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I've been running Ubuntu 10.10 in a physical x86-64 machine. Today Update Manager reminded me that there are some updates to install and I confirmed the action. I should had read the update list but I didn't. I can only remember there is an update about cups. After the upgrading, Update Manager requires a restart and I confirmed too. But after the restart, the computer can't start up. There are errors in the console.

Begin: Running /scripts/init-premount ... done. 
Begin: Mounting root file system ... 
Begin: Running /scripts/local-top ... done. 
[xxx]usb 1-8: new high speed USB device using ehci_hcd and address 3 
[xxx]usb 2-1: new full speed USB device using ohci_hcd and address 2 
[xxx]hub 2-1:1.0: USB hub found [xxx]hub 2-1:1.0: 4 ports detected 
[xxx]usb 2-1.1: new low speed USB device using ohci_hcd and address 3 
Gave up waiting for root device. Common probles:
     - Boot args (cat /proc/cmdline)
        - Check rootdelay=(did the system wait long enough)
        - Check root= (did the system wait for the right device?)
     - Missing modules (cat /proc/modules; ls /dev) 
FATAL: Could not load /lib/modules/2.6.35-22-generic/modules.dep: No such file or directory
FATAL: Could not load /lib/modules/2.6.35-22-generic/modules.dep: No such file or directory ALERT! /dev/sda1 does not exist. Dropping to a shell! 
BusyBox v1.15.3 (Ubuntu 1:1.15.3-1ubuntu5) built-in shell(ash) 
Enter 'help' for a list of built-in commands. 
(initramfs)[cursor is here]

At the moment, I can't input anything in the console. The keyboard doesn't work at all. What's wrong? How can I check boot args or "root=" as suggested? How can I fix this issue? Thanks.

===============

PS1: the /dev/sda1 is type ext4 (rw,nosuid,nodev)

PS2: the /dev/sda1 can be mounted and accessed successfully under SUSE 11 SP1 x64.

PS3: From this link, I think the keyboard doesn't work because the USB driver is not loaded at that time.

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up vote 0 down vote accepted

It looks like it's not detecting your root partition (/dev/sda1), which is the partition that essentially contains your OS. (/)

The reason you can't input anything probably is because the console isn't loaded yet. (initramfs) somehow doesn't seem a proper console prefix to me but I might be wrong, you might want to give it some time to load.

However, I find it hard to believe that just a CUPS (Common Unix Printing System) update could cause this since CUPS is just the Linux print service.

When you boot your computer, the GRUB bootloader should give you a choice which kernel to use. See if there is a kernel that has a lower version than the one selected and see it that boots.

If it does, the kernel entry is probably faulty and won't load the proper drivers/modules for it to find your hard drive. Creating a new entry or rebuilding your kernel might work.

If that doesn't work, you might want to boot Ubuntu into recovery mode and see if you can access /dev/sda1 from there.

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Thanks BloodPhilia, you're right. the reason is about the kernel's reason although I don't know why it cause "not detecting root partition". I find in /dev/sda1 there are 2 kernel image, one for 2.6.35-22, one for 2.6.35-24. So I add a new entry for 2.6.35-24 in menu.lst manually, then try to boot in 2.6.35-24, it works. – Landy Jan 10 '11 at 3:18
    
@Landy great it worked! ;) – BloodPhilia Jan 10 '11 at 11:12
    
Sorry for accepting your answer to late. I just know I should do it after I get a right answer. :) – Landy Apr 21 '11 at 9:02

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