Help! My Linux won't boot.

Pre-kernel

LI (on boot)

(or similar) - Lilo is not correctly set up. (For example, issues with old versions of lilo above block 1024 of the disk drive). See LiloErrorCodes.

;Loading Linux.......... Uncompressing the kernel. (stop) :

1. Are you using an InitialRamdisk? (initrd?) If so, do you have CONFIG_BLK_DEV_RAM and CONFIG_BLK_DEV_INITRD enabled in your kernel?
2. The kernel was compiled for a different architecture - for example, it has optimisations for AMD chips that don't work on an Intel chip, or vice-versa. If you changed the architecture of the kernel config (well, for kernel v 2.4 at least), you need to do a make clean afterwards, otherwise some object files that should be re-compiled aren't.

;GRUB <blinking cursor>: GRUB is unable to load it's first stage loader, use a rescue disk to start the machine. Re-install grub.

;I get the grub command prompt instead of my menu but if I type in "configfile /grub/grub.conf" the menu loads: This may occur with a Mirrored SoftwareRaid setup. Reconfigure your grub.conf file and remove any reference to a root (*) device.

install --stage2=/boot/grub/stage2 (hd0,0)/grub/stage1 (hd0) (hd0,0)/grub/stage2 p /grub/grub.conf install --stage2=/boot/grub/stage2 (hd1,0)/grub/stage1 (hd1) (hd1,0)/grub/stage2 p /grub/grub.conf quit

NB: This assumes a seperate /boot partition ;I'm having the same problem, but I'm not using RAID or anything...: From all the research I've done, it seems like problems of this sort are always caused by grub.conf mistakes. Mine seemed to be OK though, but I was still seeing problems. I noticed that when I ran

setup (hd0)

at the grub prompt, it mentioned a file called menu.lst . I renamed grub.conf to menu.lst, and things are now working! Apparently there may be multiple default filename possibilities for the GRUB menu file.

During kernel bootup

"ESR value before enabling vector: 0000002"

My machine (kernel 2.4.21) hung after printing this. (Athlon 2000 XP on an AD77 motherboard (KT400)). It is caused by APIC support in the kernel. Booting with the "noapic" kernel flag didn't fix it (although it made the machine go into an infinite loop printing an error about apic on cpu 0). Recompiling the kernel without APIC support resolved this.

Starting services

modprobe - Cannot find module char-major-??

Devices in Linux have major and minor numbers (unless you use the newer DevFs) Devices need to be implemented by the Kernel, either compiled in directly, or via a loadable Module. For example, serial ports are on char-major-4; see "ls -l /dev/ttyS0":

crw-rw---- 1 root dialout 4, 64 Feb 10 1998 /dev/ttyS0

major ^ ^^ minor

A common problem char-major-10 is misc devices such as psaux, watchdog, apm and nvram - "cat /proc/misc" should list the ones you're using. You will probably need to do some configuration in /etc/modules or /etc/modules.conf(5). Normally these messages don't cause problems later in life, but it's nice to have them cleaned up.

The allocation of each number to its respective device can be looked up in the file /usr/src/linux-your_kernel_version/Documentation/devices.txt, provided the kernel sources have been installed. In this file you can find out what device and module are affected. It does not have to be an error, but perhaps only information about the module not having to be loaded any more because it is already loaded or is not required.

grep char-major-10-135 /etc/modutils/arch/i386

That'll tell you what module you're missing.

• char-major-6 is the parallel port and can be fixed by compiling CONFIG_PARPORT=m.
• char-major-10-135 is the Enhanced Realtime Clock and can be fixed by compiling CONFIG_RTC=m.

See KernelErrorMessages for more information about missing modules.

Runlevel 2 and beyond

Loading syslog... (5 minute pause)
Loading MTA... (5 minute pause)
Loading apache...failed

Your problem is DNS, or the lack thereof. These services will all want to look up names in their configuration (normally your local machine name) and will be taking a month of sundays to time out as a result. Confirm this by typing 'host mydomain.tla' at the root prompt.

A good solution for this is to make sure that your /etc/hostname file (which is set using hostname(1)) also appears in your /etc/hosts file, like such:

127.0.0.1 localhost full.local.domain.name alias1 alias2

Eg:

127.0.0.1 localhost firewall.wiki.invalid firewall

(Remember, /etc/hostname should contain the shortened version of the name, 'firewall', not the FQDN), and the first name for 127.0.0.1 in /etc/hosts should be 'localhost'

I've added some other grub-specific tips under GrubNotes, where do people think they should go? Merged into here? Have the Grub specific points merged back into GrubNotes? --DanielLawson

GrubNotes belong in GrubNotes, I think. There should just be a pointer here, like "GRUB might be unable to find its config file. See GrubNotes.". --AristotlePagaltzis