On Mon, Jul 2, 2012 at 5:26 PM, mike cloaked <mike.cloaked@xxxxxxxxx> wrote: > I have been following the discussions in various places including on > this list about the forthcoming change from grub to become grub-legacy > and the default bootloader becoming grub2. > > On all my arch systems I have grub with MBR partitioning, booting to > BIOS initially - and none of my systems is modern enough to have UEFI > instead of BIOS. > > So I have been reading up on what I will need to do when grub2 version > 2.00 appears in [core] - and how to successfully achieve the > changeover. However I still cannot determine if it will be "necessary" > to make sure that there is a post-MBR gap of 2MiB between the MBR and > the first partition when the system will remain using MBR partitioning > and grub2 will be the bootloader. So this applies to systems with no > GPT partitions, and no UEFI. > > In my systems that have been running some time some have 64 sectors to > where the start of the first partition is, and others have 2,000 > sectors which is about 1MiB - and I still don't know if grub2 version > 2.00 will not work on those systems or not. I do know that other > distros such as Fedora version F16 have systems running successfully > using grub2 prior to version 2.00 with MBR partitioning and BIOS and > boot perfectly well without the 2MiB post MBR gap. Perhaps this > changes with the release of grub2 version 2.00? > > Achieving a post-MBR gap of at least 2MiB will be a painful process as > shrinking the first partition and then moving it towards partition 2 > with an MBR partitioned disk is time consuming and not always > successful in those systems where in the past I have adjusted the > partitions on a drive. Maybe the recent versions of tools such as > PartedMagic will cope better than it did a couple of years ago? > > Can someone help out with a clear explanation please. I am usually > pretty good with upgrades and preparation but this has foxed me! i.e. > specifically for a BIOS-MBR hard drive using grub2 that it is vital to > have a post-MBR gap of at least 2 MiB (where no GPT partitioning will > be in use)? > > Thanks The best I could guess at for the way an upgrade with my systems would work - is that if I have a disk with a 64 sector post-MBR gap (where 1 sector is 512 bytes), is that grub2 with BIOS-MBR and a /boot partition, would still work but that it might be more efficient putting it on a disc where the post-MBR gap is 2MiB - but changing to the larger post-MBR gap is not an "essential" change prior to changing from grub to grub2 - though I would like someone more expert than me to tell me if I am right or wrong! Thanks -- mike c
