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MULTIBOOTNG: SECTION II — BOOTING AND PARTIONING.

October 8, 2008

1. To run multiple OS’s you need a boot loader capable of offering a choice of which OS

to load from a menu, eg LILO or GRUB. (Smart boot is not compatible with some versions of Mandriva, Centos, and other RH derivatives. see http://www.lrz-muenchen.de/~bernhard/grub-chain-cd.html to add SBM to grub. Overwriting smart boot with another boot loader (eg GRUB) does not work! SBM leaves traces behind, which Rh objects to. The boot block must be zeroed out)

2. XP grabs the whole disk for partition C by default. If you already have XP installed, you have no

choice but to resize C; downwards. But resizers need to be used with caution.

3. Linuxes by default recognise other OS’s and install a multi-boot capable boot loader as part

of their installation process. It is customary to install XP first in a multi-boot layout, because it overwrites the existing boot loader with one that only loads linux, making the other OS’s temporarily unavailable. However, it is not too difficult to re-install a multi-boot loader.

4. If possible, partition the disk before loading any OS’s.

5. Partitioning from withing a running OS (chiefly linux) is possible but dangerous. The box should be rebooted immediately after partitioning, so that the partion table can be re-read.

6. It is preferable to partition using a Rescue of Live CD of linux. Live CD’s are better than traditional rescue CD’s , in that they include facilities like full manual pages, and a desktop calculator, handy for converting between bytes, blocks and cylinders!

7. The main linux facilities for partitioning are fdisk, sfdisk, cfdisk and partd. I prefer cfdisk for most purposes and parted for anything it doesn’t cover. Both of these are found on the Ubuntu live CD.

8. Many linuxes have installers which offer to partition the disk with fancy graphical interfaces. I have found these to be quite dubious and best avoided. Create ready-made partitions and tell the installer where to put / (root). (I prefer to install a linux all into one partition).

9. Installers will automatically detect swap partitions. Swap partitions can be created during the initial partitioning process with mkswap — it only takes a few seconds.

10. Partitioners will label a partition with a byte. This is *not* the same thing as formatting a partition, which requires mkfs. The partition type is just a label. Linux partitions have a generic label which covers various formats — ext2, ext3 and reiser. The actual formatting can be left till the install process. I usually let the installer use whichever format it defaults to. ext2 is probably the most standard. NTFS and FAT partitions should be formatted by Windows or its installer disk, although linux commands like cfisk can label them as Windows partitions, thus giving Windows a hint.

11. During the install process, linux gives you a choice between installing a boot loader to the partition ,or for the whole disk (to the MBR). If you install XP followed by a bunch of linuxes, installing boot loaders to the MBR you might up with a boot loader capable of booting all your OS’s. However, it is safer to install each boot loader searately to a partition, and a master boot loader to the MBR. (This is more likely to work, since the master boot loader only has “chain” to the local one, which is bound to be able to load its “own” linux). I use the SmartBoot loader as a master loader, which can be reconfigurd from within itself, and can recognises newly added OS’s. It cannot load linux directly, only chain, so there must be a boot loader in each partition.

A warning about GRUB: grub reads it’s configuration file “live” from a file on the linux file system (unlike LILO, which copies the information in the file into the boot record). That means that if you are using GRUB as your master loader, and that particular linux (typically the last one installed) gets corrupted — you won’t be able to boot anything! Hence my preference for an independent master boot loader.

12. During the install process, a Linux will ususally give you the opportunity of creating a boot floppy. This should definily be done, as these are extremely useful if things go wrong.

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