将CentOS5.5安装到自己机柜的主机板上，安装过程还是相当顺利的，不过reboot以后，就出现了下列问题：
Kernel panic - not syncing: cannot execute a PAE-enabled kernel on PAE-less CPU
貌似我主机板地CPU不太给力呀。
解决的方法找到了一个：(网上的一位仁兄说是解决了，不过我的照例不行)
就是在开机进入的时候进入命令行界面：（添加下面粗体显示的部分）
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Fedora Core (2.6.18-1.2798.fc6)
root (hd0,0)
kernel /vmlinuz-2.6.18-1.2798.fc6 ro root=/dev/VolGroup00/LogVol00 swiotlb=force
initrd /initrd-2.6.18-1.2798.fc6.img
参考资料：http://www.dharwadkar.com/weblog/fc6_kernel
The Fedora project released their newest offering of the linux operating system last week. Roughly 7 months after their last release of Fedora Core 5 which is phenomenal as compared to "You Know Who". The cumulative upgrade is also good apart from the eye-candy changes with respect to the content and applications included in the OS package. The newer kernel is XEN enabled by default. I understand that XEN was included in Fedora from its Core 3 release, but I never really paid attention to it.
This time it caught my attention during installation with the application support & inclusion to XEN virtualisation. It caught more than my eye when the computer refused to boot up. FC6 uses a PAE (Physical Address Extension) enabled kernel (version 2.6.18-1.2798) and somehow it fails to identify the limitation of the CPU that it is being installed on if the CPU does not have PAE. On booting, the kernel went in to panic with the following message
KERNEL PANIC: Cannot execute a PAE-enabled kernel on a PAE-less CPU!
I tried really hard to recover from this. Even reinstallting the OS and going into GRuB command line to try and load another kernel. But it failed. I could install FC5 and then upgrade to FC6 from there without any issues. The FC5 and earlier versions do not enable PAE. I am yet to check out how FC5 would behave if I put in the same PAE enabled kernel on it. Probably it would faile too.
Anyway, I did not like the idea of giving up on solving this and upgrading from FC5 to FC6. Because, if this is a kernel issue, then I would definitely face this issue sooner of later when I upgraded my kernel so I got books from the library and search on the internet for whatever I could for the kernel and the bug (?) that was troubling me. On searching exhaustively with no results, I finally found something which I felt would work. I knew that I had to set a kernel option. But which one and what?
I found one list on XEN which talked about the same issue that I was facing and it noted that a workaround to the problem I was facing was to use
swiotlb=force
as a kernel parameter when booting. Although it talks about DomU, I was ready to try it on my computer. So I started the installation in rescue mode and at the kernel prompt, I gave this as a kernel parameter and the kernel did not panic. The FC6 went through first boot steps and got me to configure everything and then promptly hung.
It took a reboot to get the computer back on track and start working smoothly. After that it has been working quite nicely and I have done some testing on it that I will post here.
I will also post a detailed installation write-up here in the Technology section.
后面也参考了一些关于PAE的资料，挺有帮助的：
http://www.linuxquestions.org/questions/linux-newbie-8/pae-enable-618992/