What is a kernel panic?

Discussion in 'Mac Basics and Help' started by Bigtree, Sep 13, 2007.

  1. Bigtree macrumors 6502

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    #1
    Sorry for such a basic question. :confused:

    I hope it's not a piece of corn getting wedged between the space bar and the command key!:D
     
  2. Coprolite macrumors member

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    #2
    http://guides.macrumors.com/Kernel_panic

    Courtesy of the Guides tab:

    A kernel panic is the most fatal crash that can occur under Mac OS X. They are often referred to as "KPs", "panics" or compared to a BSOD - Blue Screen of Death on Windows operating systems. To recover from a kernel panic you will need to reboot your machine by holding down the power button for several seconds, wait until the computer has completely shut down and then press the button again to start up as normal. Kernel panics are extremely rare. A healthy system should experience no more than one kernel panic per year at the most.

    :)
     
  3. Bigtree thread starter macrumors 6502

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    #3
    Thanks for the quick reply!!

    So the other day, I came home to find my computer with a blue screen, and was froze. Was this kernel panic?
     
  4. Coprolite macrumors member

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    #4
    If you go to your Applications\Utilities folder you will find console.app

    This is an easy way to read all the log files that you have. Once you launch it, there is a button marked "Logs" in the top left hand corner of the window. This will bring up a list of all the different kinds of logs that you can browse.

    I believe that panic.log is the one that you'd like to check. It lists your kernel panics. I had two kernel panics since November 2005 (Sept 06 and March 07).

    :)
     
  5. Sherman Homan macrumors 6502

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    #5
    Usually with a kernel panic you will see a scary multi-language screen telling you to restart. Most common reason with late model Macs is bad ram, although silly little software problems can cause a panic also. A locked up Mac with a plain blue screen is most likely a system freeze attempting to wake up from sleep mode. That could be a whacked out PRAM or PMU.
     
  6. TBi macrumors 68030

    TBi

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    #6
  7. Sesshi macrumors G3

    Sesshi

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    #7
    Imagine lots of little Phil Schillers running around inside your Mac waving their arms in the air going "Arrrrrrrrrrgh!".

    That's basically a Kernel Panic.
     
  8. lugesm macrumors 6502a

    lugesm

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    #8
    Once a year ! ! ! Gasp ! ! !

    I have owned a Mac for only one week.

    In 15 prior years of Windows use I never had a system crash; only read about the "Blue Screen of Death" on the Internet.
     
  9. TBi macrumors 68030

    TBi

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    #9
    Who said once a year? Apples rarely, if ever ,have a kernel panic. They usually do so for the same reason that windows has a BSOD, bad ram, bad CPU, bad drivers, user fiddling where they shouldn't, etc.
     
  10. twistedlegato macrumors 65816

    twistedlegato

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  11. peeaanuut macrumors 65816

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    #11
    I have had a couple in the past few days, but I think I was just doing waaaay too much. rying to encode a movie while burning a dvd, farting around with bit torrent and exporting from iPhoto. I jus dont do that many things anymore and it has been fine since.
     
  12. TBi macrumors 68030

    TBi

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    #12
    That shouldn't cause a kernel panic. There is probably a hardware fault somewhere in your laptop. That or the OS has an issue and should be reinstalled.

    Try opening two terminal windows and typing

    yes > /dev/null

    into both of them. This will stress the CPU and cause a crash if there is a problem.
     
  13. IJ Reilly macrumors P6

    IJ Reilly

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    #13
    Could someone please provide me with a reproducible or verifiable example of a kernel panic caused by an OS or software issue?
     
  14. TBi macrumors 68030

    TBi

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    #14
    I had kernel panics with a beta version of parallels. Can't remember which version though. That was a software problem.

    Also i had some before using software for my PDA. Can't remember the name of it right now and i don't really want to reproduce it again :)
     
  15. lugesm macrumors 6502a

    lugesm

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    #15
    I have not yet upgraded my memory from 1 to 2 or 4 GB, because I have been advised that bad memory can cause Kernel Panic. From the comments above, it appears this can be true. In fact, the Mac "expert" that advised me told me that it could happen even a year after the memory is installed because of semiconductor degradation or other aging problems.

    By the way, under what conditions would it be advisable to upgrade my NEW 24" iMac to 4GB rather than 2GB? Big cost difference, I know. I plan to run Parallels eventually when I am more experienced with the Mac.
     
  16. TBi macrumors 68030

    TBi

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    #16
    Bad ram can be replaced. Buy from a respectable outfit and you'll be ok.

    If you are worried about this then boot from the install CD into diagnostic mode after installing the ram. This will do a full check on the ram before you boot to OSX and potentially cause damage from a bad stick.

    As for ram going bad over time. Maybe in 10-20 years, your "expert" is talking out his back passage.
     
  17. IJ Reilly macrumors P6

    IJ Reilly

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    #17
    Not even in the interests of science? ;)

    Yes, I can well imagine kernel panics being caused by software which installs buggy kernel extensions, but this should be a rare cause. What I've seen even more rarely is a kernel panic situation fixed by reinstalling the OS.
     
  18. pprior macrumors 65816

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    #18
    I totally call BS on this. I used PCs for 20 years before moving to mac and I don't know ANYONE who didn't get a blue screen. I just don't buy it.

    I can't even begin to count the number of bluescreens I had. Most were driver related - usually some crappy creative labs soundcard or such.

    Anyway, I've had a total of 2 ocassions with my mac Pro since I bought it in January where a little circular message would pop up in the middle informing me my system needed to be restarted and the whole thing was locked up. I assume this is a Kernel panic. i think there was little eyeball looking logo.

    I've had more problems with an application locking up (typically a game like 2142) and then being stuck at a blue screen - I can find no equivalent to ctl-alt-del to bring up a tasklist and kill the hung process.
     
  19. jellomizer macrumors 6502

    jellomizer

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    #19
    The Operating Systems Kernel operates the same way a Colenal (Pun was intended) does in a military. It manages the whole computer and make sure the programs don't use a resource an other program is using. Or give a program enough memory to work but not hinder the rest of the system. Also it manages security and the such.

    So a Kernel Panic is when something happened to the kernel and forced it to exit, unexpected result from hardware, bug in the Kernel software that couldn't handel a request from a program. So because of the error the Kernal Errored out and quit. When a normal program does so the Kernel normally handles and and make sure your whole computer doesn't go down it usually frees up the memory and puts things back in place where it can be used again... But when the kernel exits there is nothing that can be done. There is no program telling the other programs that it is OK for them to go. So your computer is basicly frozen and the only way back is a system restart. Normally when a kernel panic occures it tries to give its final words like displaying that the Kernel Panic and dumping memory to the disk for debugging. Then it stops.
     
  20. jellomizer macrumors 6502

    jellomizer

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    #20

    Its doable. If the person has bought computers that used windows most stable drivers. Used programs that played nice with windows (not trying to override the kernel like some games do or even some other programs) Browsed safe internet sites and work cleanly. Then they could go without a kernel panic. But what normally happends is we let our guard down and overfill something, run the wrong program, cheap out on the hardware... Cause the BSOD
     
  21. r-sparks macrumors 6502

    r-sparks

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    #21
    Had a G4 iBook for two years, before getting an Intel C2D iMac Xmas 2006 and a MacBook a few months later. Upgraded the memory variously in all of them.

    I browse, word process, iTune, iPhoto, eMail, play Scrabble, run Windows in a VMWare virtual machine...

    Never, ever seen a kernel panic message. I'm actually curious as to what they look like. Once a year sounds like bunkum to me.

    I've never had OS X crash, in fact. Some of the iLife apps occasionally crap-out (iPhoto, I'm looking at you), but that's just a simple "This app has crashed—do you want to tell Apple?" message. The system doesn't come to a juddering halt.

    Never had Windows XP blue-screen, in fact, and I used that at work for many years. The fact is that modern operating systems are pretty stable.
     
  22. lugesm macrumors 6502a

    lugesm

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    #22
    pprior -

    QUOTE: I totally call BS on this. I used PCs for 20 years before moving to mac and I don't know ANYONE who didn't get a blue screen. I just don't buy it.

    Sorry to read about your bad experiences. I have no motive for BS here, just stating the facts.

    Having written that, I must say that I was a very conservative user, kept my machine uncluttered, never loaded questionable software or shareware.

    Just lucky, I guess. :)
     
  23. Buttercookie macrumors member

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    Jun 2, 2007
    #23
    IMO the only way to have that experience with windows is to not hook up internet service and not load any programs. I guess if you use notepad and use it like a glorified typewriter you may have not had a Blue Screen even then if you didn't reformat atleast once a year Windows likes to crap out.
     
  24. Bigtree thread starter macrumors 6502

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    #24
    What snob! You get-up on the wrong side of the bed???? Maybe you should go back to bed.
    I would rather ask here where most people give real answers.
     
  25. Coprolite macrumors member

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    #25
    I must admit that I have gotten the BSOD before. However, the great majority of Windows related crashes and lockups never quite went that far. In either case, the end result was the same...forced reboots and troubleshooting...

    As for a Kernel Panic, I really don't remember having one. I only know that two happened by reading the log file. Maybe my brain is developing some bad sectors. Either that or my efforts to overwrite traumatic past experiences with new data has been successful.
     

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