My computer is an iMac rev B. that has been plauged by the PSU issues that have just had an extended repair announced. I'm going to take it in for that after my uni exams are over, in a few days.

Unfortunately, since yesterday it has now stared to kernel panic, it's giving me a "Disc Access" error or something.

I'm running 10.4.7 and have the original 512 ram plus another 1gb that has been in there and running fine for almost a year. It has never kernel paniced before yesterday. No new sftware I can remember either - i've been pretty much swamped with studying for uni exams.

Anyway, thanks for anyones help, heres the log of the most recent one:

Unresolved kernel trap(cpu 0): 0x300 - Data access DAR=0x0000000000000034 PC=0x000000000073570C
Latest crash info for cpu 0:
Exception state (sv=0x3A1E4780)
PC=0x0073570C; MSR=0x00009030; DAR=0x00000034; DSISR=0x40000000; LR=0x00735664; R1=0x2217BB50; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x00735664 0x0073C8F4 0x0073DF44 0x00731A84 0x00740E80 0x00740D70
0x007253C8 0x00749CF0 0x0003C744 0x000A9914
Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.AppleAirPort2(404.2)@0x706000
dependency: com.apple.iokit.IONetworkingFamily(1.5.0)@0x64a000
dependency: com.apple.iokit.IOPCIFamily(1.7)@0x45d000
Proceeding back via exception chain:
Exception state (sv=0x3A1E4780)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x39ECB780)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

Kernel version:
Darwin Kernel Version 8.7.0: Fri May 26 15:20:53 PDT 2006; root:xnu-792.6.76.obj~1/RELEASE_PPC
panic(cpu 0 caller 0xFFFF0003): 0x300 - Data access
Latest stack backtrace for cpu 0:
Backtrace:
0x00095718 0x00095C30 0x0002683C 0x000A8404 0x000ABD80
Proceeding back via exception chain:
Exception state (sv=0x3A1E4780)
PC=0x0073570C; MSR=0x00009030; DAR=0x00000034; DSISR=0x40000000; LR=0x00735664; R1=0x2217BB50; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x00735664 0x0073C8F4 0x0073DF44 0x00731A84 0x00740E80 0x00740D70
0x007253C8 0x00749CF0 0x0003C744 0x000A9914
Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.AppleAirPort2(404.2)@0x706000
dependency: com.apple.iokit.IONetworkingFamily(1.5.0)@0x64a000
dependency: com.apple.iokit.IOPCIFamily(1.7)@0x45d000
Exception state (sv=0x39ECB780)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

Kernel version:
Darwin Kernel Version 8.7.0: Fri May 26 15:20:53 PDT 2006; root:xnu-792.6.76.obj~1/RELEASE_PPC
*********

Umm no, its 0x300 - Data access not Disc Access.

By chance do you happen to use your airport wireless card, or is the machine connected via ethernet to a device which gets it onto the internet.

It's connected to ethernet, but I have internet sharing on to my powerbook through airport in the same room.

Internet is through the ethernet, that is into the university network,

Thanks for the quick reply

How often is the crash? is it within hours of a restart? If so, disable airport to confirm if in X hours time it does or doesn't crash again.

It looks to be related to the following in memory;

Kernel loadable modules in backtrace (with dependencies):
com.apple.iokit.AppleAirPort2(404.2)@0x706000
dependency: com.apple.iokit.IONetworkingFamily(1.5.0)@0x64a000
dependency: com.apple.iokit.IOPCIFamily(1.7)@0x45d000

You could always grab the last update for airport and apply it to see if that too makes a difference.

The first 2 panics happened within about 1 hour of waking from sleep, the third being within an hour of a restart.

I'm not getting any airport update in software update, should I just go ahead and get the 10.4.8 update?

I wouldn't say go 10.4.8, unless you have a backup of the system. Maybe just disable airport for a day and see if it happens again. Otherwise manually goto apple site to determine what airport updates have come out previously, match to your current version and reinstall it. Then with airport on see how it goes.

It might not be related, but several things worth doing to determine if it is related.

When you bring your machine to Service Centre for PSU replacement remember mention the above problem so they can look into it. Do as purana suggest, turn AP off see what happen, boot from FW drive with AP on see what happpen to narrow down if it really is a hardware related issue.

Regards

vanlan2010

For the past 3 weeks I had been running with AP off and got no kernel panics,

Now, instead of sharing my internet via AP, im just connected to airport for internet, and have been for a few days, without any problems.

I guess it might be something to do with sharing the internet?
I don't know, I'll mention it to them when I take it in for the PSU.

Thanks heaps for the help purana and vanlan, i'll post back if theres any more resolution

Have you tried with FW drive to test the AP. that would help narrowing down the issue. In your case probably either Airport card or logic board need to be looked at. but I am sure the Apple Centre will fix that for you if your machine is still under warranty.

corupt memory (ram) me thinks.......

as even minor RAM errors can lead to KP's under certain conditions which you may have changed.

Rember - http://www.macupdate.com/info.php/id/15837 (GUI)

Memtest - http://www.macupdate.com/info.php/id/15837 (CLI)