Getting Grubby & Demystifying Linux Booting 105
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."
Redhat specific (Score:3, Informative)
Re:Redhat specific (Score:4, Informative)
It's also rather light on content. 3 pages to say "yeah, this runs, and a bunch of other stuff that I won't talk about happens".
This might have been useful in 1999.
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About then (or maybe a lot later) the only grub documentation was: GRAND UNIFIED BOOT LOADER - we rox and LILO sux. Thankfully there's a lot more than that now and even a man page (was "info" only for not invented here reasons for a while).
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You must be kidding
And yet the article claimsThe article won't help, however... It is not nearly detailed enough for learning anything.
Windows refugees (Score:5, Interesting)
Re:Windows refugees (Score:5, Insightful)
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And 152 days of uptime is nice. Winows folks would love to have that kind of reliability
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1. If no drivers crash.
2. If there are no security updates requiring a reboot.
There are probably more, but those two alone prevent that long an uptime.
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3. If explorer.exe doesn't crash and not unallocate it's memory (which I suppose could be taken care of by a third party shell, but most of them will end up pulling explorer up for something anyway , and a decent amount of them are unstable when run for a very long time, a way around most explorer crashes has been for me to check the little known box that will load another explorer process for every window t
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Actually, this Windows user prefers not to waste all that electricity having the computer sat switched on doing nothing while he's asleep, watching TV, out with friends, etc...
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Wikipedia in the vein is not funny, my parrot's tapeworm died that way!
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An easy way to record video and post to YouTube.
An EASIER way to make mp3s out of a CD (out of the box).
Distros defaulting to the obvious preferable applications: Thunderbird, VLC, etc.
Some more decent games besides Urban Terror and Emulators.
More and Better Hardware companies supporting Linux.
Easy and Fast Videoconferencing via speex and h.264
Not needing to configure Grub at all.
Also (in Ubuntu), not having an infinite list of growing kernels to choose show up in G
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That article was shit. If you think that was helpful then I guess the Joy of Sex was a real eye opener for you.
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We're refugees, not immigrants, you insensitive clod. We're gonna be requesting political asylum soon.
Re:Redhat specific (Score:5, Funny)
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It's all the fault of that screwy wabbit.
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do it from scratch (Score:3, Informative)
I always got annoyed about things that run on my computer that I don't know what it is, and if removing it would break anything. LFS clarified for me many dark-spots about the boot process. I even ran the installed system for almost a year, but it got harder to keep up-to-date with package versions, and I came back to using a normal distro.
Re:Redhat specific NO IT IS NOT (Score:1, Informative)
Bad article (Score:5, Informative)
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But seriously, it's not that confusing: BIOS finds and starts grub, which finds and starts kernel, which finds and starts init, which finds and starts everything else listed in the correct sets of
Re:Bad article (Score:5, Informative)
Slackware-based distros, for example, use runlevel 4 for X instead of RL 5. They also have *all* init scripts in
that's to say nothing of distros that aren't even using SysV init, like the current version of Ubuntu and anything BSD-based.
It was pretty obvious that the author hasn't done his research, and that it's a pretty poor attempt at explaining stuff. I was rather hoping for an article where the author would actually parse the output of dmesg and explain, line for line, what everything meant. That would actually be informative. Instead, he gave information that was specific to RedHat Linux, a lot of which doesn't apply to other distros. I wouldn't even be complaining so much, except that he didn't even bother to write it specific to the most popular Linux distro. RedHat was the most popular when I started with Linux, over a decade ago. These days, that crown belongs to Ubuntu. If you're going to write something distro-specific, at least write it for the most popular one.
Obligatory disclaimer: The last version of RedHat that I used was RedHat 6.0. When 7.0 came out, I switched to Slackware. I now use Zenwalk (slack-based, formerly MiniSlack, http://www.zenwalk.org/ [zenwalk.org]), having switched at Zenwalk 2.4. I have tried other distros, including Ubuntu, and still prefer Slackware-based distributions, and I find that the Zenwalk community and package management tools are the best of that breed.
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This one's [comptechdoc.org] a bit elderly, but I found it handy for wrapping my head around Linux.
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No Upstart? (Score:3, Informative)
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Re:No Upstart? (Score:4, Informative)
I [ubuntu.com] think [ubuntu.com] you [ubuntu.com] didn't [ibm.com] do your homework [ubuntu.com].
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This whole topic gave me the nudge to go back and read up on upstart. It really does have the potential to be either a colossal mess or a magical cure. I look forward to seeing how it plays out.
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Oh yes. Now that you say it maybe it is like that. Sorry Mr. Smith. I didn't mean to be mean.
Pathetic (Score:4, Informative)
The concept to write an article about the boot process actually sounds cool, seeing as how there is quite a bit text that whips by on start up which many (even long time) Linux users don`t understand.
This article however, was a really lame attempt to do so. It was very general, without even so much as a sample of text from dmesg. And what was there was very distro-specific. It just provided a quick over view of the major parts of the boot process, and didn`t even do that very well.
Anyway, as someone said before, don`t even bother reading TFA..
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To bad so many people will read this and end up with a biased understanding of the Linux boot process....
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What?
Am I supposed to do that?
I have just been responding to what I misread in the summary.
Someone should have told me when I joined, I never would have figured it out on my own... oh the wasted comments I have left.
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It may not bring "the average user", but it may help the curious yet non-power user be a little less afraid of Linux on the desktop.
For myself, I think I could surf such
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Without looking, I would guess the Gentoo Wiki. Even when I'm looking for information on other distros, Google often turns up hits to Gentoo Wiki.
(I also ran Gentoo for
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While I agree that the article is short on details, I would not characterize its content as pathetic. It is just an overview of the boot process for Redhat. It would be improved by adding links for more in depth information on runlevels and init.
By it being posted on Slashdot, it may help some of the Windows users who think Linux is hard to at least try a dual boot. If nothing else, the fact that Windows can only boot in Safe Mode or Normal with limited customization, while Linux has different boot loade
It's Web 2.0 (Score:5, Insightful)
Ever since somebody decided "Web 2.0" existed, there's been a big slew of these awful new "IT stuff" sites that look like they've been designed using a checklist of Web 2.0 mainstays and buzzwords. User ratings? Check. Submit news? Check. Blogs? Check. Annoying multipage articles? Check. Attention whoring abuse of social bookmarking sites at the end of every article? Check. More banner ads than content on any given page? Check. User comments? Check. Half of it is actually a decade old and was pioneered by Slashdot, but thanks to the magic of buzzwords, everything old is new.
And with all of this stuff in place, they invariably fail to even attempt the final hurdle: creating decent content. Instead of picking one of the two available routes (create good content vs Slashdot-style aggregation), they seem to like to go halfway, with awkward "stories" like this half-boiled Red Hat GRUB HOWTO masquerading as "Breaking News".
Sure, maybe these are probably all honest people trying to kick-start their journalism careers. But if so, what the hell are they doing throwing this crap around? Even Katz was more interesting than this trash.
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An Article about init (Score:3, Informative)
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It just seems to sit in experimental. The fact that sysvinit stays marked as required and tries to re-install itself and remove upstart doesn't help.
Grub2, on the otherhand, has been offered for the past couple months during installation.
Ubuntu's fast resume patch for grub (Score:4, Interesting)
[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.
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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
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What does Grub Offer that Lilo Doesn't (Score:1)
So what does grub offer? The Via K?800 problem has been unresolved over the last 5 years and there's no reason not to have fixed it by now. Hell if I was repurposing old windows machines to Linux, more then likely they'd have that damn chipset.
On the new Intel chipset, as stated grub couldn't even finish booting. Wheres the kernel couldn'
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Grub couldn't complete booting on a system with either SATA or IDE drive installed and yet it could install itself into the mbr from a running kernel
The VIA K8 chipset problem is a known issue with the splash images that's over 5 years old and still unsolved
So the question once again What Does Grub offer over Lilo?
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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.
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Lilo probably overcame this a while ago but there is also problem reading beyond 1024 cylinders
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Welcome to 2000!
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Oh YEAH? Well LILO has a bigger ... feet!
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That means that as long as grub works at all, you can load and boot any kernel from any disk with a FS grub can recognize. This is really great for the cases where for example there's a typo in the configuration and the kernel's name is wrong in the file, or it's been mistakenly deleted, but there's an old kernel on the disk not listed in the config file.
LILO, on the other hand relies on a map file that tells it where on the disk the kernel is. That mean
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LILO copies a kernel image to its boot area. It doesn't matter if you change the kernel on the hard drive, because LILO's installed image won't change until you invoke the "lilo" command. I've actually seen LILO successfully boot a kernel and initrd (which panicked) after I had formatted a drive and removed all of the partitions, because I hadn't bothered to wipe the MBR.
With GRUB, however, it's live. If you make a change to your menu.lst file, that change will take effect immediately
Re:What does Grub Offer that Lilo Doesn't (Score:4, Informative)
No, it doesn't. You can read the LILO technical documentation if you don't believe me.
The fundamental thing about LILO is that unlike Grub, it's incapable of actually reading the filesystem the kernel is on. The way it works is that the boot sector contains the location of the map file, and the map file contains the list of sectors that make the kernel. There's no "boot area" as such. It's trivial to verify that the map file isn't the kernel, as it's tiny (78KB on one of my boxes)
The reason LILO booted for you is simply because a format didn't overwrite the data areas of the disk. Since LILO doesn't read the FS itself, it doesn't matter to it that all the metadata is gone. So long the boot sector is there, the map's data is there (even without metadata indicating the filename, etc), and the kernel's data is there, it'll boot.
LILO however will completely mess up if you are unlucky. Overwriting the kernel without calling "lilo" afterwards might work if it just happens to write over the same sectors and uses the same number of them. Or maybe the new kernel is written somewhere else entirely, in which case you'll boot the old kernel and it'll break later when something reuses the space taken by the old version.
The problem with LILO is that you can screw it up without touching LILO itself. For example, delete the active kernel. It'll probably work anyway, right until something reuses the space previously taken by the kernel. Then boom, doesn't work anymore. With grub it doesn't matter if you make a bad config file, or delete a needed kernel. So long there's a kernel on disk, grub can boot it.
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LILO copies a kernel image to its boot area.
No, it doesn't. When you run lilo to install a kernel, it finds out which set of physical disk blocks contain the kernel image and stores the address of those blocks in the boot area. At boot time, it loads from that address. Note that if your file system were in the habit of moving files around, it might break LILO.
I've actually seen LILO successfully boot a kernel and initrd (which panicked) after I had formatted a drive and removed all of the partitions, because I hadn't bothered to wipe the MBR.
It didn't matter that the partitions were removed because LILO doesn't know or care about partitions. It was able to load the kernel because the disk blocks containing the kernel hadn't
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As to grub failing to boot on my shiny new DQ965GF with only SATA, the error there was couldn't find bootable disk and yes I'm using AHCI mode only. No IDE emulation (it's emulation after all). Grub simply couldn't find either h/sd0,0 to boot from
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Anyone can answer this better? - I'm no bootloader expert
Re-writing the boot-record (Score:2)
Sad little article (Score:2)
- the standard way, from the boot sector of your hard drive
- the live-cd way, from an eltorito image on a cd-rom or dvd-rom
- the original way, from a floppy drive
- some machines let you boot from a zip drive
- from a usb key, which could be any of the above under the covers
- over the network, using pxelinux
- out of rom
This article has no interesting content whatsoever.
Linux users can boast long times between reboots (Score:2, Insightful)
Look kids, it's time to grow out of willy-waving contests about how long you can keep it up, and turn the ****ing thing off when you're not using it.
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Climate Changes? Ask me if I Care (Score:2, Insightful)
willy-waving
bragging about uptimes even though I leave my system on 24/7. It's because I'm running 2x Folding at home Clients.
As to climate change, hell yes we're suffering climate changes but are the man-made or because we've entered the 50 year increased solar activity period of the 100 year cycle? The other question is who pays for the demanded changes and will they do any damn good? The damn research has gone about finding a solution the wrong way.
Instead of looking at how to cut energy demands by
gettin
Re:Linux users can boast long times between reboot (Score:3, Insightful)
what a British geeza would say (Score:1)
What's the point of this article?? (Score:1)
Do it yourself (Score:1)
All you really need is busybox(gnu tools), the c library and linux kernel. It doesn't do much, but it will help you learn how it works.
It's a lot more interesting than reading that article.
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Huh? This is old news, and hardly technical at all -- by my standards, anyway.
Now, whitepapers, the ACM, IEEE, RFCs, etc... those are technical.
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Isn't Eloi Aramaic for 'father'? o_0
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