Re: [gentoo-user] Dual Boot Partitions

[dhk <dhkuhl@optonline.net>]

On 02/27/2011 02:39 PM, Mick wrote:
> On Sunday 27 February 2011 18:04:26 Florian Philipp wrote:
>> Am 27.02.2011 17:02, schrieb Petri Rosenström:
>>> On Sun, Feb 27, 2011 at 5:01 PM, dhk <dhkuhl@optonline.net> wrote:
> 
>>>> First, the observations.  I tried to partition my disk with fdisk the
>>>> way I wanted.  
> 
> I would recommend you use 'parted -a optimal' or gparted for this purpose (see 
> below).
> 
> 
>>>> 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.
> 
> I am not sure that you can use LVM2 for MSWindows - as far as I know they use 
> Logical Disk Manager which it is not the same with any other sane LVM 
> implementation - come on now, would you expect them to seek compatibility or 
> interoperability?!!
> 
> http://en.wikipedia.org/wiki/Logical_Disk_Manager
> 
>>>> 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.
> 
> Only some are.
> 
> The 'parted -a optimal' or gparted will seek to align the end of a partition, 
> but you will find that it may under/overshoot your specified size to achieve 
> that.
> 
> fdisk et al have some development to do yet.
> 
> 
>> 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).
> 
> No!  Nothing like that.  Leave the MS Windows boot partition alone and flagged 
> as boot.  MS Windows needs this, while Linux does not.
> 
> 
>>> 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.
> 
> Yep.  Create a new partition; e.g. /dev/sda3 and use that as the /boot 
> mountpoint for your Linux OS.  This is where the grub fs, Linux OS kernels and 
> related files will be saved.
> 
> 
>> 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.
> 
> This is correct, MS Windows needs it and it will not boot without it, 
> especially if you retain the MSWindows MBR boot code - although you can 
> install GRUB in the MBR and chainload MSWindows from there with it.
> 
> HTH.

Thanks for all the input.  It helped clear up a lot of questions.  I
spent the weekend installing to Operating Systems and it looks like it
almost worked.  I think the problem is in the Grub setup, so it should
be repairable once I find the mistake.  If it's something else, I may be
doing this again next weekend.

Thanks again,

dhk