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