| Re: NaN Magic or Why Me?! [message #56750] |
Tue, 13 November 2007 12:30  |
Mort Canty
Messages: 134
Registered: March 2003
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Senior Member |
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R.G. Stockwell schrieb:
>
> Can you reproduce the problem with a small subset of the code
> (hopefully with some randomly generated data) and post it
> here?
>
>
> Cheers,
> bob
>
>
Hi Bob,
I hope so, but it's a fairly big program. It's getting late here in
Germany, so I'll try to distill things out tomorrow. Thanks for the
interest.
Mort
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| Re: NaN Magic or Why Me?! [message #56752 is a reply to message #56751] |
Tue, 13 November 2007 11:36  |
Mort Canty
Messages: 134
Registered: March 2003
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Senior Member |
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Rick Towler schrieb:
>
>
> Mort Canty wrote:
>
>> I'd like to post the code so you, too, can amaze your friends,
>> but unfortunately the trick only works on my bloody computer.
>>
>> Seriously, can someone, anyone, tell me might be going on?
>
> How many other computers have you tried this on? Make/Model/Processor?
>
> Just a guess, but MS released "A microcode reliability update that
> improves the reliability of systems that use Intel processors". They're
> talking the Core 2 architecture (Core 2 variants and Xeon 3x and 5x). I
> believe that this was delivered as a critical update via the automagic
> update system so you may already have it installed but it would be worth
> checking.
>
> More info is here: http://support.microsoft.com/kb/936357
>
> -Rick
The errors occur on an ACER Veriton 7800 with intel P4 650, and
Lakeport-G i945G chipset running XP Professional SP2. So I guess it has
nothing to do with the MS update. I get no errors on my ASUS core-duo
laptop with the same OS (it's not here just now, so I don't know the
details). Ditto on an older P4 no-name with same software. I'll try a
few more, though, thanks.
Mort
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| Re: NaN Magic or Why Me?! [message #56826 is a reply to message #56752] |
Wed, 14 November 2007 09:45 |
Rick Towler
Messages: 821
Registered: August 1998
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Senior Member |
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Mort Canty wrote:
> Rick Towler schrieb:
>>
>>
>> Mort Canty wrote:
>>
>>> I'd like to post the code so you, too, can amaze your friends,
>>> but unfortunately the trick only works on my bloody computer.
>>>
>>> Seriously, can someone, anyone, tell me might be going on?
>>
>> How many other computers have you tried this on? Make/Model/Processor?
>>
>> Just a guess, but MS released "A microcode reliability update that
>> improves the reliability of systems that use Intel processors".
>> They're talking the Core 2 architecture (Core 2 variants and Xeon 3x
>> and 5x). I believe that this was delivered as a critical update via
>> the automagic update system so you may already have it installed but
>> it would be worth checking.
>>
>> More info is here: http://support.microsoft.com/kb/936357
>>
>> -Rick
>
> The errors occur on an ACER Veriton 7800 with intel P4 650, and
> Lakeport-G i945G chipset running XP Professional SP2. So I guess it has
> nothing to do with the MS update. I get no errors on my ASUS core-duo
> laptop with the same OS (it's not here just now, so I don't know the
> details). Ditto on an older P4 no-name with same software. I'll try a
> few more, though, thanks.
Since you code runs fine on 2 out of 3 computers the problem most likely
is hardware based. Since you've swapped your SO-DIMM, and this is a
laptop, you don't have many options left.
RAM->BIOS->Heat->Power
Even late in a processor's life cycle, there are a number of "errata"
that exist. Generally workarounds are implemented either in the BIOS or
in the OS. I would get the latest BIOS available for your laptop.
Also, try disabling hyperthreading in the BIOS. You never know...
If your processor has active cooling ensure that the fan and heatsink
are clean and that the fan spins freely. If this is an actual P4 650
"Prescott", aka Pres-Hot, heat is a real issue. Stick it in the
refrigerator while you test it.
Power issues are tricky to diagnose in laptops but if the above steps
don't help, and you tend to get errors while the system is loaded, there
could be components in your AC/DC adapter or the regulators on the
mainboard that are marginal. All you really can do is look for obvious
defects like bulging or leaking capacitors or swap the adapter if you can.
HTH,
-r
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| Re: NaN Magic or Why Me?! [message #56830 is a reply to message #56751] |
Wed, 14 November 2007 06:48 |
Mort Canty
Messages: 134
Registered: March 2003
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Senior Member |
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R.G. Stockwell schrieb:
> "Mort Canty" <m.canty@fz-juelich.de> wrote in message
> news:fhcua7$b06o$1@zam602.zam.kfa-juelich.de...
>
>> The errors occur on an ACER Veriton 7800 with intel P4 650, and Lakeport-G
>> i945G chipset running XP Professional SP2. So I guess it has nothing to do
>> with the MS update. I get no errors on my ASUS core-duo laptop with the
>> same OS (it's not here just now, so I don't know the details). Ditto on an
>> older P4 no-name with same software. I'll try a few more, though, thanks.
>
>
> Can you reproduce the problem with a small subset of the code
> (hopefully with some randomly generated data) and post it
> here?
>
>
> Cheers,
> bob
>
Having reduced the code, as you suggested, to what I assumed to be "the
essentials", the problem disappeared. So now I'll have to put back "the
inessentials" one-by-one until the NaNs re-appear. Tedious, but maybe
also a good way of tracking it down. I'll get back here later (I hope).
Cheers,
Mort
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