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

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

[Grant]

I just received the new Dell XPS 13 Ultrabook and I'm trying to
install Gentoo but I can't get install-amd64-minimal-20120223.iso to
boot via a USB key.  I installed it to two different USB keys via
unetbootin but I get this right after it asks for the keymap:

Looking for the cdrom
Attempting to mount media:- /dev/sda1
Attempting to mount media:- /dev/sda2
Attempting to mount media:- /dev/sda3
Attempting to mount media - /dev/sda4
Media not found
No bootable medium found. Waiting for new devices...
Could not find CD to boot, something else needed!
Determining root device...
Could not find the root block device in .

It must be reading the USB key fine or it never would have gotten that
far.  Maybe it has no drivers for the disk controller, but then why
does it reference the cdrom?  I tried the nosata and ide=nodma options
to no avail.

- Grant

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

[Alan McKinnon]

On Thu, 1 Mar 2012 18:12:11 -0800
Grant <emailgrant@gmail.com> wrote:

> I just received the new Dell XPS 13 Ultrabook and I'm trying to
> install Gentoo but I can't get install-amd64-minimal-20120223.iso to
> boot via a USB key.  I installed it to two different USB keys via
> unetbootin but I get this right after it asks for the keymap:
> 
> Looking for the cdrom
> Attempting to mount media:- /dev/sda1
> Attempting to mount media:- /dev/sda2
> Attempting to mount media:- /dev/sda3
> Attempting to mount media - /dev/sda4
> Media not found
> No bootable medium found. Waiting for new devices...
> Could not find CD to boot, something else needed!
> Determining root device...
> Could not find the root block device in .
> 
> It must be reading the USB key fine or it never would have gotten that
> far.  Maybe it has no drivers for the disk controller, but then why
> does it reference the cdrom?  I tried the nosata and ide=nodma options
> to no avail.

Use some other distro on the USB device to get you a chroot.

Check BIOS carefully. Some of those options can dick with booting
immensely

-- 
Alan McKinnnon
alan.mckinnon@gmail.com

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

[Grant]

>> I just received the new Dell XPS 13 Ultrabook and I'm trying to
>> install Gentoo but I can't get install-amd64-minimal-20120223.iso to
>> boot via a USB key.  I installed it to two different USB keys via
>> unetbootin but I get this right after it asks for the keymap:
>>
>> Looking for the cdrom
>> Attempting to mount media:- /dev/sda1
>> Attempting to mount media:- /dev/sda2
>> Attempting to mount media:- /dev/sda3
>> Attempting to mount media - /dev/sda4
>> Media not found
>> No bootable medium found. Waiting for new devices...
>> Could not find CD to boot, something else needed!
>> Determining root device...
>> Could not find the root block device in .
>>
>> It must be reading the USB key fine or it never would have gotten that
>> far.  Maybe it has no drivers for the disk controller, but then why
>> does it reference the cdrom?  I tried the nosata and ide=nodma options
>> to no avail.
>
> Use some other distro on the USB device to get you a chroot.

Thanks Alan, I'm installing via a Kubuntu ISO.  Does Gentoo have
anything like a daily live ISO?

- Grant

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

[Neil Bothwick]

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On Fri, 2 Mar 2012 12:29:51 -0800, Grant wrote:

> Does Gentoo have anything like a daily live ISO?

Closer to weekly, but look in releases/autobuilds on your favourite
mirror.


-- 
Neil Bothwick

Experience is what you get when you didn't get what you wanted.


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

[walt]

On 03/01/2012 06:12 PM, Grant wrote:
> I just received the new Dell XPS 13 Ultrabook and I'm trying to
> install Gentoo but I can't get install-amd64-minimal-20120223.iso to
> boot via a USB key.

Have you tested your boot USB keys on another machine?

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

[Grant]

>> Does Gentoo have anything like a daily live ISO?
>
> Closer to weekly, but look in releases/autobuilds on your favourite
> mirror.

Got it, thanks.

- Grant

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

[Grant]

>> I just received the new Dell XPS 13 Ultrabook and I'm trying to
>> install Gentoo but I can't get install-amd64-minimal-20120223.iso to
>> boot via a USB key.
>
> Have you tested your boot USB keys on another machine?

Gentoo is installed but I can't get my USB->ethernet adapter to bring
up an eth0 (or any other) interface.  It works if I boot the Kubuntu
USB key.  I've definitely built the correct driver into the kernel
(mcs7380).  I'm going through an emerge world right now to bring
everything up to date.  Is there anything else I might need to do?

- Grant

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

[Grant]

>>> I just received the new Dell XPS 13 Ultrabook and I'm trying to
>>> install Gentoo but I can't get install-amd64-minimal-20120223.iso to
>>> boot via a USB key.
>>
>> Have you tested your boot USB keys on another machine?
>
> Gentoo is installed but I can't get my USB->ethernet adapter to bring
> up an eth0 (or any other) interface.  It works if I boot the Kubuntu
> USB key.  I've definitely built the correct driver into the kernel
> (mcs7380).  I'm going through an emerge world right now to bring
> everything up to date.  Is there anything else I might need to do?
>
> - Grant

I enabled some more kernel options under USB Network Adapters and it's
working now.  The install is about done but there were a few
peculiarities:

1. fdisk won't let me specify a start block before 2048 even though I
deleted all partitions.

2. grub-install reported something like:

fd0
hd0
hd1

where hd1 was the USB key.  Should I fix this to remove the USB key from grub?

3. Portage complains about duplicate repositories.  I think it has to
do with the fact that I ran emerge --sync without downloading and
extracting an initial snapshot.

Please let me know if you have any idea on these.

- Grant

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

[Pandu Poluan]

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On Mar 4, 2012 12:54 AM, "Grant" <emailgrant@gmail.com> wrote:
>
> >>> I just received the new Dell XPS 13 Ultrabook and I'm trying to
> >>> install Gentoo but I can't get install-amd64-minimal-20120223.iso to
> >>> boot via a USB key.
> >>
> >> Have you tested your boot USB keys on another machine?
> >
> > Gentoo is installed but I can't get my USB->ethernet adapter to bring
> > up an eth0 (or any other) interface.  It works if I boot the Kubuntu
> > USB key.  I've definitely built the correct driver into the kernel
> > (mcs7380).  I'm going through an emerge world right now to bring
> > everything up to date.  Is there anything else I might need to do?
> >
> > - Grant
>
> I enabled some more kernel options under USB Network Adapters and it's
> working now.  The install is about done but there were a few
> peculiarities:
>
> 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. [1]

> 2. grub-install reported something like:
>
> fd0
> hd0
> hd1
>
> where hd1 was the USB key.  Should I fix this to remove the USB key from
grub?
>

I see no problem. The lower number is still the internal hard disk, so grub
shouldn't have any trouble booting.

> 3. Portage complains about duplicate repositories.  I think it has to
> do with the fact that I ran emerge --sync without downloading and
> extracting an initial snapshot.
>

Try 'rm -rf /usr/portage', download (or copy) portage-latest tarball, and
extract it into a re-created /usr/portage

> Please let me know if you have any idea on these.
>
> - Grant
>

Rgds,

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

[Pandu Poluan]

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On Mar 4, 2012 1:13 AM, "Pandu Poluan" <pandu@poluan.info> wrote:
>
>
> On Mar 4, 2012 12:54 AM, "Grant" <emailgrant@gmail.com> wrote:
> >

> >
> > I enabled some more kernel options under USB Network Adapters and it's
> > working now.  The install is about done but there were a few
> > peculiarities:
> >
> > 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. [1]
>

[1] http://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/

Rgds,

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

[Pandu Poluan]

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Oh iya, satu lagi yang perlu dihindari: wifi AP nya HP ProCurve / HP
Networking. Nggak stabil. (Tapi kalau switch Layer 2 dan Layer 3 nya, HP
ProCurve highly recommended).

((Ini berdasarkan hasil pengalaman saya di kantor yang sekarang.))

Rgds,
 On Mar 4, 2012 1:15 AM, "Pandu Poluan" <pandu@poluan.info> wrote:

>
> On Mar 4, 2012 1:13 AM, "Pandu Poluan" <pandu@poluan.info> wrote:
> >
> >
> > On Mar 4, 2012 12:54 AM, "Grant" <emailgrant@gmail.com> wrote:
> > >
>
> > >
> > > I enabled some more kernel options under USB Network Adapters and it's
> > > working now.  The install is about done but there were a few
> > > peculiarities:
> > >
> > > 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. [1]
> >
>
> [1] http://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/
>
> Rgds,
>

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

[Pandu Poluan]

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Gah. I must be too tired; what I sent earlier was supposed to go another
list. Sorry for the mistake, folks.

Rgds,
 On Mar 4, 2012 1:22 AM, "Pandu Poluan" <pandu@poluan.info> wrote:

> Oh iya, satu lagi yang perlu dihindari: wifi AP nya HP ProCurve / HP
> Networking. Nggak stabil. (Tapi kalau switch Layer 2 dan Layer 3 nya, HP
> ProCurve highly recommended).
>
> ((Ini berdasarkan hasil pengalaman saya di kantor yang sekarang.))
>
> Rgds,
>  On Mar 4, 2012 1:15 AM, "Pandu Poluan" <pandu@poluan.info> wrote:
>
>>
>> On Mar 4, 2012 1:13 AM, "Pandu Poluan" <pandu@poluan.info> wrote:
>> >
>> >
>> > On Mar 4, 2012 12:54 AM, "Grant" <emailgrant@gmail.com> wrote:
>> > >
>>
>> > >
>> > > I enabled some more kernel options under USB Network Adapters and it's
>> > > working now.  The install is about done but there were a few
>> > > peculiarities:
>> > >
>> > > 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. [1]
>> >
>>
>> [1] http://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/
>>
>> Rgds,
>>
>

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

[Joshua Murphy]

On Sat, Mar 3, 2012 at 1:13 PM, Pandu Poluan <pandu@poluan.info> wrote:
>
> On Mar 4, 2012 12:54 AM, "Grant" <emailgrant@gmail.com> wrote:
>>
>> >>> I just received the new Dell XPS 13 Ultrabook and I'm trying to
>> >>> install Gentoo but I can't get install-amd64-minimal-20120223.iso to
>> >>> boot via a USB key.
>> >>
>> >> Have you tested your boot USB keys on another machine?
>> >
>> > Gentoo is installed but I can't get my USB->ethernet adapter to bring
>> > up an eth0 (or any other) interface.  It works if I boot the Kubuntu
>> > USB key.  I've definitely built the correct driver into the kernel
>> > (mcs7380).  I'm going through an emerge world right now to bring
>> > everything up to date.  Is there anything else I might need to do?
>> >
>> > - Grant
>>
>> I enabled some more kernel options under USB Network Adapters and it's
>> working now.  The install is about done but there were a few
>> peculiarities:
>>
>> 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. [1]

<snip the rest>

From what I recall of looking at that toy's specs, it's running on an
SSD, so it becomes even more important, performance-wise, to have
things aligned properly so any one write doesn't cause two full erase
blocks to be cycled. The 1MB alignment is, if I recall, a balance
Microsoft struck as the midpoint between multiple hardware vendors to
work well on any of them... raid arrays, SSDs, advanced format hard
drives with 4k sectors on-disk, etc.

-- 
Poison [BLX]
Joshua M. Murphy

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

[Grant]

[snip]
>> I enabled some more kernel options under USB Network Adapters and it's
>> working now.  The install is about done but there were a few
>> peculiarities:
>>
>> 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. [1]

Got it, I'll just stick with 2048.

>> 2. grub-install reported something like:
>>
>> fd0
>> hd0
>> hd1
>>
>> where hd1 was the USB key.  Should I fix this to remove the USB key from
>> grub?
>>
>
> I see no problem. The lower number is still the internal hard disk, so grub
> shouldn't have any trouble booting.

Sounds good.

>> 3. Portage complains about duplicate repositories.  I think it has to
>> do with the fact that I ran emerge --sync without downloading and
>> extracting an initial snapshot.
>>
>
> Try 'rm -rf /usr/portage', download (or copy) portage-latest tarball, and
> extract it into a re-created /usr/portage

I tried that but I get the same message:

"WARNING: One of more repositories have been ignored due to duplicate
profiles/repo_name entires:

/, gentoo, /usr/local/portage overrides
/usr/portage

All profiles/repo_name entries must be unique in order to avoid having
duplicates ignored.  Set PORTAGE_REPO_DUPLICATE_WARN="0" in
/etc/make.conf if you would like to disable this warning."

- Grant

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

[Grant]

> [snip]
>>> I enabled some more kernel options under USB Network Adapters and it's
>>> working now.  The install is about done but there were a few
>>> peculiarities:
>>>
>>> 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. [1]
>
> Got it, I'll just stick with 2048.
>
>>> 2. grub-install reported something like:
>>>
>>> fd0
>>> hd0
>>> hd1
>>>
>>> where hd1 was the USB key.  Should I fix this to remove the USB key from
>>> grub?
>>>
>>
>> I see no problem. The lower number is still the internal hard disk, so grub
>> shouldn't have any trouble booting.
>
> Sounds good.
>
>>> 3. Portage complains about duplicate repositories.  I think it has to
>>> do with the fact that I ran emerge --sync without downloading and
>>> extracting an initial snapshot.
>>>
>>
>> Try 'rm -rf /usr/portage', download (or copy) portage-latest tarball, and
>> extract it into a re-created /usr/portage
>
> I tried that but I get the same message:
>
> "WARNING: One of more repositories have been ignored due to duplicate
> profiles/repo_name entires:
>
> /, gentoo, /usr/local/portage overrides
> /usr/portage
>
> All profiles/repo_name entries must be unique in order to avoid having
> duplicates ignored.  Set PORTAGE_REPO_DUPLICATE_WARN="0" in
> /etc/make.conf if you would like to disable this warning."
>
> - Grant

Just figured it out.  I had a duplicate tree in /usr/local/portage
which I just deleted.  I had to re-set my profile with eselect.
Please let me know if there's anything else I might have to re-do.

- Grant

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

[Grant]

[snip]
>> 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. [1]
>
> <snip the rest>
>
> From what I recall of looking at that toy's specs, it's running on an
> SSD, so it becomes even more important, performance-wise, to have
> things aligned properly so any one write doesn't cause two full erase
> blocks to be cycled. The 1MB alignment is, if I recall, a balance
> Microsoft struck as the midpoint between multiple hardware vendors to
> work well on any of them... raid arrays, SSDs, advanced format hard
> drives with 4k sectors on-disk, etc.

Just to confirm, starting at block 2048 is OK?

- Grant

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

[Alex Schuster]

Grant writes:

> Just to confirm, starting at block 2048 is OK?

Yes, if it's divisible by 8, it's okay. That's because 512 * 8 = 4096, so
every 8th 512-byte block starts on a 4096 block boundary.

Now I have a related question: My new seagate Barracuda
Green 2TB ST2000DL003-9VT166 drive has 4096 bytes per sector, but uses
something that is called SmartAlign(TM) [*]. Seagate says that there are
no performance impacts even when the partitions are misaligned. This
would be good, because I completely forgot about this when creating
partitions, and I would like to keep it as it is now. Has anyone heard
about this? Can I trust Seagate that what they say is correct?

[*] www.seagate.com/docs/pdf/de.../mb6101_smartalign_technology_faq.pdf 

	Wonko

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

[Grant]

[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

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

[Mark Knecht]

On Sun, Mar 4, 2012 at 1:09 PM, Grant <emailgrant@gmail.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.

HTH,
Mark

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

[Grant]

>> [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?

- Grant

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

[Alan McKinnon]

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

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

[Grant]

>> >> [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.

So fdisk used to enforce a block 63 start point and now it enforces a
2048 start point?  fdisk is the one doing this?

- Grant

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

[Pandu Poluan]

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On Mar 5, 2012 3:37 AM, "Alex Schuster" <wonko@wonkology.org> wrote:
>
> Grant writes:
>
> > Just to confirm, starting at block 2048 is OK?
>
> Yes, if it's divisible by 8, it's okay. That's because 512 * 8 = 4096, so
> every 8th 512-byte block starts on a 4096 block boundary.
>
> Now I have a related question: My new seagate Barracuda
> Green 2TB ST2000DL003-9VT166 drive has 4096 bytes per sector, but uses
> something that is called SmartAlign(TM) [*]. Seagate says that there are
> no performance impacts even when the partitions are misaligned. This
> would be good, because I completely forgot about this when creating
> partitions, and I would like to keep it as it is now. Has anyone heard
> about this? Can I trust Seagate that what they say is correct?
>
> [*] www.seagate.com/docs/pdf/de.../mb6101_smartalign_technology_faq.pdf
>
>        Wonko
>

Your URL got munged there, I can't download the pdf.

Rgds,

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

[Pandu Poluan]

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On Mar 5, 2012 3:15 AM, "Grant" <emailgrant@gmail.com> wrote:
>
> [snip]
> >> 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. [1]
> >
> > <snip the rest>
> >
> > From what I recall of looking at that toy's specs, it's running on an
> > SSD, so it becomes even more important, performance-wise, to have
> > things aligned properly so any one write doesn't cause two full erase
> > blocks to be cycled. The 1MB alignment is, if I recall, a balance
> > Microsoft struck as the midpoint between multiple hardware vendors to
> > work well on any of them... raid arrays, SSDs, advanced format hard
> > drives with 4k sectors on-disk, etc.
>
> Just to confirm, starting at block 2048 is OK?
>

No problem. You'll just be shortchanged of almost 1MiB. Nothing to lose
sleep over, IMO.

The most important thing is to make sure that *all* partitions begin on
sectors divisible by 8. So, if you're going to set up multiple partitions,
eyeball their start sectors carefully.

Rgds,

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

[Pandu Poluan]

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On Mar 5, 2012 4:59 AM, "Grant" <emailgrant@gmail.com> wrote:
>
>
> 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?
>

Older BIOSes don't understand that hard disks now can have 4KiB sectors, so
some of the "advanced format" hard disks report a sector size of 512B. But
behind the scenes, the hard disk maps the logical sector to a subsector of
the physical sector.

The only sure fire way to find out if your hard disk uses 4KiB sectors is
to open your computer and eyeball the hard disk. All 4KiB hard disks that I
know of have statements on their surface that tell me so.

Rgds,

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

[Pandu Poluan]

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On Mar 5, 2012 5:10 AM, "Alan McKinnon" <alan.mckinnon@gmail.com> wrote:
>
>
> 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.
>

Partitions start at sector 63 because traditionally that's the first sector
of the second cylinder. If the partition starts at a lower sector, then the
metadata of the filesystem might get split between two cylinders, causing a
performance impact due to drive head repositioning (older -- like, *really
old* drives -- have slow and inaccurate actuators; repositioning heads
takes time because after moving the heads, the location needs some fine
tuning by reading some calibration data embedded in every cylinder).

Rgds,

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

[Pandu Poluan]

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On Mar 5, 2012 5:39 AM, "Grant" <emailgrant@gmail.com> wrote:
>
>
> So fdisk used to enforce a block 63 start point and now it enforces a
> 2048 start point?  fdisk is the one doing this?
>
> - Grant
>

Yes. Like I posted before (and explained in the article I linked), if you
turn off the compatibility mode, you can push it down to 63.

Not recommended, though. Not only will you lose compatibility with Windows,
but also you'll only gain slightly less than 1MiB. And who knows in the
future something absofuckinlutely requires the first partition to begin at
sector 2048.

So, IMO, disabling the DOS compatibility gives one too small a gain that's
worth the (possible) headache in the future.

Rgds,

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

[Alex Schuster]

Pandu Poluan writes:

> On Mar 5, 2012 3:37 AM, "Alex Schuster" <wonko@wonkology.org> wrote:

> > Now I have a related question: My new seagate Barracuda
> > Green 2TB ST2000DL003-9VT166 drive has 4096 bytes per sector, but uses
> > something that is called SmartAlign(TM) [*]. Seagate says that there
> > are no performance impacts even when the partitions are misaligned.
> > This would be good, because I completely forgot about this when
> > creating partitions, and I would like to keep it as it is now. Has
> > anyone heard about this? Can I trust Seagate that what they say is
> > correct?
> >
> > [*]
> > www.seagate.com/docs/pdf/de.../mb6101_smartalign_technology_faq.pdf

> Your URL got munged there, I can't download the pdf.

Argh, how did that happen? I just copied from Firefox' address bar. And it
was in German anyway. Sorry. But somehow interesting, seems I sometimes
don't even notice which language a text is written in.

Here is the English version:
http://www.seagate.com/docs/pdf/whitepaper/tp615_smartalign_for_af_4k.pdf

This link also has some information, and the other one explains what the
problem with a 4K sector size is. But beware, this may well be Seagate
propaganda.

http://consumer.media.seagate.com/2010/06/the-digital-den/advanced-format-drives-with-smartalign/
http://consumer.media.seagate.com/2010/03/the-digital-den/4k-sector-hard-drive-primer/

	Wonko

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

[Alex Schuster]

Grant writes:

> > 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

Neither fdisk nor hdparm seem to get the correct sector size, at least
not always. That's what I read somewhere (and not only once), and it's
true for my own 2TB drive which I know to have a 4K sector size. I'd say
you have to look up the specs on the vendor's web size to be sure.

> So it doesn't matter where the first partition starts?

If you have 4K sectors (and not a Seagate drive with SmartAlign [*]), it
does.

BTW, here's some benchmarks I just stumbled upon:
http://hothardware.com/Articles/WDs-1TB-Caviar-Green-w-Advanced-Format-Windows-XP-Users-Pay-Attention/?page=2

[*] I don't want to sound like I'm advertising for Seagate here, but at
least it seems that with SmartAlign the performance impact will be
much less, so it might not be worth the trouble of re-partitioning drives
that are already being used.

	Wonko

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

[Pandu Poluan]

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On Mar 5, 2012 11:04 PM, "Alex Schuster" <wonko@wonkology.org> wrote:
>
> Grant writes:
>
> > > 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
>
> Neither fdisk nor hdparm seem to get the correct sector size, at least
> not always. That's what I read somewhere (and not only once), and it's
> true for my own 2TB drive which I know to have a 4K sector size. I'd say
> you have to look up the specs on the vendor's web size to be sure.
>
> > So it doesn't matter where the first partition starts?
>
> If you have 4K sectors (and not a Seagate drive with SmartAlign [*]), it
> does.
>
> BTW, here's some benchmarks I just stumbled upon:
>
http://hothardware.com/Articles/WDs-1TB-Caviar-Green-w-Advanced-Format-Windows-XP-Users-Pay-Attention/?page=2
>
> [*] I don't want to sound like I'm advertising for Seagate here, but at
> least it seems that with SmartAlign the performance impact will be
> much less, so it might not be worth the trouble of re-partitioning drives
> that are already being used.
>
>        Wonko
>

The problem with SmartAlign is that..*.* it's magic... once you run out of
mana, you can kiss your data goodbye.

In other words, I tried to find how it works, but Seagate seems to be mum;
and that is ungood. Without knowing how exactly the technology works, how
can we be sure that it won't blow up when encountering edge/corner cases?

So, albeit nice (in the sense that one does not have to experience the
headache in ensuring that partitions are properly aligned), I personally
will stay away from magical things.

Rgds,

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

[Alan McKinnon]

On Mon, 5 Mar 2012 23:33:20 +0700
Pandu Poluan <pandu@poluan.info> wrote:

> On Mar 5, 2012 11:04 PM, "Alex Schuster" <wonko@wonkology.org> wrote:
> >
> > Grant writes:
> >
> > > > 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
> >
> > Neither fdisk nor hdparm seem to get the correct sector size, at
> > least not always. That's what I read somewhere (and not only once),
> > and it's true for my own 2TB drive which I know to have a 4K sector
> > size. I'd say you have to look up the specs on the vendor's web
> > size to be sure.
> >
> > > So it doesn't matter where the first partition starts?
> >
> > If you have 4K sectors (and not a Seagate drive with SmartAlign
> > [*]), it does.
> >
> > BTW, here's some benchmarks I just stumbled upon:
> >
> http://hothardware.com/Articles/WDs-1TB-Caviar-Green-w-Advanced-Format-Windows-XP-Users-Pay-Attention/?page=2
> >
> > [*] I don't want to sound like I'm advertising for Seagate here,
> > but at least it seems that with SmartAlign the performance impact
> > will be much less, so it might not be worth the trouble of
> > re-partitioning drives that are already being used.
> >
> >        Wonko
> >
> 
> The problem with SmartAlign is that..*.* it's magic... once you run
> out of mana, you can kiss your data goodbye.
> 
> In other words, I tried to find how it works, but Seagate seems to be
> mum; and that is ungood. Without knowing how exactly the technology
> works, how can we be sure that it won't blow up when encountering
> edge/corner cases?
> 
> So, albeit nice (in the sense that one does not have to experience the
> headache in ensuring that partitions are properly aligned), I
> personally will stay away from magical things.

Heretic!!

Beleive the magic you muggle!!

:-)




-- 
Alan McKinnnon
alan.mckinnon@gmail.com

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

[Joshua Murphy]

On Mon, Mar 5, 2012 at 11:00 AM, Alex Schuster <wonko@wonkology.org> wrote:
> Grant writes:
>
>> > 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
>
> Neither fdisk nor hdparm seem to get the correct sector size, at least
> not always. That's what I read somewhere (and not only once), and it's
> true for my own 2TB drive which I know to have a 4K sector size. I'd say
> you have to look up the specs on the vendor's web size to be sure.
>
>> So it doesn't matter where the first partition starts?
>
> If you have 4K sectors (and not a Seagate drive with SmartAlign [*]), it
> does.
>
> BTW, here's some benchmarks I just stumbled upon:
> http://hothardware.com/Articles/WDs-1TB-Caviar-Green-w-Advanced-Format-Windows-XP-Users-Pay-Attention/?page=2
>
> [*] I don't want to sound like I'm advertising for Seagate here, but at
> least it seems that with SmartAlign the performance impact will be
> much less, so it might not be worth the trouble of re-partitioning drives
> that are already being used.
>
>        Wonko

Also, it counts with SSDs, where alignment,or lack therof, with the
erase block becomes noticeable on write performance. Finding the
actual size of an erase block for most SSDs is rather difficult, but
1MB tends to be a reliable guess as a multiple of *that* as well.

-- 
Poison [BLX]
Joshua M. Murphy

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

[Mark Knecht]

On Sun, Mar 4, 2012 at 6:06 PM, Pandu Poluan <pandu@poluan.info> wrote:
>
> On Mar 5, 2012 4:59 AM, "Grant" <emailgrant@gmail.com> wrote:
>>
>>
>> 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?
>>
>
> Older BIOSes don't understand that hard disks now can have 4KiB sectors, so
> some of the "advanced format" hard disks report a sector size of 512B. But
> behind the scenes, the hard disk maps the logical sector to a subsector of
> the physical sector.
>
> The only sure fire way to find out if your hard disk uses 4KiB sectors is to
> open your computer and eyeball the hard disk. All 4KiB hard disks that I
> know of have statements on their surface that tell me so.
>
> Rgds,

I think I must be kind of late to this conversation, but as background
consider hdparm -i coupled with Google for the actual spec:

c2stable ~ # hdparm -i /dev/sdg

/dev/sdg:

 Model=WDC WD10EARS-00Z5B1, FwRev=80.00A80, SerialNo=WD-WCAVU0415076
 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=50
 BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=off
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=1953525168
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio3 pio4
 DMA modes:  mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: Unspecified:  ATA/ATAPI-1,2,3,4,5,6,7

 * signifies the current active mode

c2stable ~ #

With the model number it takes only a minute to determine that this WD
drive is a 4K sector drive. (Which is marked on the drive, as you
state, but I'd have to remove it to find that out.)

Now, in terms of performance, the only requirement (as I understand
it) is that all drive partition be aligned to sector addresses
divisible by 8. (512 * 8 = 4K) The reason 63 gives low performance is
because it's not naturally aligned by 8. With older versions of fdisk
if I started the first partition at 64 then the performance was fine
and only one sector was wasted.

M$, for whatever reason, decided to start at 2048, which is divisible
by 8, reserving the area at the front of the drive for (I think) their
boot loader and other M$-y things. My understanding of why fdisk now
enforces this is simply to be more careful about not overwriting the
M$ boot loaderif it's there. (But I could be very wrong about that!)
Remember, it's possible to make a dual boot system using M$'s loader
instead of grub, and important that fdisk doesn't mangle it when
someone is using that tool.

Just my views,
Mark