On 19.03.2013 10:14, Arbiel (gmx) wrote: > Hi > > Enclosed are two numbered files, generated on my own PC. > blkid.numbered, for displaying uuids > grub.cfg.numbered, generated when I installed a Ubuntu distribution on > an external device dedicated to get the internal drive of another PC > used at a place without Internet connection. > > At the other place, grub stopped running when it got at line 62, because > it did not find any 'hd1,msdos5' device, as device hd1 at installation > time had got device hd0 at running time. So the only result of this line > 62 is to have had grub fail.
The set root command only changes variable. Unless the variable is used no disk is accessed at all. > > You can see on line 12 of the blkid listing that line 64 would have > properly set root. You can also see that without lines 62 and 129, I > would have been able to start the configuration and then run > grub-mkconfig to adapt grub.cfg at the new configuration. > > So here is the reason why I asked for discontinuing the generation of > those "set root=" instructions whose only result is to have grub fail. > > As long as I am concerned, I am quite able to suppress those lines by > myself. Did you try doing so? The thing is that in that I've just done a test in VM and setting root in shell to something non-existant and then executing search works as expected > The only real issue is to consider whether or not other people > may act as I do and install a system in a place on a given configuration > and used it at another place in another configuration. > > > > Le 19/03/2013 07:50, Vladimir 'φ-coder/phcoder' Serbinenko a écrit : >> Keep list CC'ed >> On 18.03.2013 23:50, Arbiel (gmx) wrote: >> >>> Hi >>> >>> >>> Le 14/03/2013 18:59, Vladimir 'φ-coder/phcoder' Serbinenko a écrit : >>>> On 14.03.2013 16:26, Arbiel (gmx) wrote: >>>> >>>>> Hi >>>>> >>>>> The grub installation procedure should make no assumption regarding >>>>> the >>>>> eventual runtime configuration concerning device and file references. >>>>> >>>>> 1) grub.cfg file contains "set root=.." instructions which refer to >>>>> partitions which are present at installation time, but could be absent >>>>> at runtime. These instructions may cause grub to stop booting, >>>>> displaying a message "No such device", and are of no use as they are >>>>> followed by "seach --set=root ... " instructions which set root >>>>> according to the runtime configuration. >>>>> >>>>> Please, remove these "set root=.." instructions. >>>>> >>>> >>>> As long as search has found the right device, the value of root is >>>> overridden. If it didn't work the problem is somewhere else. The >>>> usefulness of these lines is for bw-compatibility mainly. >>> >>> The issue is not with the "search" instructions which, as you say, >>> overwrite the value set by the preceding "set root=(hd....)" >>> instructions. The issue is with these "set root=(hd,...) instructions >>> which can refer to an inexistant device, >> >> Not a problem since no file is referenced without explicit drive between >> these instructions >> >>> because the running >>> configuration is not what the installation configuration was. In that >>> case, grub displays a "No such device" message and stops the booting >>> procedure. >> >> If you see any such problem, it's caused by a bug somewhere else, not >> the set root statement. You write a lot about how to fix an issue you >> haven't even really shown to exist. Please provide a replication >> instructions with VM and recent bzr checkout >>>> >> >>>>> 2) grub now embeds a little file to properly set the root variable >>>>> when >>>>> core.img and grub/grub.cfg do not reside on the same partition. Such a >>>>> file should also be embedded even when both core.img and grub/grub.cfg >>>>> reside on the same partition, as the reference to this partition >>>>> may get >>>>> illegal at runtime. No one knows whether or not the destination drive >>>>> has been ported away to another configuration, where its address >>>>> differs >>>>> from what it was at installation time. >>>>> >>>> >>>> Only the partition number is stored, not the drive. And partition >>>> number >>>> doesn't change on disk move >>>> >>>>> Please always embed a file to properly set root, prefix and >>>>> config_directory. >>> >>> A recent boot-repair report showed the embedding of a 2 line grub shell >>> file to properly set the root variable to a device refered to by its >>> UUID. However, the inclusion may have been the result of the use >>> gub-mkimage command inside the installation procedure. So, the issue may >>> be to be reported to Ubiquity, the software responsible for Ubuntu >>> distributions installation. So forget about my request. >>> >> >> UUIDs are used for cross-disk installation. Partition numbers on >> single-disk ones. In any case neither changes after swapping disks >> >> >> >> >> _______________________________________________ >> Bug-grub mailing list >> Bug-grub@gnu.org >> https://lists.gnu.org/mailman/listinfo/bug-grub >>
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