Getting Grubby & Demystifying Linux Booting

davidmwilliams writes "Linux users can boast long times between reboots, but even so, the startup screens will grace your display at some time. Here's just what your computer is doing during this process, what the messages mean, and how you can take control."

Comments

Windows refugees

[Harmonious Botch]

The article won't help, however... It is not nearly detailed enough for learning anything. For the recent immigrants from Windows, it is a great roadmap.

Ubuntu's fast resume patch for grub

[schwaang]

By way of making lemonade, here's a post by an Intel engineer to ubuntu-kernel-devel about a proposed grub patch that would make resuming from hibernation much faster:

Below is the work theory of our "grub fast resume" patch
The normal swsusp2 resume process is:
"grub" -> "kernel" -> "initrd" -> "resume from the hibernate"
Our "grub fast resume patch" can work as below:
"grub" -> "resume from hibernate"

Our "grub fast resume" patch can resume the saved hibernation image from
grub directly that will save much time to load and run kernel and
initrd. The patch does not change any kernel code.

[I use hibernate on Fedora all the time, so I'd love to see a patch like this go in to Fedora's grub. Thing is, the patch is apparently based on swsusp2, and I'm not sure Fedora's kernel uses the swsusp2 version of hibernation.]

In a reply to the post, a debian guy points out that grub is legacy at this point, and that they are looking to move to grub2.

Re:Ubuntu's fast resume patch for grub

[pintpusher]

That's a pretty cool little bit. It only makes sense, if the entire system is imaged onto the harddrive, why not just pull up that whole image from the bootloader and run it from there. Obviously there's more to it than just that, but still its a concept that makes sense.

I see potential problems though if you've got changing hardware. By loading the kernel, you can reprobe the hardware (haven't watched a resume in a while to see if it actually does, but at least the mechanism is there). If you just drag in the whole image and restart execution one potentially changed hardware, that's a problem. But then I don't know whether hibernate handles changing hardware very gracefully anyway. blah blah blah rambling.

Re:What does Grub Offer that Lilo Doesn't

[VGPowerlord]

I'm sure I could go into more detail by doing a little research, but in short:
GRUB is intended to be more generic than LILO and thus runs on more OSes and platforms. The developers probably got disgusted with dealing with LILO, SILO, PALO, boot0, etc... on different machines.

Re:Linux users can boast long times between reboot

[Ant P.]

That would be a GREAT idea, if only you showed us your secret way of resuming from cold boot within 0.5 seconds when the machine recieves a tcp syn packet on port 80.