UX, AIX, FLAYX...

[Patrick Finnegan]

On Tuesday 04 September 2007, Liam Proven wrote:
> On 04/09/07, Patrick Finnegan <pat at computer-refuge.org> wrote:
> > On Monday 03 September 2007 17:41, Liam Proven wrote:
> > > On 03/09/07, William Donzelli <wdonzelli at gmail.com> wrote:
> > > > > I have a number of PowerMacs for that side of things. :¬)
> > > >
> > > > The PowerPCs in Macs are the retarded little brothers of the
> > > > real POWER processors.
> > >
> > > Arguably, this may be so, but I'd submit two rather important
> > > riders on to that.
> > >
> > > [1] Whereas this was the case with the 601/603/604 and so on, I'm
> > > not sure it's really true any more. The "G5" is pretty much a
> > > 2-core POWER4, AIUI
> >
> > As I've read, the 601 is more POWER than the rest of the PPC chips.
> > Still much slower and dumbed down than the proper POWER (non-PC)
> > versions.
>
> Can you give some supporting evidence for that assertion? I've been
> following the development of POWER and PowerPC since their first
> announcements, and as far as I can see, the process has been one of
> gradual convergence. The PPC601 was a single-chip implementation of
> what was still a processor /chipset/ on the IBM side - IIRC, I think
> the contemporary IBM processor was spread over 5 chips or something.

I don't feel like looking this up.  Go look at SPECfp numbers for PPC 
and POWER chips of the same era, for a starting point.  There's also a 
number of POWER architecture descriptions floating around the internet 
which detail differences.

> > And you have that backwards, the G5 is 1/2 of a POWER4 chip.
>
> I have nothing whatsover backwards and kindly don't make assumptions.
> I stated that the "G5" - the PPC970 family - is a dual-core POWER4;
> given that I was talking to someone who claims good knowledge of the
> POWER processors but seems not to be so /au fait/ with PowerPC, I did
> not see any necessity to spell out that POWER4 is a quad-core design.
> PPC970 also adds Altivec-compatible SIMD instructions to POWER, but
> is a highly capable 64-bit implementation of POWER.

The POWER4 is dual core, the original G5 is single core.  The newest G5 
is dual core.  IBM didn't make ANY quad-core processors until the 
POWER5+.

> I'm not aware of much that modern PPC processers can't do that POWER
> can, other than things intended for the support of legacy IBM OSs
> such as OS/400 or zOS.

The POWER chips have a bunch of hypervisor goo, and many, many MBs of L3 
cache on the multicore versions.

> > I guess a
> > dual-core G5 is close to a POWER4, but it's still lacking some
> > things, like cache.
>
> (?) The 970 has onboard primary and secondary cache. In the first
> model, 64KB of direct-mapped L1 instruction cache and 32KB of L1 data
> cache, plus 512KB of 2-way associative L2 cache.

I wasn't say it was without *any* cache.  It just has a lot less than 
POWER4.  No one builds modern processors without ANY cache, that'd just 
be silly.

> >  And, the G5 has VMX/Altivec, which the POWER4 doesn't.
> > Mostly, the POWER4 was designed to be a enterprise server grade
> > CPU, and the G5 is designed to be a consumer-grade CPU.  There's a
> > lot of trade-offs that they made when designing one vs the other.
>
> They discuss the tradeoffs between POWER4 and PPC970 in some detail.
> The PPC is and always has been a desktop processor for the retail
> consumer market; its rivals were the Athlon64 and Pentium 4D. As such
> it's tuned towards different demands than the POWER4, which is aimed
> for expensive, non-cost-sensitive IBM servers, minis and mainframes -
> not that there's a lot of difference between those 3 categories
> today.
>
> To copy the 1st article I link's summary of the differences: "In sum,
> the 970 is made to be faster, cheaper, and significantly less
> reliable than the Power4."

Why should I read those?  That was the exact point I was trying to make.

> > The POWER5 and POWER6 are quite a bit more interesting than any
> > PowerPC chip.
>
> Yes, arguably, but now Apple has abandoned the PPC, it's dead in the
> water as far as the desktop is concerned, so it won't really evolve
> any further. (Which I think is a great shame.)

POWER5 and POWER6 have evolved quite a bit from where POWER4 was.  IBM 
made a lot more money selling POWER processors, systems, and consulting 
to go with it, than they ever did with selling PPC chips to apple.  IBM 
was dragging their feet with PPC features on the G5 (and whatever would 
have been G6), which is why Apple abandoned them; if IBM was making 
enough money from Apple on their G5s,  I'm sure that they would have 
payed more attention to what Apple wanted (like low-power noteboot 
CPUs).

> On the other hand, in the embedded market, there are fascinating
> chips like PA Semi's PWRficient line.
>
> http://news.zdnet.com/2100-9584_22-5907281.html
> http://www.theregister.co.uk/2005/10/24/pasemi_power/print.html
>
> These will carry the torch forward for PPC, but we won't find them in
> any affordable desktop machines.

Depends on what you mean by "affordable".  Easily more affordable than 
an inflation-adjusted IBM 5150 or similar.

> > > [2] All the interesting apps and the desktop-relevant stuff is on
> > > PowerPC. Specifically, on OS X. Even a 10y old G3 Mac with OSX
> > > makes a pleasant and usable machine for the Web today and for
> > > day-to-day use. I can't think of a lot of use for a 10yo RS/6000
> > > except as a server - as a workstation running Motif or something,
> > > it wouldn't be much use on the desktop today.
> >
> > Interesting depends on what you mean by it.
>
> Well, of course, but I went on to define what I meant in the same
> sentence on the same line. Desktop-relevant stuff that I can actually
> use. I'm reading and writing this on a web page; for the 2007 Web, I
> need a modern CSS2-capable browser, Flash, Javascript, Java,
> RealPlayer, QuickTime and Windows Media support. OS X delivers those;
> even PowerPC Linux, probably the most-widely-supported desktop Unix
> environment on PPC, does not.

Whether or not you need Flash is a matter of debate... but a lot of that 
can be handled by firefox, IBM's PPC JREs, and mplayer/xine.  Who needs 
three separate media players, when you can use one of two OSS players, 
and play almost anything.  I hear that the OSS flash player is even 
very close to being able to play youtube/google flash videos.  But, 
alas, this still doesn't make a platform intersting to me.

> > POWER has AIX and i5/OS / OS/400.  by themselves, much more
> > interesting to me than anything that runs on MacOSX.  Of course,
> > I'm "one of those people" who runs Linux on their work-provided
> > PowerMac G5.  I just can't seem to get my boss to want to pay $10k
> > for a proper POWER5 workstation from IBM. ;)
>
> A snag!
>
> I find these to be academically interesting OSs, ones I'd like to
> work with and know more about, but neither I nor my small-business
> clients have any direct personal or professional use or need for
> them. Unlike a Mac.

Who said personal/professional use?  I though that people collected 
computers because they were "interesting", not just because they were 
useful.

Pat
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