Re: GuixSD bootable ISO-9669 image

[Danny Milosavljevic <dannym@scratchpost.org>]

Hi Ludo,

On Tue, 02 May 2017 14:37:04 +0200
ludo@gnu.org (Ludovic Courtès) wrote:

> Seems to work!

Nice :)

> Could you clarify the two “See grub” in here:
> 
> --8<---------------cut here---------------start------------->8---
> (define (iso9660-superblock-uuid sblock)
>   "Return the Volume ID of a iso9660 superblock SBLOCK as a 4-byte bytevector."
>   ;; Note: The field is the volume creation time.
>   ;; FIXME Use only certain parts (See grub).
>   ;; FIXME treat "all 0" as invalid.
>   (sub-bytevector sblock 813 17))

Yeah.  If you check out grub, /dev/disk/by-uuid or blkid, you can see that for ISO9660 filesystems, it prints the "uuids" differently (because they are not uuids, they are timestamps...).

> Should ‘iso9660-uuid->string’ be different from ‘uuid->string’?

From a purity standpoint I'd say no.  From a compatibility standpoint, yes.

> Anyway, I think we should polish and commit real soon.  :-)  Perhaps we
> can add a note about endianness and assume little endian for now.

Turns out that for the parts that we need we don't care about the endianness either way.  So I dropped the endianness now.