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Re: kernel panics and nvram issues
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Re: kernel panics and nvram issues



Hi David,

On Feb 9, 2005, at 10:21 AM, David Osguthorpe wrote:

On Tue, Feb 08, 2005 at 03:12:11PM -0800, Shantonu Sen wrote:

You are most likely running the nvram(8) commandline tool and not
rebooting. The core dumping settings will not be honored (they are only
parsed at startup) and the settings will not be preserved.



Is there no way to force the nvram update without rebooting?

The issue is not that NVRAM requires a reboot to be changed. It doesn't. The NVRAM has indeed been updated once you've run the nvram command.


The issue is that the kernel only reads the changed variables out of NVRAM at boot time.

Anybody know if the kernel hooks in the IOKit for the NVRAM allow
for the creation of such a program?

Is the NVRAM memory mapped into the kernel such that the bsd kvm_read/kvm_write
calls can be used to update the NVRAM?

Neither of these will affect when the kernel will next read NVRAM.


It makes for difficult cluster management if you have to reboot the nodes just to udpate the nvram variables

A valid point. But if you've panicked, you have to reboot anyway. You can save one reboot by updating NVRAM using the Open Firmware UI, but that requires you to be physically present at the server. There are a few Technical Q&As showing how to update the config variables using the OFUI.



David

--gc __________________________________________________________________ Garth Cummings Apple Developer Technical Support email@hidden

http://developer.apple.com/technicalsupport

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References: 
 >kernel panics and nvram issues (From: David Osguthorpe <email@hidden>)
 >Re: kernel panics and nvram issues (From: Shantonu Sen <email@hidden>)
 >Re: kernel panics and nvram issues (From: David Osguthorpe <email@hidden>)



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