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On Oct 5, 2011 8:59 PM, "Grant Edwards" <grant.b.edwards@×××××.com> wrote: |
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> |
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> On 2011-10-04, Canek Pel??ez Vald??s <caneko@×××××.com> wrote: |
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> > On Tue, Oct 4, 2011 at 3:14 PM, Grant Edwards <grant.b.edwards@×××××.com> |
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wrote: |
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> >> On 2011-10-04, Canek Pel??ez Vald??s <caneko@×××××.com> wrote: |
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> >>> On Tue, Oct 4, 2011 at 2:24 PM, Grant Edwards < |
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grant.b.edwards@×××××.com> wrote: |
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> >>>> On 2011-10-04, Canek Pel??ez Vald??s <caneko@×××××.com> wrote: |
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> >>>> |
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> >>>>> Then any boot loader will need to call something to start it. |
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> >>>>> Understand this: any Linux/Unix init system (systemd, SysV, Upstart, |
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> >>>>> OpenRC) is simply a program... that the Linux kernel itself |
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executes. |
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> >>>> |
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> >>>> I know. ??What I don't understand is the statement that grub2 calls |
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(or |
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> >>>> connects to) the init system. |
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> >>>> |
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> >>>>> That's the init= command line in the kernel. |
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> >>>>> |
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> >>>>> The bootloader calls an operating system. The init system (if at |
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all) |
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> >>>>> that the OS uses doesn't matter: so if you have an operating system, |
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> >>>>> any bootloader should be able to boot it (bearing things like being |
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> >>>>> able to understand the filesystem etc.) |
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> >>>> |
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> >>>> I know how bootloaders like LILO and grub-legacy work. ??What I don't |
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> >>>> understand is the statement that grub2 is somehow aware of the booted |
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> >>>> OS's init system. |
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> >>> |
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> >>> Oh. The configuration file of GRUB2 is autogenerated, and this means |
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> >>> that the init=systemd has to be passed to the kernel line. |
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> >>> |
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> >>> In that sense, GRUB2 is "aware" of it. |
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> >> |
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> >> So to use grub2 you have to replace the normal "init" program that's |
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> >> started by the kernle as PID#1 with something else? |
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> > |
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> > No. |
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> |
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> I give up. I've absolutely no idea what grub2 has to do with the OS's |
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> init system, and none of what you've written makes any sense to me. |
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I think what he meant was: |
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The *installer* portion of grub2 is aware of which pid#0 is running when it |
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auto-creates the bootloader's configuration. That pid#0 is passed on to the |
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kernel by the bootloader. |
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The *bootloader* portion of grub2 don't know and don't care what is being |
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used as pid#0 by the OS. All it knows is that the installer portion has |
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specified something to be passed to the OS. And that's what it does, without |
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understanding anything about pid#0. |
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rgds, |
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