Really wierd computer slow boot at random
 

If I boot the computer it boots really really slow. I timed it. 40 minutes to completely boot FC4. When booted I run top. Top takes about 10-20% CPU to run. (which explains why everything is slow.)

If I boot with Knoppix off CD I get a screen saying knoppix tried to select an invalid video mode. So I select 80x50 characters. Then reset the computer and pull out the cd. (Before Knoppix even starts booting)

Then FC4 boots in about 1-2 minutes. Top takes about 0.3 %CPU. If I reboot FC4 I'm right back to the same problem as above till I boot with Knoppix.

I tried replacing the video card and it doesn't fix the problem. I've been endlessly changing settings in the CMOS to try to fix it. Nothing is working. The dmesg show nothing different between the two boots. nothing is different in the message log files. (I did diff on the output of both)

Any ideas where I should look for this problem? I'm assuming FC4 is making something stick. Which Knoppix corrects. Any ideas?


Thanks,
Michael

First of all when it takes 40 minutes to boot, you probably have problem with a particular service (and NOT a hardware resource). For example the nfs shares do take up a lot of time to boot if you have not configured it properly.
If you know how - follow the following steps
1)Boot into single user mode
2)remove the services that may be creating trouble
3)reboot and reconfigure the services.

The NFS could be part of it. But it doesn't explain the 5 minutes to bring up the udev or the 5-10 minutes on the initializing hardware (storage, network, audio, etc) All before it even mounts the hard drive.

Unless there is a service which loads at the same time as the FC4 kernel. (before it boots)

Michael

fixed it. I added mem=500M to the grub.conf. Not the system takes about 1-2 minutes to boot every time.

Can anyone tell me what this parameter does or why this fixes my problem?

Michael

it tells the kernel that the memory(RAM) in your computer is 500MB.
read the kernel docs.
Robin

Seemingly, because of some strange hardware problem or otherwise, the kernel failed to probe/find the exact amount of RAM your machine has. And so, it probably was working with very little RAM and that explains the 40 minutes boot !!

Passing the parameter mem=500M told the kernel that the amount of RAM you have is 500M and that resulted ....... !

Although, I do not know the reason why the kernel fails to find out the amount of RAM, I have come across forums with threads similar to this one.

Well done !! You figured it out (perhaps accidentally ? ;-) ) yourself and in such a short time.