On Wed, May 29, 2013, at 04:25 AM, Andrea Conti wrote: > >> We can't have more then 4 primary partitions on a hard disk. > >> > >> Gentoo needs 2 partitions, /boot and a Virtual partition (that count's > >> as well as one primary) with all the other folders. > >> > >> Windows will create 2. and Mac OSX minimum 1, am I right?! > >> > > > > Your Windows partitions have to be in the first four, but OSX and linux > > partitions can be anywhere thanks to the gpt partition table. > > Things are both simpler and more complex than that. > > The real problem is that while rEFIt/rEFInd, OSX and Linux have no > problem dealing with a GPT partition table, Windows only supports MBR. > (Windows 7+ supports GPT partition tables but it can only boot from a > GPT disk in EFI mode. On a Mac OSes other than OSX must be booted in > BIOS emulation mode, therefore the requirement for MBR on the system > disk for Windows still stands). > > GPT and MBR, however, are only indexing schemes: they describe how many > partitions are on a disk and their location, but apart from providing a > high level 'type' label they have nothing to do with what's inside a > partition. > > GPT-partitioned disks traditionallly have what's called a 'protective > MBR', i.e. a dummy MBR which defines a single partition of type 0xEE > spanning the whole disk; this is intended to keep partitioning tools > that are not GPT-aware from considering the disk uninitialized and > inadvertently destroying its contents. > However, nothing prevents you from adding to the protective MBR regular > entries for some of the partitions, and have the disk look like a > 'normal' MBR disk as far as those partitions are concerned. > > The result is called a 'hybrid MBR' and it's the main trick behind Boot > Camp. There is really nothing special about booting (or installing) > Windows on a Mac: it just works, as long as you have both a properly set > up hybrid MBR with an entry for the Windows partition and a suitable EFI > boot manager. > > The former can be done with a tool such as gpt-fdisk (you can easily > find a binary package for OSX, and there are directions for dealing with > hybrid MBRs on the author's site); rEFInd is your best option for the > latter. The standard Apple boot manager will also do, if you only need > to boot OSX and Windows. > > Booting Linux works in a similar fashion. You don't even need a > GPT-aware bootloader: good old GRUB 1 is perfectly up to the task, as > long as there is an entry for its boot partition in the hybrid MBR. Then > you can load a kernel with GPT support, and from there it's just a > standard multiboot setup. > > HTH, > andrea
Thanks Andrea. I had though that the MBR was automatically mapped to the the first 4 gpt partitions because that's they way it's always been on my system. So now I wonder how it's been set that way, because I know i've never touched gpt-fdisk and I didn't use bootcamp. Maybe the refit installer.
