On Wed, Oct 5, 2011 at 6:55 AM, 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.
Others explain it too. The GRUB2 bootloader has nothing to do with the init system, except for passing thi init= command line, and it is not required that it does. The GRUB2 userspace, used to generate the config file, can be made aware of what init system is to be used, making the bootloader to pass the init= command line to the kernel. That is all. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
