Cause of Kernel Panics ?

[Washac]

Hi All


It seems that when people talk Kernel Panics on forums that I visit everybody says they are caused by hardware. Now I am confused by this as yes
as people say KPs can be caused by hardware, but surely badly or incorrectly written software can also cause KPs, as in badly written Kernel extensions
are also a cause are they not ?

I am trying to get to the bottom of all the Kernel Panics people are getting on Mac Pros, because all these reports seem to have appeared since Snow Leopard
raised its ugly head.

 

[spinnerlys]

A "kernel panic" may occur when the core (kernel) of an operating system receives an instruction in an unexpected format, or that it does not handle properly. A kernel panic may also occur when the operating system is not able to recover from a different type of issue. A kernel panic can be caused by damaged or incompatible software or, more rarely, damaged or incompatible hardware.
via http://support.apple.com/kb/HT1392

In short, the kernel panics, and as the kernel is based on software, the panic relates to software, most of the time.

http://en.wikipedia.org/wiki/Kernel_panic
http://en.wikipedia.org/wiki/Kernel_(computer_science)

 

[old-wiz]

Kernel panics can be caused by software or hardware. Software only does it when you are in the lower rings. Usually in the user level it just sends the program down.

 

[Washac]

A "kernel panic" may occur when the core (kernel) of an operating system receives an instruction in an unexpected format, or that it does not handle properly. A kernel panic may also occur when the operating system is not able to recover from a different type of issue. A kernel panic can be caused by damaged or incompatible software or, more rarely, damaged or incompatible hardware.
via http://support.apple.com/kb/HT1392

In short, the kernel panics, and as the kernel is based on software, the panic relates to software, most of the time.

http://en.wikipedia.org/wiki/Kernel_panic
http://en.wikipedia.org/wiki/Kernel_(computer_science)

Nicely answered

So the people I read about who have had most parts of there Mac Pros replaced and still get the Panics points towards possible software problems then ?

 

[Mumford]

Nicely answered

So the people I read about who have had most parts of there Mac Pros replaced and still get the Panics points towards possible software problems then ?

Unfortunately it's not that easy. It would seem obvious that a common factor such as an application (regular user level apps like Mail or Safari) would be the culprit. The reason they are almost never blamed for KPs because they just don't reach down far enough into the kernel. Usually, the app will just crash.

In my experience, device drivers are by far the mostly likely software cause of KPs. They reach deep into the kernel. And they are very frequently written by third parties, so they're sometimes not up to usual coding standards.

But you can only blame the drivers here if these Mac Pro owners also own a lot of the same devices (printers, cameras, scanners, etc). The obvious test is whether the system will KP under regular usage with no devices plugged in.

 

[old-wiz]

Unfortunately it's not that easy. It would seem obvious that a common factor such as an application (regular user level apps like Mail or Safari) would be the culprit. The reason they are almost never blamed for KPs because they just don't reach down far enough into the kernel. Usually, the app will just crash.

In my experience, device drivers are by far the mostly likely software cause of KPs. They reach deep into the kernel. And they are very frequently written by third parties, so they're sometimes not up to usual coding standards.

But you can only blame the drivers here if these Mac Pro owners also own a lot of the same devices (printers, cameras, scanners, etc). The obvious test is whether the system will KP under regular usage with no devices plugged in.

Excellent points. Applications crash themselves, not the system. Drivers that reach down low tend not to be coded all that well. Usually the 3rd parties are happy to just get the driver working reasonably well. I don't think they take the time to test with a variety of OS versions or systems.