[allblue]

This morning I switched on my G4800 iMac (10.3.9) and went to put the coffee on as it starts up as I do most mornings. However when I got back there was a dark blue screen with the 'Kernel Panic' message. I switched off and on, and everything started up as normal. There hadn't been any problem yesterday, or when I closed down last night, and I haven't installed any new software for a while (and anything that needs an installer for even longer). What could have caused this? Do I need to run any utility as a consequence (DiskUtility or Drive 10)? because everything is working fine now.
History of Kernel Panics. This beautiful machine is three years old now and gets used nearly every day. In that time I have about twenty Kernel Panics, but seventeen of them have been directly caused by the POS drivers for my Alcatel Speedtouch ADSL modem, in other words this is only about the third or fourth time it has happened during normal operation, and I think, only the second on start-up, and none of those for ages. I'm not unduly concerned by this as everything is working fine now, but as I know little about what goes on underneath the GUI and also live in a country with almost zero Apple presence (Portugal), Kernel Panics do tend to give me brain panics! Any thoughts would be appreciated.

[osxrules]

I think the drivers for USB devices load at startup. I don't know why this is. There is an extensions folder in /Library for 3rd party extensions but they all install them into the system folder. So, a startup panic could have been your modem again assuming it was plugged in at the time.

I hate usb stuff for that. That's one reason I prefer having cable broadband because it uses the ethernet. As long as you don't have regular issues, I wouldn't worry too much. I got a kernel panic just through the week from using a set of usb headphones. I haven't had one for months.

[allblue]

That makes sense... Ceratinly the power light on the modem comes on almost immediately after switching on the iMac and as I said nearly every Kernel Panic I have had has been due to the modem drivers, otherwise (as you handle suggests osxrules) it is a rock solid OS. I have to install the drivers with an installer and it requires a restart which suggests it is interfering with the system... they really should make their drivers more stable shouldn't they? Unfortunately I do not have the ethernet option here, if I was twenty miles down the road in Spain it would be a different story...

[osxrules]

Check that you have the most recent drivers too:

http://www.speedtouch.com/support.htm

Upgrading the system might help actually. I installed a wireless Belkin usb device on my brother's old G3 imac with 10.3.9 and it works most of the time but it gave a kernel panic once.

My Mac Mini with 10.4.2 used different drivers and it hasn't panicked. Both times, it installed extensions into the system folder. I couldn't say a newer system would help for definite because I didn't test it enough and there are too many variables.

However, if you even got a wireless ADSL modem, that should fix your problem because you don't need drivers for the modem. You just buy a wireless device that supports Mac really well such as Apple's Airport card.

That way, the only drivers in use are those running the Airport card and they are designed to work well with OS X. The wireless modem just receives the signal from the Airport card. All you'd need to check is that they both support the same encryption.

Wireless is a bit expensive though and not 100% reliable.

Another option is to get a wired ADSL router. They have an ethernet cable that plugs into your machine so no drivers needed.

Or you could change your modem altogether and get something like this:

http://www.adslguide.org.uk/hardware.../q3/xmodem.asp

It's an ADSL modem that supports ethernet. I think that's probably the cheapest route as you can sell the modem you have. It would be more reliable that matching a router to your current modem too.