was great. With the G4 Mac, it was nicely wide, but too short, she would note. I'm sure that with the 970, I can fulfill all her dreams!
// file: mice.h
#include "frickin_lasers.h"
Learn your history... APPLE was first beating wintel.
Apple used 32 bit processors (MC68000) in Lisa in Sept 1982.
It used them again in January 1984 with the Macintosh computer.
The 1982 lisa had windows, scolling, dialogs, fonts, buttons, WYSIWYG text editing with graphics, etc.
The IBM PC in Sept 1982 supported only black and white and used a cassette tape drive standard. It cost 600 dollars and was sold at Sears and had a 4 week backlog of orders. But it was not 32 bits like the Macintosh or Lisa.
the Apple II had 75% of us market and used floppy drives (fast ones), but as you know, the IBM PC eventually supported Lotus 123 and the rest is history. (Apple used VisiCalc and supported Multiplan using a cheap CPM card, as well as Turbo pascal and other cpm products)
Also in March 1987 Apple supported choices from million of colors and 6 simultaneous monitors attached and supported.
The lisa may have been a 680010 for special purposes. It has no TAS (test and set) and other things that the Macintosh lacked, but the Lisa did have multiple hard drives, and a 15 inch hires printer.
Sorry for typing MC68000, the Mac used the 680000 for certain, I think the lisa did but I do not want to be wrong. The Lisa was shown publicly in fall of 1982 though but delayed shipping until special new floppy drive and hard drive issues were all settled in late dec 1982.
Apple OS was generally 8 years ahead of MS in most technologies over the next 15 years. Apples chips were ahead as well for most years too, but economies of scalle and price wars still have not kept the price of a 800 Mhz itanium chip below 7 and a half thousand dollars. (look on Price watch if you doubt me).
Thats why apple does so well in workstation world.
...an extremely wide execution core and a 16-stage (integer) pipeline that, while not as deep as the P4's, is nonetheless built for speed.
:-)
For those not planning to read the article, I wanted to mention the following so you do not get the wrong impression. The speed that the article refers to (of a long integer pipeline, like a 16-stage or like the Pentium IV's 20-stage) is clockspeed, not necessarily actual performance. The P4's super long pipeline, for example, allows it to run at higher clock speeds, but less work gets done in the same number of clock cycles. This is the "braniac" vs "speed demon" philosophy (with a high clock speed but low instructions-per-clock representing "speed demon") and neither is necessarily better than the other (though one is obviously better for the marketing dept.)
Just don't assume that "built for speed" always means "built to be fast" -- a confusing but important distinction.
Computer Science is no more about computers than astronomy is about telescopes. --E. W. Dijkstra
A lot of Intel's questionable moves (12K micro-ops instruction cache?) for the P4 were obviously not copied by AMD, and x86-64 seems to be the 64 bit desktop chip of the future.
The P4 has its flaws, but IMO cacheing decoded instructions isn't one of them. It shortens the pipeline, and paves the way for a true trace cache (cache of decoded basic blocks indexed by entry point; very handy for renaming and scheduling).
My guess is that we're gonna see "Four brains are better than one" right around the time the 970 arrives, and that this time it will make the Mac competetive (unlike the Daystar days).
just my blog and pix
What I really want to know is how much this chip is going to cost. If its cheap for Apple to put 2 or 4 of these in a machine, then how much will it matter that an expensive P4 (P5) out performs it? Hmmm.... The current Wind-Tunnel G4s raised a few eyebrows when it first came out do to the new case design. These things were designed to disapate heat! A HUGE (7 lbs) heat sink w/ matching fan, a small case fan, 2 fans on the power supply, and a ton of ventalation in the back. WAY more cooling that those 2 little G4s require. I think Apple is trying to avoid the fiasco it had with the Sawtooth (1st gen) G4s where they just slapped a G4 onto a G3 mobo. This time around, I believe they're releasing a new mobo first and then put a new proc in it down the road. I've also read stuff in forums suggesting that the power supply for the Wind-Tunnel had way more juice than the system currently demands. Can anyone out there do the math on this? We know how much power the PPC 970 eats. Can we figure out how much heat the Wind-Tunnel case is designed to disapate? What about how much power the power supply is putting? With these numbers, can we figure out how many PPC 970 the Wind-Tunnel case could power and cool? I've been suffering with a 266MHz G3 iMac, and I refuse to upgrade until Apple comes out with a system that really is worth that premium they charge, and a G4 is not it.
I specifically said, "I dunno 'bout Macs..." because I wasn't trying to make a "See? Intel is better than Mac" post. I was just giving the date at which Intel introduced their first 32-bit processor.
And now that you mention it, I do remember reading that the M68k was 32-bit, but it only had a 24-bit address bus, which meant the max. amount of RAM it could physically have was 16 megabytes. Again, I'm not trying to bash anybody, I'm trying to point out that your "64-bit CPUs aren't really 64-bit because they only have a 48-bit address bus" argument is flawed.
Why you went off on the whole Apple vs. Wintel thing is beyond me, but if you want to play ball, OK. For the record, the PC wasn't meant to compete with the Lisa or the Mac, and both of those computers were introduced after the PC. The original IBM PC was a competitor to the Apple II, but more oriented towards business use rather than home use. If you remember, the Apple II also used a cassette tape drive (just like the original PC), but, like the PC's successors, the PC-XT and the PC-AT (all modern PCs are descended from the PC-AT), later had the ability to use floppy drives and hard drives.
The 1982 lisa had windows, scolling, dialogs, fonts, buttons, WYSIWYG text editing with graphics, etc.
Which were all "borrowed" from Xerox PARC. The fact that Apple later whined and bitched about Microsoft "borrowing" those ideas from the Lisa and/or Mac (when Apple themselves had stolen those concepts from somebody else in the first place) is too amusing for words. I can't stomach Bill Gates, but I have just as hard of a time putting up with Steve Jobs ("You stole Windows! It's not fair! We stole it first!").
And as for Mac OS always being 8 years ahead of Windows, well, I'm no lover of Windows, but Windows had preemptive multitasking years before Mac OS (Windows got it in Win95, Mac OS didn't have it until OS X).
the Apple II had 75% of us market
Although I don't have any hard facts, I have a hard time with this. It wasn't like IBM and Apple were the only players in the personal computer market. There was Commodore with their highly successful Commodore 64 computer (not to mention the Commodore PET, VIC-20, and Commodore 128), Sinclair, the TRS-80 (from Tandy and RadioShack IIRC), and a whole host of others.
Who needs L3 cache connectors when you have a 900 mhz system bus? There are only two reasons to have L3 cache: the system is massive multiprocessors system (like the Power4) or the system has a ridiculously slow system bus (like the Motorola G4). The PowerPC 970 has no need for L3 cache because the bus is just that fast. Hell, the bandwidth to the L3 cache on a G4 is only 4.6 Gbps. It is DDR and effectively runs at half the clockspeed just like the main bus on the 970.
IT IS ONLY 40 BITS not 64
Your desire to use address pins (or is it max pinned space per process?) to measure size puts you in a distinct minority. That doesn't make you wrong. But neither does it help make you right in this particular jungle.
Systems whose physical addressing match their claimed "bitness" are probably in the minority.
Some systems provide more physical addressing than register width (later PDP-11s, 8086, S/390), some less (68000, classic CDCs, early POWER). The 970 falls into the less category. Nothing unusual there.
Apple, like EVERY OTHER OS KNOWN, will steal a bit or two
Some bits come from physical addresses, some from virtual addresses. These should be addressed [pun slipped in, sorry] separately. AIX, btw, steals less than one bit. Linux can also be configured to steal less than one bit. (Assertions I can get away with no loss of credibility, since AC's have none to start with.) Were you frightened by a VAX in your formative years?
Why do fanboys mod stuff like this down?
Because we can't figure out why someone who needs 512GB, or 1TB, or more (which is it?) cares that a Linux process is limited to 1GB and not 2GB or 4GB.
and use her Palm and an emulator
Cake or Death? Cake Please!
Yes, there are trolls at K5 and /., and yes they are damn annoying.
But the real problem is the number of arrogant bullshitters who are drawn to internet message boards and obsessively post all day long.
yeah, sure
coz FOUR PPC 970s will be virtually free, won't they? It's not as if these chips ae gonna cost $500 each or anything...
That was classic intercourse!
Actually... I wouldn't mind having that many processors, even ignoring that the Altivec uses single-precision floats rather than doubles.
Sorry, can't resist. Imagine a cluster of PPC970s, each with 4 fast processors and a huge memory bandwidth. Not bad.
-Geoff
-Kevin
Not if they scratch-built their own copy of it, then they'd only have to get copyright licenses to be able to say 'x86'. Think about SAMBA.
40 bit address bus. Not a 40 bit data bus. BIG difference there.
And the 40 bit address bus is most likely a pin packaging limitation. They did not see a need to bring those extra 24 address lines out to the chip package. Internally, it is 64 bit. Much like the venerable MC68000 was 24 bit externally, but 32 bit internally.
But seriously, in the life-span of THIS processor implementation - do you seriously see ANY desktop manufacturer even thinking about putting that much RAM in their CPUs?? Heck 1GB of RAM is not 'standard' yet. Extrapolating w/ Moore's Law, we'll be approaching 40bits in 8 years. Apple will undoubtedly have another chip before then!
If you truly need THAT much physical storage today, you'll need to shell out for a SERIOUSLY large server. IBM's high-end p690 currently maxes out at 256GB. The virtual address space is undoubtedly much higher.
Tom
I ask you good sir, how do you know they are going to be more expensive?
Thanks for random speculation based on no facts whatsoever, it really helps the discussion.
probably closer to $400 for the top of the cutting edge at the begining, with the 1.2g versions being around $270 (lower misfab rates). Prices will go down as this is IBM's competition to "comodity x86" hardware they are forced to use on their blades currently, I wouldn't doubt but within 10 years IBM and AMD will be fighting a price war over the desktop.
Intel seems happy to sit out this round, I'm wondering if they are going to be there next round though.
Ok, apple most likely isn't going to go with Intel CPUs, but one of your reasons is wrong.
Mac OS X binaries are capable of being FAT. They can contain both PPC and Intel instructions. OS X binaries are actually folders which can contain multiple architecture implementations within them. This also applies to the "libraries". Ok, the Framework bundles.
Why don't you just STFU and buy a http://www.sgi.com/visualization/onyx/3000/
One time someone asked me "Will this faster processor help me download quicker or what"
I stared at him and just said "Yes...yes it will"
--Joey
isn't this linked on apple.slashdot.org???
IBM 970 makes us aquadorks drool...
IMHO five minutes of researching a mod decision isn't out of line when a comment is getting a large number of moderations up and down or when half of the replies are from people trying to figure out whether the parent was written by a troll. Providing info to other mods as AC is hardly ruining slashdot, especially if it helps to clarify which posts are accurate and trustworthy.
All 64bit machines are actually narrower, and as long as the architecture is spec'd properly, THERE IS NO REASON A LATER CHIP CAN'T ADD MORE PHYSICAL ADDRESS BITS. See the progression the Dec Alpha went through for example.
For the time window the 970 will be in market, a 1TB address space is huge, and saving some bus lines will be a bigger impact by saving bottom line $ than bragging rights over being able to address ram capacities that no one will use.
If you need to address large ram capacities, you're clearly not in the market the 970 is designed for. While geek bragging rights might be fun, apple would have to be as daft as you are to actually bias the price of their product line to achive it.
Nobody ever said premium Mac systems were cheap. Quad proc Daystars were quite expensive in the day.
I said "competitive", but I meant in performance terms. Price competitiveness is a whole different issue, though as another poster hinted, price/performance might not be as bad as one would think, esp. if IBM isn't plagued by the same fab issues Motorola has come across with the G4 (and history has shown that they probably won't be).
just my blog and pix
Uhh, 40 bits is 1 TERAbyte. Not 1 GB... Yeesh.
It is difficult to emulate PowerPC with Intel (although the reverse isn't *that* difficult).
This seems to be a common myth amongst Mac users, but it's completely bogus. There's nothing magical or mysterious about emulating one 32-bit architecture on another, and writing a PowerPC emulator for the x86 would not be significantly different to writing an x86 emulator for the PowerPC. The fact that Intel CPUs are considerably faster, however, does mean the x86 could in all probability do a better job of emulating the PowerPC than vice-versa.
The main reason for the lack of (modern) Mac emulators is a lack of demand. I mean, virtually anything that runs on a Mac also runs on a PC, so why on earth would any PC user want to emulate a Mac? The reverse is obviously not the case, hence the popularity of PC emulators amongst Mac users.
Apart from the lack of demand, the tricky thing about emulating a Mac is Apple's closed architecture. The PC architecture is open, so it's relatively easy to implement it in software. Although the Mac has imported a lot of open architectures from the PC (e.g. PCI, AGP, USB), the Mac system-board designs are closely guarded by Apple to prevent clones. That's why not even other PowerPC systems (e.g. IBM RS/6000s) can emulate current Macs. If PC or RS/6000 users really wanted to emulate Macs, someone could probably reverse-engineer one, but the simple fact is they don't.
Ignorant rants of this kind get on my nerves. A process in Windows (NT/2000/XP) gets 2GB of address space by default, which can all be backed by physical RAM. With the /3GB switch in the boot.ini, which has been around since NT4 Enterprise Edition, the process address space is increased to 3GB (with the kernel address space correspondingly reduced from 2GB to 1GB). If Linux for some reason can't even back 1GB of the process address space with physical RAM, it must have a really crappy memory manager.
On the hardware side, modern x86 CPUs actually support 64GB of physical memory, but it can't be directly accessed (since the address space is only 4GB), so it's only available via convoluted mechanisms like the Windows PAE APIs (and I think they can only access the full 64GB on Windows 2000 Datacenter -- not that normal PC motherboards/chipsets support it anyway).
Large address space does not have to mean "buy lots of RAM".
It can also mean "lots of virtual memory", or "ability to mmap extremely large files" without any problems at all.
If the P4 takes a narrow and deep approach to performance and the G4e takes a wide and shallow approach, the 970's approach could be characterized as wide and deep
Hey ladies!! My approach could be characterized as wide and deep too.
He painted a unicorn in outer space. I'm askin' ya, what's it breathin'?
What does a poster's history have to do with it? Read his post and decide - if you still can't figure out if it's a troll or not then don't moderate. In this case PS's post is not a troll as it is factually correct (when he is trolling he is a lame watered down knock off of PhysicsGenius). No, in this case he is whoring for karma - if you think this is informative mod it up - if not then don't bother modding it down - mod someone else up instead. Remember the slashdot janitors have an infinite supply of mod points and are not scared to (ab)use them.
--
Reverse outsourcing: it's the future
just after our sun expands to a red giant and swallows the earth and moon.
/.!?
Didn't I see a post about that being emminent? We only have a few million years left. Why waste them on
You can't judge a book by the way it wears its hair.
Yes, the binaries can be "FAT" - but currently not a single one is. IOW all software would have to be recompiled (if that is possible at all).
Lars T.
To the guy who modded me down from perfect to terrible Karma - Apple haters still suck
I see my post has been modded down. This must be because it links to SPEC results which show Macs are somewhat slower than PCs? They are nevertheless good machines, and unfortunately for the modder, sticking ones head into the sand like an ostrich wont speed them up!
You mean like AMD? With more than 20% marketshare and bleeding money? Yeah, right, I know this is just because of their Flash memory business.
Lars T.
To the guy who modded me down from perfect to terrible Karma - Apple haters still suck
The first generations (601, 603/604 and the ?aborted? 620) of the PowerPC line were scaled-back versions of the Power and Power2 architectures respectively [the original Power architecture was mounted on a 3x5 daughter card with 4-5 separate chips [I'll have to go looking for my tech papers] making-up the core ... because of this the migration of everything into one die for the PowerPC was amazing.
The PowerPC 601 was not a scaled back version of the Power series. To say this would imply that they took the design and modified it. In fact, they took the Power instruction set, modified that and then designed the processor to support it for the target markets.
The 64 bit PowerPC 620 was not "aborted" per se (like the PowerPC 615 was), rather IBM decided that its role was filled by the higher clocked 604 series and the then soon-to-come IBM Rochester, MN designed 64 bit PowerPC 630 (aka Power 3).
To verify my claim that the PowerPC 620 was not aborted, Motorola got suckered into manufacturing them for Bull.
If you don't enable HIGHMEM in the Linux kernel, each process is limited to 3 GB, so it steals only 1 GB (wich is less than a bit). If you do, you can have the full 4 GB per process.
Windows only recently (last couple of years) got the ability to work with more than 512Mb, and now they're pissed about another OS only being able address a Terabyte? Talk about yer double-standard...
Windows only recently (last couple of years) got the ability to work with more than 512Mb, and now they're pissed about another OS only being able address a Terabyte? Talk about yer double-standard...
Huh? Windows NT's been around since 1993 (a wee bit longer than 'a couple of years'), and has never had any '512MB limit'. Of course Windows NT/2000/XP supports 4GB of RAM (the max a 32-bit system can directly address), and for a few years has even offered an address-space mode that reduced the kernel address space to 1GB (from the usual 2GB), leaving each process with 3GB. The more expensive server versions also support >4GB RAM (up to the CPU limit of 64GB) through PAE, but only extremely pricey server hardware supports that much RAM, and it can't be directly addressed.
If 64GB RAM and a 3GB process address space (essentially the upper limit for x86 systems) isn't enough, there's Itanium and x86-64.
What ever happened to the IBM released ATX compliant, socket (PPC) motherboard specs? I used to have a link to them, but I can't find it now.
All I remember is that a couple of years ago, IBM released an open resource platform that was a standard ATX implementation for their (at the time) top of the line PPC604 chips.
The thing looked just like an (Intel) board that we've all come to know and love. It had DIMM sockets, a ZIFF based processor socket, PCI bus, AGP video (though for some reason I seem to remember it *not* having USB).
All of these companies (something like six, which is a lot in this type of industry Mainboard wise, right?) jumped on the build about PowerPC motherboards. "It was like several PC component manufactures cried out in agony, and then were suddenly silenced." Because they all, like, just disappeared off the radar.
Did Apple pull some kind of "Don't you dare let them build those motherboards or we'll walk" type of attitude? Because it's just *really* odd that I didn't see a *single* physical computer get built out of all these announced and proposed PowerPC Linux workstation systems.
Anyone know what happened?
"Genius may shine aloof and alone, like a star, but goodness is social, and it takes two men and God to make a Brother."
If IBM can offer the PPC 970 at a good price, then Apple will be able to offer dual processor Powermacs, or perhaps even quad processor Macs. With such a design, it is no longer important for the PPC 970 to best the Pentium in terms of performance; the balance between performance and power consumption/heat dissipation becomes more important, and this is where the PPC 970 shines. A dual PPC 970 Mac will undoubtedly be considerably faster than a single CPU Pentium system, and for the first time in years, Apple will offer the highest performance consumer desktops, by a large margin! If one 970 is about as fast as a 2.5 GHz Pentium 4, then two 970s should offer nearly twice the performance in some situations. It will be interesting to see if gamers flock to the mac...
"If you're half-evil, nothing soothes you more than to think the person you are opposed to is totally evil." N. Mailer
You are correct that the 601 was a new engineering effort and implementation of a modified Power instruction set. I did not intend to understate this fact and give the impression that it was a direct adaptation or modification of the original Power architecture (it could also be debated that the Power2 architecture is about the same distance of relation to the Power as is the PowerPC ... though not quite in the same direction ... I remember still receiving biweekly microcode updates for the Power CPU after it has been (prematurely according to some) branded Gold and released ... both the PowerPC and Power2 were much more mature).
... you are correct that it is really a case of having missed its window in the family evolution than actually being scrapped.
My "?aborted?" statement w/r to the 620 was ment to be tongue-in-cheek as IBM had given a lot of publicity (both internal and external) to the coming of the 620 since about the time it entered the design phase
Natty
Nonetheless, thank-you for your clarification.
Maybe the rain Isn't really to blame. So I'll remove the cause, But not the symptom!
Almost two decades ago, I was supporting a network modelling application that needed 12MB, and our computer was a VAX with 4MB of RAM, but fortunately 4.1BSD and System 5.2p were able to give it enough virtual memory to scrape along. Our typical runs took about a week, until a couple years later when the price of RAM dropped to the point that we could afford to upgrade to 16MB, at which time it dropped to an hour per run.
One thing we found out was that as you approach the limits of a machine's capacity, all the details of the architecture that you were able to ignore on smaller problems become visible, like how the TLBs work and what the memory page sizes are; things became somewhat clunky at 6MB and much more clunky at 22MB (or maybe 24MB), and some of that may have been the OS rather than the hardware. The extra 12MB RAM cost us approximately one person-year's salary, but unfortunately corporate accounting rules made it much harder to buy capital equipment than to make our study take a year longer.
At this point, I'm supposed to include the obligatory old-geezer rant about walking to the mainframe, five miles in the snow, uphill both ways, carrying punch-cards and hand-winding magtape, but that was back when I was an undergrad, and we didn't actually go to the mainframe, just the card-reader/printer/keypunch room which was half a mile away (still snow and hills), and the reason I handwound the magtape was because the professor's only copy had a cracked reel, though we did use hand-cranked papertape tools to do it, and I really _did_ wind papertapes by hand :-)
I haven't dealt with these problems lately - Moore's Law has long passed the limits of any problems I solve in practice, laptop diskdrive sizes have gotten two jumps ahead of Microsoft bloatware (though fitting backups onto CD-Rs feels a lot like fitting them onto floppies used to), and the only practical application I've got that could think about pushing the terabyte disk boundary is Tivo, if I'm willing to devote that much resources to something that makes me watch more television... The reason it took so long to get the 120GB drive on my 233MHz Pentium wasn't cost, it was BIOS upgrades
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
"There's nothing magical or mysterious about emulating one 32-bit architecture on another, and writing a PowerPC emulator for the x86 would not be significantly different to writing an x86 emulator for the PowerPC"
Go count up the PPC registers.. then the registers in the x86 architecture...
With JIT "acceptable" speed would be possible, but I wouldn't expect more than 601-66 performance from a high clocked P4 running interpretive PPC emulation..
BOFH excuse #207:
We are currently trying a new concept of using a live mouse. Unfortuantely, one has yet to survive being hooked up to the computer.....please bear with us.
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