SGI files chapter 11

Ian Mapleson · *nix forums addict Joined: 29 Apr 2005 Posts: 54

Ian Mapleson · *nix forums addict Joined: 29 Apr 2005 Posts: 54

Tony 'Nicoya' Mantler wrote:

Eric Belhomme · *nix forums beginner Joined: 18 Jul 2005 Posts: 31

AlbaClause <you@cogeco.ca> wrote in
news:DVIag.74310$fd.30883@read2.cgocable.net:

I understand what you mean, and I think you're right, but I still think
"old school commercial/prorietary unices" like SCO/UNIX, AIX, or IRIX are
in end of life, mainly for 2 reasons :
- it costs huge money to editors to maintain and enhance them,
- mentalities evolved in profit of open-source for many reasons (community
support, quality of the code*, transparency..

In fact, Sun understood that, so they moved Solaris to OpenSolaris. this
will probably ensure continuation of Solaris for incoming years...

[*] yes I know : open-source is not a synonym of proper code Wink

--
Rico

You · *nix forums beginner Joined: 02 Jul 2005 Posts: 38

Eric Belhomme wrote:

Eric Belhomme · *nix forums beginner Joined: 18 Jul 2005 Posts: 31

AlbaClause <you@cogeco.ca> wrote in
news:GCkag.73685$fd.21312@read2.cgocable.net:

Tony 'Nicoya' Mantler · *nix forums Guru Wannabe Joined: 02 Jul 2005 Posts: 139

In article <wMvag.37552$Hk1.23865@read1.cgocable.net>,
AlbaClause <you@cogeco.ca> wrote:

: Hmmm, there are no supercomputers that run OS X?

Number 15, Mach 5 at COLSA, runs OS X, as does Number 20, System X at Virginia
Tech (which made the headlines a few years ago). There's a total of 4 in the
current Top-500 list (#303 "Dawson" at UCLA, #308 "Xseed" at Bowie State
University).

Cheers - Tony 'Nicoya' Mantler :)

--
Tony 'Nicoya' Mantler - Master of Code-fu
-- nicoya@ubb.ca -- http://www.ubb.ca/ --

<rambam@bigpond.net.au · *nix forums beginner Joined: 05 Mar 2006 Posts: 7

AlbaClause <you@cogeco.ca> writes:

You · *nix forums beginner Joined: 02 Jul 2005 Posts: 38

Walter Roberson wrote:

You · *nix forums beginner Joined: 02 Jul 2005 Posts: 38

rambam@bigpond.net.au wrote:

Tony 'Nicoya' Mantler · *nix forums Guru Wannabe Joined: 02 Jul 2005 Posts: 139

In article <1quag.168976$P01.161809@pd7tw3no>,
roberson@hushmail.com (Walter Roberson) wrote:

: In article <nicoya-10E968.17084216052006@shawnews.wp.shawcable.net>,
: Tony 'Nicoya' Mantler <nicoya@ubb.ca> wrote:
: >The
: >growing gap between core speeds and RAM speeds makes having a compact ISA more
: >important than having a simple one, so in fact one could say that CISC has "won
: >the war" on technical merit.
:
: I wouldn't say that compact is more important than simple: if you
: have an ISA with -predictable- instruction length, you can go
: parallel on the instruction load.

Well, there's two steps you need to undertake to decode a CISC instruction.
First you need to determine the length of the instruction, then you need to
split it into RISC sub-instructions.

Only the first step is affected by a lumpier instruction set, and it's a very
small step that doesn't have to be performance limiting.

: If compact was important then a bit-sliced compressed ISA would
: have the advantage; if predictable is important, then VLIW has the
: advantage.

The failure of VLIW is actually kind of unfortunate. It's a fairly good chip
design to use if you want to emulate other ISAs or bytecodes, but for some
reason people have a strange attraction to trying to static-compile code
directly for VLIW ISAs, which leads to miserable failure.

There isn't enough data available at compile time to optimize to the level
required to make VLIW dance, but there is enough data at run time to hot-spot
optimize during execution.

I wouldn't be surprised if you could emulate IA64 faster than you could run it
native on the same chip.

: One could imagine an architecture in which N bits at a time are
: loaded in parallel, with each instruction being either N or N/2 bits
: long, and the N-bit instructions always being N-bit aligned.
: (i.e,, each N-bit boundary has either one N-bit instruction or
: two N/2-bit instructions, or one N/2-bit instruction and a N/2-bit NOP.)
:
: The alternative is to pull complete fixed-length cache-lines worth
: of instructions out, and have an internal buffer that advances as
: much as is needed according to the CISC instruction length; I suspect
: this would tend to have cache stalls waiting for the rest of the
: instruction to load, unless the cache-line size is big enough that
: the CPU can't process a cache-line's worth of instructions before
: the next cache line is ready...
:
: Probably someone's already simulated all of these possibilities ;-)

Most of the lumpiness in the x86 instruction set has been ironed out over the
years, so that it's trivial to determine the length of the common subset of
instructions. The uglier instructions still exist, but only outside the critical
path so handling them isn't a performance concern.

Making cache loads more predictable by filling half of it with nulls isn't a net
gain. :)

Cheers - Tony 'Nicoya' Mantler :)

--
Tony 'Nicoya' Mantler - Master of Code-fu
-- nicoya@ubb.ca -- http://www.ubb.ca/ --

<rambam@bigpond.net.au · *nix forums beginner Joined: 05 Mar 2006 Posts: 7

Tony 'Nicoya' Mantler <nicoya@ubb.ca> writes:

Walter Roberson · *nix forums Guru Joined: 19 Feb 2005 Posts: 1300

In article <nicoya-10E968.17084216052006@shawnews.wp.shawcable.net>,
Tony 'Nicoya' Mantler <nicoya@ubb.ca> wrote:

Tony 'Nicoya' Mantler · *nix forums Guru Wannabe Joined: 02 Jul 2005 Posts: 139

In article <Xns97C5847665DBBericbelhommefreefr@212.27.42.136>,
Eric Belhomme <{rico}+no/spam@ricospirit.net> wrote:

: Intel/AMD competition does not produce new technologies, it just enhance
: x86 architecture (engraving, frequence, pipeling,...)

I'd have to disagree with you. The x86 chips have been running RISC-style cores
since around the PPro, and the instruction translation engines have been refined
to the point where they're almost free from a performance standpoint. The
growing gap between core speeds and RAM speeds makes having a compact ISA more
important than having a simple one, so in fact one could say that CISC has "won
the war" on technical merit.

Add to that the transition to AMD64, which cleans up a lot of the ugly corners
of the ISA and you have a great base to build a world class CPU on.

AMD brought NUMA to the $500 desktop, Intel fixed up the ISA to allow full
virtualization, both have worked on adding and refining SIMD extensions. All the
technologies that used to be the domain of million dollar supercomputers are now
available for everyone.

Maybe we won't see a completely ground-up redesign on the ISA any time soon, but
do we really need one? The ugly duckling is all grown up now.

Cheers - Tony 'Nicoya' Mantler :)

--
Tony 'Nicoya' Mantler - Master of Code-fu
-- nicoya@ubb.ca -- http://www.ubb.ca/ --

Tony 'Nicoya' Mantler · *nix forums Guru Wannabe Joined: 02 Jul 2005 Posts: 139

In article <Xns97C5821AF2536ericbelhommefreefr@212.27.42.136>,
Eric Belhomme <{rico}+no/spam@ricospirit.net> wrote:

: Tony 'Nicoya' Mantler <nicoya@ubb.ca> wrote in
: news:nicoya-0DB257.22262509052006@shawnews.wp.shawcable.net:
:
: > It's not the end of SGI, it's the end of big UNIX. SGI should be proud
: > to have been one of the last holdouts in a dying market.
: >
: No big Unices still alive :
: - GNU/Linux
: - OpenBSD
: - FreeBSD
: - NetBSD
:
: These Unices are massivelly supported on almost all computer architectures
: that has been or will be !
:
: I think the market for _commercial_ unix is ended... Do you fell the
: difference ?

I think you misunderstood my post. The "big UNIX" was referring to was the old
classic UNIX systems like IRIX, AIX, HP-UX, Tru-64, Solaris, etc.

The open-source UNIX-like systems are a much different market, though they are
primarily eroding the market that the old UNIX systems once dominated in.

MacOS X is about as far from UNIX as you can get and still be able to compile
and run UNIX code. The core of MacOS X isn't UNIX. The APIs, the windowing, the
workspace, the file hierarchy, pretty much everything that makes an OS an OS is
done the MacOS X way, not the UNIX way. Most relevant to my argument, Mac
systems mostly don't occupy the same market space as old UNIX systems did,
though they have made inroads in places.

Cheers - Tony 'Nicoya' Mantler :)

--
Tony 'Nicoya' Mantler - Master of Code-fu
-- nicoya@ubb.ca -- http://www.ubb.ca/ --

You · *nix forums beginner Joined: 02 Jul 2005 Posts: 38

telleson@sbcglobal.net wrote:

Google