what is a kernal panic?

public enemy

macrumors regular
Original poster
Jun 7, 2005
107
0
COLORADO
i have read numerous posts with problems of screens going black/dim/lines etc. and people refering to a kernal panic, what is this? how do you prevent them?
 

public enemy

macrumors regular
Original poster
Jun 7, 2005
107
0
COLORADO
that does nothing for me, you type in kernal panic, and its everyones problems, not what it is. im asking what it is? what is the definition?
 

Plymouthbreezer

macrumors 601
Feb 27, 2005
4,239
76
Massachusetts
Well first off, you're spelling it wrong. It's "Kernel" not "Kernal."

Since you obviously can't go to google and type "Define:Kernel Panic" I'll post a definition.

A kernel panic is a message displayed by an operating system upon detecting an internal system error from which it cannot recover. Kernel panics often provide cryptic debugging information that is useful only to the developers of the operating system.
 

Eniregnat

macrumors 68000
Jan 22, 2003
1,841
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In your head.
You will know that you have had a kernel pannic when you see this screen (pardon the deep link).



In short the Kernel is the fundamental link between software and the hardware. If something glitches at either end, the kernel panics. Think of it as the base of the OS, but not the BIOS (built in opperating system- used for boot).

Go here for info. The site linked will also connect you to information about the spinning beachball of doom (not a kernel pannic).


Control-Close Apple- Reset -> Kernel OK.
That's old school.
 

Lucky8

macrumors regular
May 18, 2005
218
0
When it just shuts off all by itself, does that mean Kernel Panic also? :confused:
My Dual 1.8 G5 did that this morning with only iTunes, Mail and Safari running. I booted up right away and it was fine ever since. :(
I suspected it was maybe too hot but the fan didnt even come on. Unless they were so quiet I didnt hear them.
CPU A = 148, CPU B = 138 degrees F but I had seen as high as 158 - 168 degrees F when superdrive is burning DVD.
Anyway, is 6 inches from the back of the computer to the wall good enough or does it need more room than that?
 

iMeowbot

macrumors G3
Aug 30, 2003
8,643
0
Lucky8 said:
When it just shuts off all by itself, does that mean Kernel Panic also? :confused:
Maybe, maybe not. You can use the Console program in Applications:Utilities to see if the system recorded anything interesting at the time.

Is 138 - 148 degrees F too hot?
Yes, way too hot (if you mean that was the room temperature -- which after your edit, it seems you didn't.).

What happens is if the room temperature is too high, the cooling system is running a losing battle to keep the CPU temperature low. Look for messages about runaway or similar in console.
 

buryyourbrideau

macrumors 65816
Mar 1, 2005
1,212
0
Chicago
iMeowbot said:
Maybe, maybe not. You can use the Console program in Applications:Utilities to see if the system recorded anything interesting at the time.


Yes, way too hot (if you mean that was the room temperature -- which after your edit, it seems you didn't.).

What happens is if the room temperature is too high, the cooling system is running a losing battle to keep the CPU temperature low. Look for messages about runaway or simliar in console.
nah. it was cpu a and b temp as posted. which isnt high at all especially for a PM i think. my ibook at its hottest has been about that temp.

EDIT: just got beat, and i was the beater earlier haha
 

Lucky8

macrumors regular
May 18, 2005
218
0
iMeowbot said:
Maybe, maybe not. You can use the Console program in Applications:Utilities to see if the system recorded anything interesting at the time.
Does this mean anything to you = "Jun 15 16:15:10 localhost kernel[0]: ApplePMU::pMU FORCED SHUTDOWN, CAUSE = -122"

Yes, way too hot (if you mean that was the room temperature).
No, thats the CPU temp.
 

iMeowbot

macrumors G3
Aug 30, 2003
8,643
0
Lucky8 said:
Does this mean anything to you = "Jun 15 16:15:10 localhost kernel[0]: ApplePMU::pMU FORCED SHUTDOWN, CAUSE = -122"
PMU is Power Management Unit. -122 is a common one, it could be as simple as a quick power drop. Don't worry unless it comes back.
 

Lucky8

macrumors regular
May 18, 2005
218
0
iMeowbot said:
PMU is Power Management Unit. -122 is a common one, it could be as simple as a quick power drop. Don't worry unless it comes back.
But I have my G5 hooked up to a UPS.
Do you think the voltage can still drop with UPS?
 

thecow

macrumors 6502
Nov 24, 2003
400
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Timonium MD
If you have a G5 and a monitor and a few other things plugged into the UPS, it might not be able to handle it if the power goes out for too long. Save all of your work on the PM and unplug the UPS from the wall to see if the UPS can handle everything.
 

iMeowbot

macrumors G3
Aug 30, 2003
8,643
0
Lucky8 said:
But I have my G5 hooked up to a UPS.
Do you think the voltage can still drop with UPS?
They aren't perfect. Then again, Mac PMUs aren't perfect either. You can try resetting the PMU (or SMU, depending on your G5's vintage -- info should be in the manual), but pay heed to the part about not pressing the button twice: they mean it.
 

Eniregnat

macrumors 68000
Jan 22, 2003
1,841
0
In your head.
Lucky8 said:
But I have my G5 hooked up to a UPS.
Do you think the voltage can still drop with UPS?
Yes. I admin a recording studio. We have dozens of really expensive (and very good UPSs) Our primary and secondary network servers draw a lot of power, and the UPSs for them don't do as well with the ultra short voltage drops. We are installing a couple of power conditiners, wich in this case will run us 3K. I used to think that a UPS was a power conditioner was the same, and they are not.

Your UPS may actualy have trapped the data necessary to determin what happend. If it as a USB port and it came with software, you might have an answer.

You can also call the power company if you have evidence that the drops are because of issues not dealing with the AC in your house of bussness, but you need data to prove that.