From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Nieuwenhuizen <janneke@gnu.org>
Subject: Re: guix system init co-existing with other distros
Date: Sun, 21 Feb 2016 23:54:22 +0100
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In-Reply-To: <87oab9sofa.fsf@gnu.org> ("Ludovic
	\=\?utf-8\?Q\?Court\=C3\=A8s\=22'\?\=
	\=\?utf-8\?Q\?s\?\= message of "Sun, 21 Feb 2016 23:12:41 +0100")
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To: Ludovic =?utf-8?Q?Court=C3=A8s?= <ludo@gnu.org>
Cc: guix-devel@gnu.org

Ludovic Court=C3=A8s writes:

> Jan Nieuwenhuizen <janneke@gnu.org> skribis:
>>    (grub-configuration
>>     (device "/dev/sda")
>>      (list (menu-entry
>>             (label "debian")
>>             (linux "(hd0,msdos3)/boot/latest")

> Did you run =E2=80=9Cguix system init config.scm /=E2=80=9D?

Fear not.  Debian lives on /dev/sda3, guix on /sda1.  From Debian
I dit guix system init config.scm /guix

> Good question!  I=E2=80=99m not sure I fully understand your hack but I=
=E2=80=99d like
> to read more about it.  :-)

So what I need is for Guix's Grub to create an extra menu entry
for Debian, with this text

    menuentry 'Debian GNU/Linux' {
	linux	/boot/vmlinuz-3.16.0-4-amd64 root=3D/dev/sda3 ro
	initrd	/boot/initrd.img-3.16.0-4-amd64
    }

When you specify extra an extra menu-entry

       (list (menu-entry
             (label "debian")
             (linux "<file-name>")
             (initrd "<file-name>))

then grub.scm:(grub-configuration-file) appends "/" "bzImage" to the
kernel's file-name

    (define linux-image-name
        (if (string-prefix? "mips" system)
            "vmlinuz"
            "bzImage"))

So, I setup some symlinks on the Debian side so that I can provide Guix's
Grub wih a kernel file name that can have "/bzImage" appended.

    23:42:13 janneke@drakenvlieg:~/src/guix
    $ ls -l /debian/boot/latest/
    totaal 0
    lrwxrwxrwx 1 root root 28  6 feb 21:17 bzImage -> /boot/vmlinuz-3.16.0-=
4-amd64
    lrwxrwxrwx 1 root root 31  6 feb 21:17 initrd -> /boot/initrd.img-3.16.=
0-4-amd64

Possibly we'd want to add another keyword

         (linux-image "(hd0,msdos3)/boot/vmlinuz-3.16.0-4-amd64")

that gets used literally?

Greetings, Jan

--=20
Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org
Freelance IT http://JoyofSource.com | Avatar=C2=AE  http://AvatarAcademy.nl=
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