[Linux-ia64] Re: Itanium gets supercomputing software

[Linux-ia64] Re: Itanium gets supercomputing software

[David Kågedal]

Matt Chapman <matthewc@cse.unsw.edu.au> writes:

> On Fri, Apr 11, 2003 at 09:58:08AM +1000, Duraid Madina wrote:
>> 
>> I put it to you that software is easier to develop on hardware. Nothing 
>> unique to IA64, indeed.
>
> We still use simulators despite the availability of hardware.  Operating
> system software is often easier to debug on a simulator.

Exactly.  There are a lot of things that you can do with a simulator
that you can't do with hardware.  Developing software before hardware
is available is just one of them.  (plug mode on) That's why we sell
simulators for most major current CPU architectures.  Including IA64.

-- 
David Kågedal, Virtutech
http://www.simics.com/

Re: [Linux-ia64] Re: Itanium gets supercomputing software

[Duraid Madina]

I guess I was being a bit subtle.

I'm well aware there are things you can do with a simulator that you 
can't do with hardware. Like test your code against what's supposed to 
happen, not what actually happens. ;)

My point wasn't that software simulators are useless, but that software 
simulators _should_ be useless **4 years** (!!) after the public 
availability of hardware.

When I said:
 > I put it to you that software is easier to develop on hardware.

I meant that at this late stage, one would expect that people would be 
writing software, on their hardware. And not a whole lot else, all 
things considered. Do you see x86 linux people using simulators? Once in 
a blue moon, perhaps. Does anyone doubt that the x86-64 port will mature 
a heck of a lot faster than linux-ia64 has? One doesn't need to think 
for very long to realise why this might be.

Don't get me wrong, I think Linus was being a complete idiot for his 
comments against IA64 and for x86-64, but insofar as keeping hardware 
pricing so high that Joe K. Hacker can't even dream of affording it is 
"good business" on Intel/HP's part, it's an even better way of keeping 
your kernel untested.

	Duraid

David Kågedal wrote:
> Exactly.  There are a lot of things that you can do with a simulator
> that you can't do with hardware.  Developing software before hardware
> is available is just one of them.  (plug mode on) That's why we sell
> simulators for most major current CPU architectures.  Including IA64.

Re: [Linux-ia64] Re: Itanium gets supercomputing software

[David Mosberger]

>>>>> On Sat, 12 Apr 2003 06:49:35 +1000, Duraid Madina <duraid@octopus.com.au> said:

  Duraid> My point wasn't that software simulators are useless, but
  Duraid> that software simulators _should_ be useless **4 years**
  Duraid> (!!) after the public availability of hardware.

Then how do you explain the popularity of user-mode linux on x86?

The reason I continue to use Ski is because it's one of the very few
simulators out there that are (a) architecturally extremely accurate,
(b) fast, and (c) very easy to setup & use.  Ski is an asset for ia64
linux, not a weakness.

(And no, just because we have Ski doesn't mean we don't use real
 hardware.  Nothing could be further from the truth.)

	--david

Re: [Linux-ia64] Re: Itanium gets supercomputing software

[Duraid Madina]

David Mosberger wrote:
>>>>>>On Sat, 12 Apr 2003 06:49:35 +1000, Duraid Madina <duraid@octopus.com.au> said:
> 
>   Duraid> My point wasn't that software simulators are useless, but
>   Duraid> that software simulators _should_ be useless **4 years**
>   Duraid> (!!) after the public availability of hardware.
> 
> Then how do you explain the popularity of user-mode linux on x86?

If user-mode linux is "popular", then linux is "f@#%g buggy s#!t". I 
mean really, when your attitude to software development is:

	<Linus> hey somethings wrong my swap is full what gives????
	<Rik Riel> stop running 91589 copies of XMMS 8)
	<Linus> shut up riel god i hate you
	** Riel is banned from linux-kernel
	<Andrea> YO CHECK OUT THE NEW VM SYSTEM I WROTE THIS 
MORNING^H^H^H^H^H^H^HWEEK!! ITLL FIX YOUR PROBLEMS!!!!
	<Linus> k i know 2.4 is supposed to be a "stable" kernel but god i hate 
that riel dude!! :| welp.. out with the old, in with the new!!!!!
	** Linus integrates new VM
	<Andrea> THANKS D00D
	<Linus> no probs m8

	..then yes, having UML as a sandbox can help.

The UML guys see it differently though. According to them: "It doesn't 
need to be good for anything. It's fun!" Maybe Ski can embrace this 
spirit also. ;)

  > The reason I continue to use Ski is because it's one of the very few
> simulators out there that are (a) architecturally extremely accurate,
> (b) fast, and (c) very easy to setup & use.  Ski is an asset for ia64
> linux, not a weakness.
> 
> (And no, just because we have Ski doesn't mean we don't use real
>  hardware.  Nothing could be further from the truth.)

That's right - _you_ use real hardware because you actually have it. 
Everyone else (figuratively speaking, though it's not far off the mark) 
has no choice _but_ to use Ski. That sucks, regardless of whether or not 
Ski is accurate, fast, or easy to use.

Anyway, I don't think there's much more that can be said. As Matt 
indicated, we must pray for Deerfield, so I will continue to align my 
holy carpet of hope to Fort Collins/Portland/Carly's hotel bedroom and 
pray for reasonably priced IA64 hardware.

	Duraid

Re: [Linux-ia64] Re: Itanium gets supercomputing software

[David Mosberger]

>>>>> On Sat, 12 Apr 2003 08:54:56 +1000, Duraid Madina <duraid@octopus.com.au> said:

  Duraid> That's right - _you_ use real hardware because you actually have it. 
  Duraid> Everyone else (figuratively speaking, though it's not far off the mark) 
  Duraid> has no choice _but_ to use Ski. That sucks, regardless of whether or not 
  Duraid> Ski is accurate, fast, or easy to use.

  Duraid> Anyway, I don't think there's much more that can be said. As Matt 
  Duraid> indicated, we must pray for Deerfield, so I will continue to align my 
  Duraid> holy carpet of hope to Fort Collins/Portland/Carly's hotel bedroom and 
  Duraid> pray for reasonably priced IA64 hardware.

Anyone can get access to ia64 hardware at:

	http://testdrive.hp.com/

They're shared machines, so kernel development is out, but for
user-level development, they are very handy.

	--david

[Linux-ia64] Re: Itanium gets supercomputing software

[David Kågedal]

Duraid Madina <duraid@octopus.com.au> writes:

> I guess I was being a bit subtle.
>
> I'm well aware there are things you can do with a simulator that you
> can't do with hardware. Like test your code against what's supposed to
> happen, not what actually happens. ;)
>
> My point wasn't that software simulators are useless, but that
> software simulators _should_ be useless **4 years** (!!) after the
> public availability of hardware.

Why is that?  There are numerous reasons for using simulators to
develop software, especially low-level software (OS, drivers, firmware
etc.)  You get things like full system visibility, non-intrusive
debugging, deterministic repeatability, fault injection, and more.

-- 
David Kågedal, Virtutech