Hi all
I am newbie to linux kernel. What is the use of /dev/zero.
Why it is created and how to use it
regards
Blesson Paul
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On Fri, 2002-04-12 at 08:46, blesson paul wrote:
> Hi all
> I am newbie to linux kernel. What is the use of /dev/zero.
> Why it is created and how to use it
> regards
> Blesson Paul
>
>
>
> _________________________________________________________________
> Chat with friends online, try MSN Messenger: http://messenger.msn.com
>
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>
Hi,
/dev/zero is a data source. It delivers zeroes ( maybe that's why this
name ;-).
BTW: You are new to the linux kernel or new to linux / unix?
Regards
Frank
Just as a matter of interest myself...what is it's actual function? It
is used during kernel debugging to supply an input?
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Frank Schaefer
Sent: 12 April 2002 08:19
To: [email protected]
Subject: Re: /dev/zero
On Fri, 2002-04-12 at 08:46, blesson paul wrote:
> Hi all
> I am newbie to linux kernel. What is the use of
/dev/zero.
> Why it is created and how to use it
> regards
> Blesson Paul
>
>
>
> _________________________________________________________________
> Chat with friends online, try MSN Messenger: http://messenger.msn.com
>
> -
> To unsubscribe from this list: send the line "unsubscribe
linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
Hi,
/dev/zero is a data source. It delivers zeroes ( maybe that's why this
name ;-).
BTW: You are new to the linux kernel or new to linux / unix?
Regards
Frank
It's just zeroes, so it allows you to test raw write speed on any
device:
dd if=/dev/zero of=/dev/hda to test your performances of hda ...
normally if I get it well, /dev/zero can't be you're bottleneck.
Sam
On Fri, Apr 12, 2002 at 08:26:22AM +0100, Rowan Ingvar Wilson wrote:
> Just as a matter of interest myself...what is it's actual function? It
> is used during kernel debugging to supply an input?
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Frank Schaefer
> Sent: 12 April 2002 08:19
> To: [email protected]
> Subject: Re: /dev/zero
>
> On Fri, 2002-04-12 at 08:46, blesson paul wrote:
> > Hi all
> > I am newbie to linux kernel. What is the use of
> /dev/zero.
> > Why it is created and how to use it
> > regards
> > Blesson Paul
> >
> >
> >
> > _________________________________________________________________
> > Chat with friends online, try MSN Messenger: http://messenger.msn.com
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe
> linux-kernel" in
> > the body of a message to [email protected]
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at http://www.tux.org/lkml/
> >
> Hi,
>
> /dev/zero is a data source. It delivers zeroes ( maybe that's why this
> name ;-).
>
> BTW: You are new to the linux kernel or new to linux / unix?
>
> Regards
> Frank
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel"
> in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
Samuel Maftoul a ?crit:
Samuel> It's just zeroes, so it allows you to test raw write speed on any
Samuel> device:
Samuel> dd if=/dev/zero of=/dev/hda to test your performances of hda ...
Samuel> normally if I get it well, /dev/zero can't be you're bottleneck.
Samuel> Sam
Just to save Samuel's soul ;-)
the dd command supplied above will erase your primary hard drive
To see hard drive performances, hdparm -tT /dev/hda is better.
PS: Pas sympa Samuel
--
Guillaume Gimenez
On Fri, Apr 12, 2002 at 05:12:06PM +0200, Guillaume Gimenez wrote:
> Samuel Maftoul a ?crit:
> Samuel> It's just zeroes, so it allows you to test raw write speed on any
> Samuel> device:
> Samuel> dd if=/dev/zero of=/dev/hda to test your performances of hda ...
> Samuel> normally if I get it well, /dev/zero can't be you're bottleneck.
> Samuel> Sam
oops really sorry, It will really earase your disk.
This morning I was really sleepy and wanted to write something other:
time dd if=/dev/zero of=/mnt/ bs=1024 count=100000
and so you can know what's the speed not of your ide or scsi (or
something other) which is given by hdparm but it will give you the speed
through the used filesystem.
Sorry about that.
Sam
>
> Just to save Samuel's soul ;-)
> the dd command supplied above will erase your primary hard drive
>
> To see hard drive performances, hdparm -tT /dev/hda is better.
>
> PS: Pas sympa Samuel
>
> --
> Guillaume Gimenez