bootloader API and dual boot

bootloader API and dual boot

[Thomas Danckaert]

Hi Guix,

I had to update my system configuration, which contains a boot menu entry for another distribution, to use the new bootloader API, but the manual section on dual boot configuration (https://www.gnu.org/software/guix/manual/guix.html#index-dual-boot) was not updated for this new API.  I would send a patch myself, but I'm afraid I don't really understand the “boot-parameters” record well enough (e.g. things like “root-device” vs “store-device” confuse me, and I don't know what "boot-name" means).  Can you help me?

Currently, the manual states that extra menu entries can be added as a list of <menu-entry> records like the following:

(menu-entry
  (label "The Other Distro")
  (linux "/boot/old/vmlinux-2.6.32")
  (linux-arguments '("root=/dev/sda2"))
  (initrd "/boot/old/initrd"))

but menu-entry is specific to grub (and no longer exported from the grub module).  I got it to work using a list of <boot-parameters> instead, like the following:

 (boot-parameters
  (label "The Other Distro")
  (kernel "/boot/old/vmlinux-2.6.32")
  (kernel-arguments '("root=/dev/sda2"))
  (initrd "/boot/old/initrd")
  (store-device (uuid "xyz"))
  (store-mount-point "/")
  (boot-name #f) ; unnecessary?
  (root-device (uuid "xyz")) ; unnecessary?
)

So I suppose the manual should be changed to reflect this.

I have the impression that “boot-name”, “store-mount-point” and “root-device” are not used for a dual boot config record, but I had to add them to get guix system to accept my configuration (because there are no default entries for these fields?).  Also, the names “store-device” and “store-mount-point” are a bit confusing for a non-GuixSD distribution (which doesn't necessarily have a store) (or I completely misunderstand them :-) ).  Am I right that some of those fields are redundant for dual boot configurations?  Can we add default values for some of <boot-parameters>'s fields?

Thanks!

Thomas