Re: [gentoo-user] Re: Gentoo on a Dell XPS 13 Ultrabook

[Alan McKinnon]

On Sun, 4 Mar 2012 13:56:23 -0800
Grant <emailgrant@×××××.com> wrote:

> >> [snip]
> >>>> 1. fdisk won't let me specify a start block before 2048 even
> >>>> though I deleted all partitions.
> >>>>
> >>>
> >>> That's normal. It's a long story, but Windows Vista and Windows 7
> >>> expects the first partition to start at sector 2048.
> >>>
> >>> You can force a lower number by toggling "DOS compatibility";
> >>> this should let you start the first partition as low as sector 63.
> >>>
> >>> HOWEVER, make sure that all partitions begin at multiples of 8
> >>> (e.g., 64, 72, 80, and so on); this will save you a lot of grief
> >>> if it happens that the hard disk you're using has 4KiB-sectors.
> >>
> >> I just looked up the start block for my other systems and they're
> >> all on 63.  Is performance impacted on all of these systems since
> >> they aren't started on 64?
> >>
> >> - Grant
> >>
> >
> > The performance is only impacted if the sector size is something
> > other than 512 bytes. The newer 4K sector size used by some higher
> > density drives requires that you start partitions on a sector
> > boundary or they will perform badly. There isn't an actually
> > performance need to actually start on 2048 but the fdisk-type
> > developer folks are doing that to be more compatible with newer
> > Windows installations.
>
> All my drives says this from fdisk:
>
> Units = sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
>
> So it doesn't matter where the first partition starts?

Correct. Those drives are all the same style as you've 
been using for years. If partitions start at 63, that's just an msdos
convention. For reasons I've never understood, Windows liked to reserve
the first 32k for some purpose or other.


-- 
Alan McKinnnon
alan.mckinnon@×××××.com