partitions

partitions

[Paul Gimpelj]

Is it possible to have more than 4 partitions on a 160gb ide drive?


thanks.

Re: partitions

[Paul Gimpelj]

thanks,
but is there not a way in the modern bios's to have a second primary
partition table after the first one?


----- Original Message -----
From: "Phil White" <cerise@armory.com>
To: "Paul Gimpelj" <pgimpelj@sympatico.ca>
Sent: Thursday, August 12, 2004 6:12 PM
Subject: Re: partitions


> Not primary partitions, but you can have lots of partitions in an extended
> partition.  I think the limit there is 32, giving a theoretical maximum of
> 128.
>
> -Phil/CERisE
>
> On Thu, Aug 12, 2004 at 05:57:48PM -0400, Paul Gimpelj wrote:
> > Is it possible to have more than 4 partitions on a 160gb ide drive?
> >
> >
> > thanks.
> >
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-smp" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: partitions

[Dr. Keith G. Bowden]

The usual maximum is four under most PC Bios.

Others vary.

Keith Bowden


----- Original Message -----
From: "Paul Gimpelj" <pgimpelj@sympatico.ca>
To: "Phil White" <cerise@armory.com>
Cc: "linux-smp" <linux-smp@vger.kernel.org>
Sent: Thursday, August 12, 2004 4:00 PM
Subject: Re: partitions


> thanks,
> but is there not a way in the modern bios's to have a second primary
> partition table after the first one?
>
>
> ----- Original Message -----
> From: "Phil White" <cerise@armory.com>
> To: "Paul Gimpelj" <pgimpelj@sympatico.ca>
> Sent: Thursday, August 12, 2004 6:12 PM
> Subject: Re: partitions
>
>
> > Not primary partitions, but you can have lots of partitions in an
extended
> > partition.  I think the limit there is 32, giving a theoretical maximum
of
> > 128.
> >
> > -Phil/CERisE
> >
> > On Thu, Aug 12, 2004 at 05:57:48PM -0400, Paul Gimpelj wrote:
> > > Is it possible to have more than 4 partitions on a 160gb ide drive?
> > >
> > >
> > > thanks.
> > >
> > >
> > > -
> > > To unsubscribe from this list: send the line "unsubscribe linux-smp"
in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-smp" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: partitions

[Urs Thuermann]

"Paul Gimpelj" <pgimpelj@sympatico.ca> writes:

> Is it possible to have more than 4 partitions on a 160gb ide drive?

Except for machines that can boot multiple OSs, there is no need for
many partitions on the drive.  All my machines have only one or two
partitions and use LVM or LVM2 with devmapper.

urs

partitions

[Vanalme Filip]

I'm not that familiar with partitions in Barebox. On my i.MX27 board, I now have :

barebox:/ devinfo
devices:
|----imx_serial0
|----cs0
|----ramfs0
|----devfs0
|----mem0 (defaultenv)
|----mem1 (mem)
|----imx_spi1
|----mc137830 (pmic)
|----mem2 (ram0)
|----imx_nand0
|----nand0 (nand0, nand_oob0, self_raw, env_raw, nand0.barebox, nand0.bareboxenv, nand0.kernel, nand0.root)
|----fec_imx0
|----miidev0 (phy0)
|----eth0

drivers:
imx_serial
     ramfs
     devfs
   fec_imx
    miidev
  imx_nand
 cfi_flash
   imx_spi
     imxfb
   mc13783
       mem
barebox:/

and :

barebox:/ ls -l /dev
cr-------- 4294967295 zero
crw-------       6125 defaultenv
crw------- 4294967295 mem
crw-------        256 pmic
crw-------  134217728 ram0
crw-------  268435456 nand0
cr--------    8388608 nand_oob0
crw-------         32 phy0
crw-------     262144 self_raw
crw-------     262144 self0
crw-------     131072 env_raw
crw-------     131072 env0
crw-------     262144 nand0.barebox
crw-------     131072 nand0.bareboxenv
crw-------    2097152 nand0.kernel
crw-------  265945088 nand0.root
barebox:/

I think this looks OK.
However, I expected this to work (I took this from descriptions on the Internet...) :

barebox:/ erase /dev/nand0.kernel.bb
stat /dev/nand0.kernel.bb: No such file or directory
barebox:/

and

barebox:/ tftp zImage /dev/nand0.kernel.bb
open: Read-only file system
barebox:/


Is there any documentation that handles/describes this ? (e.g. what's the extension .bb ?)


Filip



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Re: partitions

[Baruch Siach]

HI Vanalme,

On Mon, Feb 28, 2011 at 09:36:14AM +0100, Vanalme Filip wrote:
> barebox:/ erase /dev/nand0.kernel.bb
> stat /dev/nand0.kernel.bb: No such file or directory
> barebox:/
> 
> and
> 
> barebox:/ tftp zImage /dev/nand0.kernel.bb
> open: Read-only file system
> barebox:/
> 
> 
> Is there any documentation that handles/describes this ? (e.g. what's the extension .bb ?)

The .bb extension means a bad block aware partition. Use the 'nand -a' command 
to create one from a raw NAND partition, e.g. 'nand -a /dev/nand0.kernel'.

baruch

-- 
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=}------------------------------------------------ooO--U--Ooo------------{=
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RE: partitions

[Vanalme Filip]

> -----Original Message-----
> From: Baruch Siach [mailto:baruch@tkos.co.il]
> Sent: maandag 28 februari 2011 9:48
> To: Vanalme Filip
> Cc: barebox@lists.infradead.org
> Subject: Re: partitions
> 
> HI Vanalme,
> 
> On Mon, Feb 28, 2011 at 09:36:14AM +0100, Vanalme Filip wrote:
> > barebox:/ erase /dev/nand0.kernel.bb
> > stat /dev/nand0.kernel.bb: No such file or directory
> > barebox:/
> >
> > and
> >
> > barebox:/ tftp zImage /dev/nand0.kernel.bb
> > open: Read-only file system
> > barebox:/
> >
> >
> > Is there any documentation that handles/describes this ? (e.g. what's the
> extension .bb ?)
> 
> The .bb extension means a bad block aware partition. Use the 'nand -a' command
> to create one from a raw NAND partition, e.g. 'nand -a /dev/nand0.kernel'.
> 
> baruch

[Filip]  Thanks !


> 
> --
>                                                      ~. .~   Tk Open Systems
> =}------------------------------------------------ooO--U--Ooo------------{=
>    - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

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RE: partitions

[Vanalme Filip]

> -----Original Message-----
> From: barebox-bounces@lists.infradead.org [mailto:barebox-
> bounces@lists.infradead.org] On Behalf Of Vanalme Filip
> Sent: maandag 28 februari 2011 9:57
> To: Baruch Siach
> Cc: barebox@lists.infradead.org
> Subject: RE: partitions
> 
> > -----Original Message-----
> > From: Baruch Siach [mailto:baruch@tkos.co.il]
> > Sent: maandag 28 februari 2011 9:48
> > To: Vanalme Filip
> > Cc: barebox@lists.infradead.org
> > Subject: Re: partitions
> >
> > HI Vanalme,
> >
> > On Mon, Feb 28, 2011 at 09:36:14AM +0100, Vanalme Filip wrote:
> > > barebox:/ erase /dev/nand0.kernel.bb
> > > stat /dev/nand0.kernel.bb: No such file or directory
> > > barebox:/
> > >
> > > and
> > >
> > > barebox:/ tftp zImage /dev/nand0.kernel.bb
> > > open: Read-only file system
> > > barebox:/
> > >
> > >
> > > Is there any documentation that handles/describes this ? (e.g. what's the
> > extension .bb ?)
> >
> > The .bb extension means a bad block aware partition. Use the 'nand -a'
> command
> > to create one from a raw NAND partition, e.g. 'nand -a /dev/nand0.kernel'.
> >
> > baruch
> 
> [Filip]  Thanks !
> 

[Filip]  Shouldn't I have automatically /dev/mtdblock* devices, e.g. /dev/mtdblock7 for rootfs nand partition ?
> 
> >
> > --
> >                                                      ~. .~   Tk Open Systems
> > =}------------------------------------------------ooO--U--Ooo------------{=
> >    - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox

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Re: partitions

[Juergen Beisert]

Vanalme Filip wrote:
> I'm not that familiar with partitions in Barebox. On my i.MX27 board, I now
> have :
>
> barebox:/ devinfo
>
> devices:
> |----imx_serial0
> |----cs0
> |----ramfs0
> |----devfs0
> |----mem0 (defaultenv)
> |----mem1 (mem)
> |----imx_spi1
> |----mc137830 (pmic)
> |----mem2 (ram0)
> |----imx_nand0
> |----nand0 (nand0, nand_oob0, self_raw, env_raw, nand0.barebox,
> | nand0.bareboxenv, nand0.kernel, nand0.root) ----fec_imx0
> |----miidev0 (phy0)
> |----eth0
>
> drivers:
> imx_serial
>      ramfs
>      devfs
>    fec_imx
>     miidev
>   imx_nand
>  cfi_flash
>    imx_spi
>      imxfb
>    mc13783
>        mem
> barebox:/
>
> and :
>
> barebox:/ ls -l /dev
> cr-------- 4294967295 zero
> crw-------       6125 defaultenv
> crw------- 4294967295 mem
> crw-------        256 pmic
> crw-------  134217728 ram0
> crw-------  268435456 nand0
> cr--------    8388608 nand_oob0
> crw-------         32 phy0
> crw-------     262144 self_raw
> crw-------     262144 self0
> crw-------     131072 env_raw
> crw-------     131072 env0
> crw-------     262144 nand0.barebox
> crw-------     131072 nand0.bareboxenv
> crw-------    2097152 nand0.kernel
> crw-------  265945088 nand0.root
> barebox:/
>
> I think this looks OK.
> However, I expected this to work (I took this from descriptions on the
> Internet...) :
>
> barebox:/ erase /dev/nand0.kernel.bb
> stat /dev/nand0.kernel.bb: No such file or directory
> barebox:/
>
> and
>
> barebox:/ tftp zImage /dev/nand0.kernel.bb
> open: Read-only file system
> barebox:/
>
>
> Is there any documentation that handles/describes this ? (e.g. what's the
> extension .bb ?)

'bb' means "Bad Block", and defines a layer that is bad block aware, and can 
handle it in a correct manner.

Add "CONFIG_GLOB=y" to make a script work, that add the *.bb names to all 
existing nand partitions.

jbe

-- 
Pengutronix e.K.                              | Juergen Beisert             |
Linux Solutions for Science and Industry      | Phone: +49-8766-939 228     |
Vertretung Sued/Muenchen, Germany             | Fax:   +49-5121-206917-5555 |
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partitions

[Roberto Spadim]

hi guys, could we implement raid partitions?
for example:
mdadm --create /dev/md0 --level=1 --devices /dev/sda /dev/sdb
fdisk /dev/md0
create pratition 1,2,3,4

mkfs.ext4 /dev/md0p1
mkfs.ext4 /dev/md0p2
mkfs.ext4 /dev/md0p3
mkfs.ext4 /dev/md0p4

?? any idea? could we implement it?
there´s a TODO list for linux software raid?

-- 
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Spadim Technology / SPAEmpresarial
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Re: partitions

[Roberto Spadim]

i read about lvm (not a lot), it work with grub and lilo right?

2011/1/28 Doug Dumitru <doug@easyco.com>:
> This functionality already exists with two different solutions.
>
> The "normal" solution is to use LVM on top of /dev/md0.  LVM is usually
> considered "better" than partitions because it is a more flexible approach.
>
> If you have to have partitions, you can do this with:
>
>     ... create partitions 1,2,3,4
>     kpartx -a /dev/md0
>     mkfs.ext4 /dev/mapper/md0p1
>     mkfs.ext4 /dev/mapper/md0p2
>     mkfs.ext4 /dev/mapper/md0p3
>     mkfs.ext4 /dev/mapper/md0p4
>
> This is not really a "linux-raid" issue, but just how to apply block device
> mapping tools.
>
> Doug Dumitru
> EasyCo LLC
>
> On Fri, Jan 28, 2011 at 1:24 PM, Roberto Spadim <roberto@spadim.com.br>
> wrote:
>>
>> hi guys, could we implement raid partitions?
>> for example:
>> mdadm --create /dev/md0 --level=1 --devices /dev/sda /dev/sdb
>> fdisk /dev/md0
>> create pratition 1,2,3,4
>>
>> mkfs.ext4 /dev/md0p1
>> mkfs.ext4 /dev/md0p2
>> mkfs.ext4 /dev/md0p3
>> mkfs.ext4 /dev/md0p4
>>
>> ?? any idea? could we implement it?
>> there愀 a TODO list for linux software raid?
>>
>> --
>> Roberto Spadim
>> Spadim Technology / SPAEmpresarial
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
>
> --
> Doug Dumitru
> EasyCo LLC
>
>



-- 
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Re: partitions

[Doug Dumitru]

On Fri, Jan 28, 2011 at 1:45 PM, Roberto Spadim <roberto@spadim.com.br> wrote:
>
> i read about lvm (not a lot), it work with grub and lilo right?

grub and lilo need a "plain" boot partition.  the raid setup is later
and your root partition can definitely be inside of an LVM volume.
This is the default install for many distros.

Doug Dumitru
EasyCo LLC

>
> 2011/1/28 Doug Dumitru <doug@easyco.com>:
> > This functionality already exists with two different solutions.
> >
> > The "normal" solution is to use LVM on top of /dev/md0.  LVM is usually
> > considered "better" than partitions because it is a more flexible approach.
> >
> > If you have to have partitions, you can do this with:
> >
> >     ... create partitions 1,2,3,4
> >     kpartx -a /dev/md0
> >     mkfs.ext4 /dev/mapper/md0p1
> >     mkfs.ext4 /dev/mapper/md0p2
> >     mkfs.ext4 /dev/mapper/md0p3
> >     mkfs.ext4 /dev/mapper/md0p4
> >
> > This is not really a "linux-raid" issue, but just how to apply block device
> > mapping tools.
> >
> > Doug Dumitru
> > EasyCo LLC
> >
> > On Fri, Jan 28, 2011 at 1:24 PM, Roberto Spadim <roberto@spadim.com.br>
> > wrote:
> >>
> >> hi guys, could we implement raid partitions?
> >> for example:
> >> mdadm --create /dev/md0 --level=1 --devices /dev/sda /dev/sdb
> >> fdisk /dev/md0
> >> create pratition 1,2,3,4
> >>
> >> mkfs.ext4 /dev/md0p1
> >> mkfs.ext4 /dev/md0p2
> >> mkfs.ext4 /dev/md0p3
> >> mkfs.ext4 /dev/md0p4
> >>
> >> ?? any idea? could we implement it?
> >> there愀 a TODO list for linux software raid?
> >>
> >> --
> >> Roberto Spadim
> >> Spadim Technology / SPAEmpresarial
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
> >
> >
> > --
> > Doug Dumitru
> > EasyCo LLC
> >
> >
>
>
>
> --
> Roberto Spadim
> Spadim Technology / SPAEmpresarial



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Re: partitions

[Roberto Spadim]

humm.... ok... no problems i was think about making software raid 100%
compatible with hardware raid (transparently) but it´s not just a plug
and play, no problems it´s easy :)

2011/1/28 Doug Dumitru <doug@easyco.com>:
> On Fri, Jan 28, 2011 at 1:45 PM, Roberto Spadim <roberto@spadim.com.br> wrote:
>>
>> i read about lvm (not a lot), it work with grub and lilo right?
>
> grub and lilo need a "plain" boot partition.  the raid setup is later
> and your root partition can definitely be inside of an LVM volume.
> This is the default install for many distros.
>
> Doug Dumitru
> EasyCo LLC
>
>>
>> 2011/1/28 Doug Dumitru <doug@easyco.com>:
>> > This functionality already exists with two different solutions.
>> >
>> > The "normal" solution is to use LVM on top of /dev/md0.  LVM is usually
>> > considered "better" than partitions because it is a more flexible approach.
>> >
>> > If you have to have partitions, you can do this with:
>> >
>> >     ... create partitions 1,2,3,4
>> >     kpartx -a /dev/md0
>> >     mkfs.ext4 /dev/mapper/md0p1
>> >     mkfs.ext4 /dev/mapper/md0p2
>> >     mkfs.ext4 /dev/mapper/md0p3
>> >     mkfs.ext4 /dev/mapper/md0p4
>> >
>> > This is not really a "linux-raid" issue, but just how to apply block device
>> > mapping tools.
>> >
>> > Doug Dumitru
>> > EasyCo LLC
>> >
>> > On Fri, Jan 28, 2011 at 1:24 PM, Roberto Spadim <roberto@spadim.com.br>
>> > wrote:
>> >>
>> >> hi guys, could we implement raid partitions?
>> >> for example:
>> >> mdadm --create /dev/md0 --level=1 --devices /dev/sda /dev/sdb
>> >> fdisk /dev/md0
>> >> create pratition 1,2,3,4
>> >>
>> >> mkfs.ext4 /dev/md0p1
>> >> mkfs.ext4 /dev/md0p2
>> >> mkfs.ext4 /dev/md0p3
>> >> mkfs.ext4 /dev/md0p4
>> >>
>> >> ?? any idea? could we implement it?
>> >> there愀 a TODO list for linux software raid?
>> >>
>> >> --
>> >> Roberto Spadim
>> >> Spadim Technology / SPAEmpresarial
>> >> --
>> >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>> >> the body of a message to majordomo@vger.kernel.org
>> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> >
>> >
>> >
>> > --
>> > Doug Dumitru
>> > EasyCo LLC
>> >
>> >
>>
>>
>>
>> --
>> Roberto Spadim
>> Spadim Technology / SPAEmpresarial
>
>
>
> --
> Doug Dumitru
> EasyCo LLC
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>



-- 
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Re: partitions

[Hank Barta]

On Fri, Jan 28, 2011 at 4:39 PM, Doug Dumitru <doug@easyco.com> wrote:
>
> grub and lilo need a "plain" boot partition.  the raid setup is later
...

One exception: Grub (and perhaps LILO) can boot from a RAID1 partition
because the individual partition looks like a plain file system. It
requires v 0.9 metadata which stores the superblock at the end of the
partition. (Don't ask me how I know! ;) )

I have used LVM to partition a RAID5. I have no idea if it adds
significant overhead vs. partitioning the RAID itself if that were
possible. It was arcane enough for me to not care to do it again. It
appears to have some powerful capabilities that were not needed by me.

best,
hank

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Re: partitions

[Phillip Susi]

On 01/28/2011 08:22 PM, Hank Barta wrote:
> One exception: Grub (and perhaps LILO) can boot from a RAID1 partition
> because the individual partition looks like a plain file system. It
> requires v 0.9 metadata which stores the superblock at the end of the
> partition. (Don't ask me how I know! ;) )

Grub2 can boot from raid1, raid0, raid5, it doesn't care ( without a 
plain /boot partition ).

> I have used LVM to partition a RAID5. I have no idea if it adds
> significant overhead vs. partitioning the RAID itself if that were
> possible. It was arcane enough for me to not care to do it again. It
> appears to have some powerful capabilities that were not needed by me.

With LVM you can do online resize and moves, and don't run into issues 
trying to expand a partition and having to take forever to move an 
adjacent one over to make room, or other issues with the 4 primary 
partition limit.  I find these to be pretty handy.

Re: partitions

[Roberto Spadim]

nice i don't know if LVM make a more overhead but it's a very feature
=) thanks again guys!

2011/1/29 Phillip Susi <psusi@cfl.rr.com>:
> On 01/28/2011 08:22 PM, Hank Barta wrote:
>>
>> One exception: Grub (and perhaps LILO) can boot from a RAID1 partition
>> because the individual partition looks like a plain file system. It
>> requires v 0.9 metadata which stores the superblock at the end of the
>> partition. (Don't ask me how I know! ;) )
>
> Grub2 can boot from raid1, raid0, raid5, it doesn't care ( without a plain
> /boot partition ).
>
>> I have used LVM to partition a RAID5. I have no idea if it adds
>> significant overhead vs. partitioning the RAID itself if that were
>> possible. It was arcane enough for me to not care to do it again. It
>> appears to have some powerful capabilities that were not needed by me.
>
> With LVM you can do online resize and moves, and don't run into issues
> trying to expand a partition and having to take forever to move an adjacent
> one over to make room, or other issues with the 4 primary partition limit.
>  I find these to be pretty handy.
>
> --
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-- 
Roberto Spadim
Spadim Technology / SPAEmpresarial
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Re: partitions

[Phillip Susi]

It already is.

On 01/28/2011 04:24 PM, Roberto Spadim wrote:
> hi guys, could we implement raid partitions?
> for example:
> mdadm --create /dev/md0 --level=1 --devices /dev/sda /dev/sdb
> fdisk /dev/md0
> create pratition 1,2,3,4
>
> mkfs.ext4 /dev/md0p1
> mkfs.ext4 /dev/md0p2
> mkfs.ext4 /dev/md0p3
> mkfs.ext4 /dev/md0p4
>
> ?? any idea? could we implement it?
> there´s a TODO list for linux software raid?
>

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partitions

[David Chow]

Hi all,

Is there any global variables or list in the kernel space that I can 
find out which partitions are available in the system? Please give 
pointer of information.

regards,
David

Re: partitions

[Mr. James W. Laferriere]

	Hello David ,  /proc/partitions ?  Hth ,  JimL

On Thu, 25 Jul 2002, David Chow wrote:
> Hi all,
> Is there any global variables or list in the kernel space that I can
> find out which partitions are available in the system? Please give
> pointer of information.
> regards,
> David

       +------------------------------------------------------------------+
       | James   W.   Laferriere | System    Techniques | Give me VMS     |
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       | babydr@baby-dragons.com | Coudersport PA 16915 |   only  on  AXP |
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Re: partitions

[Randy.Dunlap]

On Wed, 24 Jul 2002, Mr. James W. Laferriere wrote:

| 	Hello David ,  /proc/partitions ?  Hth ,  JimL
|
| On Thu, 25 Jul 2002, David Chow wrote:
| > Hi all,
| > Is there any global variables or list in the kernel space that I can
| > find out which partitions are available in the system? Please give
| > pointer of information.

um, I wouldn't call /proc/partitions "in the kernel space."
However, someone could clone the code that produces /proc/partitions
in kernel space.

in drivers/block/genhd.c::get_partition_list()  [at least in 2.4.18/19]

-- 
~Randy

Re: partitions

[Andries Brouwer]

On Thu, Jul 25, 2002 at 12:11:08AM +0800, David Chow wrote:

> Is there any global variables or list in the kernel space that I can 
> find out which partitions are available in the system?

Look at the struct gendisk chain.

Re: partitions

[Alexander Viro]

On Wed, 24 Jul 2002, Andries Brouwer wrote:

> On Thu, Jul 25, 2002 at 12:11:08AM +0800, David Chow wrote:
> 
> > Is there any global variables or list in the kernel space that I can 
> > find out which partitions are available in the system?
> 
> Look at the struct gendisk chain.

... and you will get a random set of things.  E.g. you might very well
find a gendisk shared by hda (with its partitions) and hdb (either
unpartitioned disk or a CDROM; no way to tell which one it is).  OTOH,
you will not find a SCSI CDROM.  You will find IDE-floppy.  You will not
find paride one.  You will find a very odd gendisk for RAID devices
(even though they are not partitioned).  You will not find one for loop
or nbd.

IOW, contents of /proc/partitions or (soon to be late) gendisk chain
is random - any code that relies on it to give you a meaningful set
of devices is buggered.

BTW, going through /proc/partitions and blindly opening all devices you
see is _NOT_ a good idea - it will show you absent devices if there is
something with the same major and higher minor.  Why?  Beats me.

Basically, gendisks are crap.  Why on the earth they were created as
per-major objects instead of per-disk ones is a mistery, but whatever
reason it had, it had acted as serious source of mess.  For many years.
Right now I'm cleaning that mess up in 2.5 and I have nothing nice to
say about the bright guys responsible for its creation.  Sorry.

Re: partitions

[Andries Brouwer]

On Wed, Jul 24, 2002 at 03:02:50PM -0400, Alexander Viro wrote:

> Basically, gendisks are crap.  Why on the earth they were created as
> per-major objects instead of per-disk ones is a mistery, but whatever
> reason it had, it had acted as serious source of mess.  For many years.
> Right now I'm cleaning that mess up in 2.5 and I have nothing nice to
> say about the bright guys responsible for its creation.  Sorry.

[amused] Good to see that you now understand that permanent
disk data is not stored in a struct block_device and that
the way to removal of the arrays is nearly independent of
struct block_device and instead dependent on a replacement
of struct gendisk.

[berating] However, your annoyed words are not fair to Drew Eckhardt.
Ten years ago, when he created struct gendisk, most of the problems
you mention did not exist yet.

Re: partitions

[David Chow]

Andries Brouwer wrote:
> On Wed, Jul 24, 2002 at 03:02:50PM -0400, Alexander Viro wrote:
> 
> 
>>Basically, gendisks are crap.  Why on the earth they were created as
>>per-major objects instead of per-disk ones is a mistery, but whatever
>>reason it had, it had acted as serious source of mess.  For many years.
>>Right now I'm cleaning that mess up in 2.5 and I have nothing nice to
>>say about the bright guys responsible for its creation.  Sorry.
> 
> 
> [amused] Good to see that you now understand that permanent
> disk data is not stored in a struct block_device and that
> the way to removal of the arrays is nearly independent of
> struct block_device and instead dependent on a replacement
> of struct gendisk.
> 
> [berating] However, your annoyed words are not fair to Drew Eckhardt.
> Ten years ago, when he created struct gendisk, most of the problems
> you mention did not exist yet.

Thanks for advice, it seems there are no standard solutions right? It 
depends on what sort of device we are looking for... I think I rather 
concentrate on finding local partitioncs, ide or scsi. But the case of 
ide-floppy is in a gray area. I certainly don't want to make use of such 
slow disk.

regards,
David