Talk:PowerPC
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A big problem
This page seems to be messed up in some way. there is a curseword displayed prominently at the top of the page, and several sections appear to be missing. also, when i go in to edit the page to fix this, the text in the edit screen does not match the text displayed in the artical. dare i use the dreaded "hack" word? --Whiteknight 04:51, 15 Jun 2005 (UTC)
- Well, yahoos come along and vandalize ages all the time; apparently, they get off on it. WikiJanitors spend a lot of time mopping up these messes (by "reverting" pages back to their more-pristine state). See the Wikipedia:FAQ for more details on the reversion process (I think).
- With regard to the specific problem you had doing a reversion, it may have been caused by:
- Someone already having done the reversion in the previous moment; I did a reversion about 12 hours ago on this very page (scrub, scrub, mop, mop...).
- Some Wiki database problem or another; there are a few that cause peculiar results from time to time.
- "Finger trouble" on your part.
- In any case, it was almost certainly nothing much to worry about.
- Atlant 11:34, 15 Jun 2005 (UTC)
I took a stab at the Apple announcement
The AIM alliance ended yesterday, and I did not see an update. Therefore I made a new paragraph under "history" stating the new history. I also changed the paragraph under "design wins" to say PowerPC "has beed used" on these various platforms, not "is used" in present tense as previously written so that the design win for PowerPC with Apple can be recorded but shown to be not in use anymore.
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History section needs some work
I was recently reading this article (http://www.the400squadron.com/amug/200406/NotPowerPC.htm) by Frank Soltis talking about the history of PowerPC and the ambiguity of the name. I think the history section of this article should be changed to reflect the fact that POWER was named such retroactively, to try and differentiate it from what became known as PowerPC. If nobody else minds, I'll try to work up something. -- uberpenguin 20:35, 2005 May 24 (UTC)
I removed the sentence "One other major problem was that the 88000 (and all earlier Motorola designs) were big-endian, whereas the POWER was little-endian." because I believe it is incorrect. Evidence:
p. 234 of The PowerPC Architecture: A Specification for A New Family of RISC Processors (Second Edition, Morgan Kaufman Publishers, 1994.) indicates that the RS/6000 is a big endian architecture.
The archives of comp.arch contain many references to AIX and RS/6000 being big-endian.
I also re-wrote part of the history section, following the chronology presented in the Forward of The PowerPC Architecture (ibid.), written by Phil Hester of IBM. This appears to be a more reliable source than that of the "so the story goes" version which I replaced.
I removed claims that Apple is/was Motorola's "largest CPU customer". That is very unlikely to be true in terms of volume shipped (consider the embedded market).
Also corrected comment w.r.t. endian switch requiring a reboot. It doesn't. Added expository text on PPC endian modes in linked article. Removed reference to microcode, as it is either ambiguous or incorrect. --Kday
Some suggested changes to the PowerPC article
>>>>The 970 is a 64-bit processor derived from the POWER4 server processor. To create it, the POWER4 core was modified to be backwards-compatible with 32-bit PowerPC processors, and a vector unit (similar to the AltiVec extensions in Motorola's 74xx series) was added.
It probably should also mention the new PowerPC 970FX, which debuted in 2004. The major changes were to switch from a 130nm process to a 90nm process (which allowed the clock rate to be boosted from 1.6GHz to 2.2GHz), and to reduce power consumption from 2.5V to only 1.8V. Oh yes, and the FSB was increased as well (half the clock rate). It's also worth noting that IBM married the PPC 970/970FX chips with AMD's HyperTransport Tunnel in the BladeCenter JS20 blade servers. Interesting combination.
>>>> * 970 (PowerPC G5) (2003) 64-bit implementation derived from the IBM POWER4 enhanced with VMX (AltiVec compatible SIMD extensions), at speeds 1.4 GHz, 1.6 GHz, 1.8 GHz, 2.0 GHz and 2.5 GHz
I don't believe 1.8/2.0/2.5GHz versions of the 970 were ever shipped (although I could be wrong). I think it stops at 1.6GHz (maybe 1.8). Also, my understanding is that VMX isn't merely "AltiVec-compatible". VMX, AltiVec and Velocity Engine are the same thing, just marketed under different names by the three companies.
You might add another line for the 970FX, such as:
>>>> * 970FX (PowerPC G5) (2004) 90nm version of the 970, at speeds 1.8 GHz, 2.0 GHz, 2.2 GHz*, 2.5 GHz
Note the addition of a 2.2 GHz speed. This is the chip used in the current IBM JS20 blade.
Take care.
Mark (mchapman@us.ibm.com)
Can somebody include some info about the PowerPC embedded cores present in Xilinx VirtexII-Pro and Virtex 4 LX FPGAs? Jimgeorge
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Doesn't current fastest computer in the world, Blue Gene, use PowerPC400 32-bit cpus? It says in this article that PPC440 is used for embedded systems and not mainframe high performance supercomputers ?? Is this a shift for PPC440 from embeded systems to supercomputers? Why use such "weak" processor in world's fastest computer and what's so special about it? Other processors would be a much better choice (faster clock, 64-bit, etc.)..
- Yes, Blue Gene/L uses IBM PowerPC 440 chips. The reason IBM did not opt for something as beefy as POWER5 or perhaps PowerPC 970 is because using these chips wouldn't buy very much in the way of cluster computing performance. CPUs designed for massive I/O performance with a hefty load of cache aren't necessarily desirable for a cluster computer. It makes a lot more sense to use cheaper, abundant, easy to manufacture, and slightly more "stripped-down" processors in compute nodes due to the nature of the kind of tasks generally assigned to a distributed computer. Faster clocks cause more power to be dissipated, 64-bit datapaths increase transistor count within the same (or similar) design, but it buys nothing in the way of performance (unless you are dealing with data sets of VERY large integers or HUGE data chunks, both being somewhat rare since a lot of supercomputing-worthy tasks are floating-point intensive and easily broken into many smallish pieces). What is special about the PowerPC 440 is that it is a fairly small and simple PowerPC implementation that can be run at a fairly high clock speed but doesn't dissipate the massive amounts of power that larger, more complex chips do. In other words, it's a good choice simply BECAUSE it isn't, in itself, all that spectacular. -- uberpenguin 01:01, 2005 May 12 (UTC)
PowerPC 615
Back in 1995/1996 there was a rumored PowerPC 612/615 with builtin x86 intruction support (see [1] (http://www.theregister.co.uk/1998/10/01/microsoft_killed_the_powerpc/) for example). Anyone have more info on this? It might make a reasonable addition to this article, since there was a lot of buzz about it in the early PowerPC days. -- Kaszeta 14:24, 6 Jun 2005 (UTC)
- While I don't have the info off the top of my head, I belive I have read a book from my college library stating of a PowerPC 612. I'll go ahead and re check the book, and fully answer the question once i'm in the library [wireless nodes are great, arn't they?] CoolFox 14:39, Jun 6, 2005 (UTC)
- OK! I'm in the campus library, and I found the book. Its called The PowerPC Revolution, page 175. [ISBN: 1-883577-04-7]. It states that in Autumn of 1993, IBM CPU engineers were working on a PPC chip that provides x86 instruction-set support as a subsystem directly on the CPU. The chip is being developed as a solely IBM product, outside of the PowerPC alliance [AIM]. In short, the 615 is a chip that runs native PPC code, and native x86 code, being able to run Windows and DOS without any emmulation. I hope this is all helpful. --CoolFox 17:36, Jun 6, 2005 (UTC)
- Thanks, I'll add mention of this to the page. -- Kaszeta 18:22, 6 Jun 2005 (UTC)