[CentOS] Why noapic acpi=off on new Centos 4.6 system?

Craig White craigwhite at azapple.com
Thu Nov 20 14:16:49 UTC 2008

On Thu, 2008-11-20 at 10:43 +0000, Tony Mountifield wrote:
> I just installed CentOS 4.6 (because I had 4.6 media handy) on a new
> system, which has a SuperMicro PDSMi mobo with an E4600 CPU.
> I then did yum update to get to 4.7, although I don't think that's
> relevant to my query.
> I wondered why "shutdown -h" would not power down the system. I then
> also discovered that the soft power button did not initiate a switch
> to runlevel 0 to do a controlled shutdown.
> When I looked in grub.conf, I discovered that the installer had included
> the boot parameters "noapic acpi=off". I removed them and rebooted, and
> then found that both soft shutdown from the power button and the final
> poweroff worked fine. I haven't stressed the system yet, but it seems
> to boot and run fine.
> My question is (at last): why did the installer decide it necessary to
> include "noapic acpi=off"? Previous installs of CentOS on other hardware
> have not done that.
I don't believe that anaconda would do that on its own.

It would however, append any kernel options that you used when you
booted the installation disk so that's the likely place where it came


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