Anatomy of the Linux Boot Process

Donna writes "This article discusses detailed similarities and differences involved in booting Linux on an x86-based platform (typically a PC-compatible SBC) and a custom embedded platform based around PowerPC, ARM, and others. It discusses suggested hardware and software designs and highlights the tradeoffs of each. It also describes important design pitfalls and best practices."

Comments

The good thing about Linux

[X43B]

What I like about Linux is never having to reboot except when it is time for a kernal upgrade. :)

Re:The good thing about Linux

[Claire-plus-plus]

What I like about Linux is never having to reboot except when it is time for a kernal upgrade. :)

Or hardware installation :)

Re:The good thing about Linux

[Anonymous Coward]

Or lowmem fragmentation/exhaustion. :)

Or a process stuck in I/O wait. :)

Or NFS gets confused. :)

Humility and knowledge of one's own weaknesses please!

Re:The good thing about Linux

[MikeCapone]

That is a good point, but it doesn't mean that the boot process can't be sped up quite a bit.

It would especially be useful on laptops, or for people who like to save electricity by shutting down their computers when not in use.

Re:The good thing about Linux

[God! Awful 2]

That is a good point, but it doesn't mean that the boot process can't be sped up quite a bit. It would especially be useful on laptops, or for people who like to save electricity by shutting down their computers when not in use.

It would probably be most useful for the Linux kernel developers themselves.

-a

Proof reading?

[FyRE666]

They could have at least made sure the arrows on the diagrams were round the right way!

acronymfinder.com didn't help

[Anonymous Coward]

what's SBC? Single Box Computer? Server? System? what?

Speaking of linux booting...

[saskboy]

I've always found it disconcerting that a verbose boot is given by default. Before Linux goes main stream on the home desktop, the distros ought to slap a plain progress bar with a pretty picture [ie. Windows clouds or logos] and not show verbose details unless something is wrong with the boot, or unusual.

Re:Speaking of linux booting...

[supercowpowers]

After struggling with making my grandparents computer work with the Windows ME "recovery cd" that came with the computer (they didn't tell me I was going to be working on it, and didn't have the best of resources at hand...), I finally decided to just bite the bullet and install Debian and Gnome on it.

I know, I know, Debian isn't exactly your "grandmother's distribution", but the distro in question is pretty irrelevant once I get to the point.

Anyway, I set it up so they basically couldn't screw it up. They don't know the root password, GDM is set to automatically log in their user (yes, their, hilarity would ensue trying to get them to understand the concept of users) on boot, and the desktop has I think 5 icons, "user's home", "Computer", "Pogo Games" (they love this for some reason), "E-Mail" (evolution), "Internet" (loads google in firefox), and "Trash".

They had to learn very few things to use this system, mainly what the icons do (which is easy because I made them visually huge and self explanatory), and how to shut down (Actions menu, not the Start menu)

Some other measures I put into place, like making a backup of /home so I could log in remotely and fix it (I had to do this once, because one day the icon for pogo games magically disappeared, even though they "Didn't do anything, I swear!"), but this is really turning rambly really quick...just to give you an idea of how idiot-proof the thing is.

They haven't had problems with it in about 2 months (since I installed it). Their usage is very basic, and this configuration serves them very well, since I can control the interface to be much less full of surprises than Windows.

So the world is all well and rosy...well...not quite...

I took no measures to clean up the default boot process, so it still outputs 'garbage' like

APM Bios version 1.2 Flags 0x02 (Driver version 1.2)
Entry f000:c64e cseg16f000 dseg f000 cseg len ffff, dseg len ffff
Connection version 1.1
AC off line, batter status high, battery life 82
[and so on...]

It fills the entire screen, and scrolls by so fast they couldn't comprehend it even if they knew what it all meant.

So I've counted about 5 times so far where my grandmother asks something like, "Now, is all that writing going to come up for good now?" It really, deeply bothers them to see all that as opposed to a pretty Windows logo. Not that I blame them.

So, that progress bar might be 'boring' to you, but it's blissful simplicity to somebody like my grandparents.

(FWIW, I prefer to see it all on a 1024x768 framebuffer, because I want to know when something is configured wrongly but can still pass that stage failing silently)

Re:Speaking of linux booting...

[mickwd]

"It will zip up to a point, then spend 95% of the time stuck there, and then zip to the end."

"On a somewhat unrelated note, I have also not figured out why Mandrake 10.1 takes far longer to boot up on a much more powerful computer than my Mandrake 10.0 system."

Somewhat unrelated ???!!!

Why don't you try pressing Escape just before the progress bar gets stuck, and find out which particular part of the boot process is causing all the delay. Mandrake may well be trying to set up some service or some piece of hardware that you don't actually use. If so, you can remove the item in question from you setup configuration. This probably explains why Mandrake 10.1 boots slower than 10.0 for you.

Re:Arrows

[teknomage1]

Tradition! Seriously though, BIOS code is very old and designed to provide for the least common denominator.

Re:Arrows

[Apreche]

If the most popular OSes out there are taking care of HW at the high level, why haven't BIOS makers taken advantage of this to reduce their workload?

Because if you buy a motherboard and the BIOS on it makes it so that the computer will only work with Windows XP, server 2k3 and linux kernel 2.4+ people will be pissed. Some people might still want to run DOS, OS/2, Windows 95/98, kernel 2.2, or some other old busted operating system. It's there for that reason. With a linux bios your computer can pretty much only run Linux. Which is fine if that's all you want to run.

Oh, and BIOS makers don't have more workload. They've pretty much mastered making that part of the BIOS. They just have to slightly modify their BIOSes for each motherboard that comes out and update them to deal with the newest chips.

Stop plagiarizing!

[Osty]

From the Slashdot submission:

This article discusses detailed similarities and differences involved in booting Linux on an x86-based platform (typically a PC-compatible SBC) and a custom embedded platform based around PowerPC, ARM, and others. It discusses suggested hardware and software designs and highlights the tradeoffs of each. It also describes important design pitfalls and best practices.

And from the actual article:

This installment of "Migrating from x86 to PowerPC" discusses detailed similarities and differences between booting Linux on an x86-based platform (typically a PC-compatible SBC) and a custom embedded platform based around PowerPC, ARM, and others. It discusses suggested hardware and software designs and highlights the tradeoffs of each. It also describes important design pitfalls and best practices.

Replacing the string "This installment of "Migrating from x86 to PowerPC"" with "This article" and replacing the word "between" with the phrase "involved in" is not sufficient to serve as summarization in the submitter's own words. Somehow I have a hard time believing that the submitter "Donna" and the article author Lewin Edwards are one and the same person. If I'm wrong, then fine. You can't plagiarize yourself. If I'm correct, then Slashdot's done it again. The article summary isn't an original work by Donna, but a minor modification of the article author's own summary, and should be properly attributed as such.

Re:Stop plagiarizing!

[T-Ranger]

I dont even think that you could argue that the poster implicitly tried to pass of the summary as his own work. Slashdot summaries of single articles generally dont add anything new (and frequently get it wrong). It is an abstract of the article. Since a well written introduction should itself be an abstract of the rest of the article, what makes a better abstract then a polished intro?

Re:Linux Boot

[Taladar]

You got it wrong. Not the Linux Support for ATI is bad but the ATI Support for Linux is.

Re:don't like the splash screens

[jrcamp]

If you don't want "your linux" to be "fisher-price pretty" then "go turn it the hell off in your grub menu.lst". How long does it take you to remove the splash kernel parameter? A lot less time than it does to bitch on slashdot.

I mean isn't Linux all about choice and configurability?

Re:don't like the splash screens

[m50d]

It should be friendly by default, because people who don't want it to be friendly can easily turn it off, but people who want it friendlier wouldn't know how to make it so.