Re: [gentoo-user] Dual Boot Partitions

[Florian Philipp]

Am 27.02.2011 17:02, schrieb Petri Rosenström:
> On Sun, Feb 27, 2011 at 5:01 PM, dhk <dhkuhl@×××××××××.net> wrote:
>> I have a new laptop that I need to set up for dual booting.  As much as
>> I despise Microsoft, I have to use it for certain things.  Such as some
>> obscure peripherals, like my slide photo scanner, it doesn't support
>> Linux and TD Ameritrade's streaming Java tools don't work the same as on
>> Linux.  Until corporation's smarten up Microsoft will be a problem.
>>
>> The setup for dual booting seem pretty straight forward.  Install
>> windows first, then Linux, and modify the boot loader.  However, I have
>> a couple of question and observations.
>>
>> First, the observations.  I tried to partition my disk with fdisk the
>> way I wanted.  It had the usual Linux partitions and a partition that I
>> was going to use for Window 7.  I wanted to make this an LVM2 partition,
>> but that didn't work; I guess that was too ambitious.  Then I just made
>> it an ordinary static HPFS/NTFS partition on /dev/sda5.  When installing
>> Windows 7 it wouldn't install on that partition.  I deleted all the
>> partitions and just installed it on the first 50Gigs of the disk.
>>
>> Second, the questions.  The Windows 7 install on the first 50Gigs of the
>> disk needed to created two partitions.  The first was a very small boot
>> partition that I increased to 128Megs, and the second is the rest of
>> Windows 7.  Now when I boot to the livecd to partition the rest of the
>> disk for Gentoo fdisk says "Partition 1 does not end on a cylinder
>> boundary."  Is this a problem?  The other big question is:  what do I do
> Dunno, it might be that win7 changed the amount of heads/sectors that
> could give that notice from fdisk. I would not be to worrified about
> it (Installing windows would be more horrifying). If you have a
> traditional hd then the worst thing I think might be that reads/writes
> would be slower.
>

If I'm not mistaken, this alignment is actually a good thing. It is
related to the transition from 512 B blocks to 4 kB and also helps
alignments for SSDs. In this regard, Win 7 behaves very clever and
really much better than the old and proven Linux tools (unless you know
what you are doing and are aware of every issue). IMHO it is a real
shame that most Linux tools are still behind in this regard.

If you think you have an HDD with 4kB blocks, ask and I can provide you
with some links on that topic.

>> about the first partition in the partition table?  It is an HPFS/NTFS
>> partition and has been toggled bootable.  It also has some stuff in it
>> that looks like it's important to Windows:  a BOOTSECT.BAK file, a Boot
>> directory, a System Volume Information directory, and a bootmgr file.
>> Now for my Gentoo install, how and where do I make a /boot partition?
>> Do I replace the Windows 7 boot partition with /boot?  If so, what
>> happens to the contents?  or Do I make a /boot partition on /dev/sda3
>> and toggle the bootable flag there?
>
> Something like that. You could install gentoo on one partition (I
> don't recommend).
>
> Just make partitions like you would do without windows. When you do
> the grub-install script or by hand grub links the boot to the
> partition where boot exists. You should not remove or change the
> windows partitions or the data windows will probably brake when you
> do.
>

AFAIK, grub does not need the bootable flag. Leave it alone. Maybe
Windows needs it, maybe it is just for good measure, I don't know.

Hope this helps,
Florian Philipp