Who Is Kernel Panic, And Why Is He In My Mac? Apple Posts Mac OS X TIL

With the first release of Mac OS X, a shocking and surprising thing has happened for some Mac users. Their beautiful Aqua GUI has collapsed into a pile of white text on a black background, with a message of some sort talking about Kernel Panic. Who is this Kernel Panic, and why is he in your Mac? Apple has posted a Technical Info Library (TIL) article on this issue to help explain this issue to Mac users, but the TIL article actually asks more than it tells.

We are going to help a bit. A kernel is what an operating system is built on top of. It handles all the ugly low level things like talking to the hardware. Mac OS X is built on top of a version of Unix called Free BSD and uses the Mach Kernel (check out this interesting article from ZDNet from February of 1997 on the Mach Kernel being chosen for Rhapsody, the precursor to Mac OS X. In any event, when one gets a kernel panic, oneis computer is severely choking on its instructions and simply has to call it quits. This could happen with the old Mac OS too, but we usually saw that as some form of freeze without any ugly text cluttering up our screens. When it happens in Mac OS X, you get the text. Itis ugly, and it is most un-Mac-like.

According to Appleis TIL article:


UNIX-style operating systems (such as Mac OS X 10.0, Mac OS X Server, AIX, and A/UX) may experience a type of error called a "kernel panic," which may provide information useful for software developers.


A kernel panic is a type of error that occurs when the core (kernel) of an operating system receives an instruction in an unexpected format or that it fails to handle properly. When this happens in either Mac OS X 10.0 or Mac OS X Server, white text on a black background is drawn on top of the last video image on the monitor before the error occurred. The text of a typical panic might contain something like this:

"Unresolved kernel trap(cpu 0): 0x300 Data access DSISR=0x40000000 DAR=0x0000006c PC=0x06d77510 MSR=0x00009030

generating stack backtrace prior to panic:

backtrace: 0x06d77510 0x0002a1fa 0009d1ef 00099440 012f4102 kernel modules in backtrace: com.apple.filesystems.cddafs(1.0) @ 06d75000

Memory Access Exception(1,0,0) Waiting for remote debugger connection"

Apple is requesting that users who get this message report it to Apple, and they offer detailed instructions for how to do so, and what information to get. With Apple working hard to make Mac OS X all that it can be, we encourage you to take the time to do so if at all possible.

Apple has provided a screen shot of this in action in the TIL article, so go and check it out. You can also find more information than we quoted above in the article. Lastly, there is more information on reporting this to Apple in a related TIL article.