Info about /dev/kmem required

Info about /dev/kmem required

[Milind]

Hi all

I wanted some info about ' /dev/kmem ' file with respect to following

1)  What this file contains?

2)  Who  writes into this file?

All I have found is that 'dmesg' will read from this file and display
system information.

Reply at the earliest.

Thanks
Milind

Re: Info about /dev/kmem required

[Erik Mouw]

On Fri, Aug 17, 2001 at 07:29:08PM +0530, Milind wrote:
> I wanted some info about ' /dev/kmem ' file with respect to following
> 
> 1)  What this file contains?

>From Documentation/devices.txt:

  1 char        Memory devices
                  1 = /dev/mem          Physical memory access
                  2 = /dev/kmem         Kernel virtual memory access

> 2)  Who  writes into this file?

Normally nobody does, though it can be used to patch up a running
system (in theory).

> Reply at the earliest.

I'm sorry, we're not a helpdesk.


Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
Phone: +31-15-2783635  Fax: +31-15-2781843  Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/

Re: Info about /dev/kmem required

[Frank Neuber]

On Fri, Aug 17, 2001 at 05:57:39PM -0400, Erik Mouw wrote:
> On Fri, Aug 17, 2001 at 07:29:08PM +0530, Milind wrote:
> > I wanted some info about ' /dev/kmem ' file with respect to following
> > 
> > 1)  What this file contains?
> 
> >From Documentation/devices.txt:
> 
>   1 char        Memory devices
>                   1 = /dev/mem          Physical memory access
>                   2 = /dev/kmem         Kernel virtual memory access
> 
> > 2)  Who  writes into this file?
> 
> Normally nobody does, though it can be used to patch up a running
> system (in theory).
> 
> > Reply at the earliest.
> 
> I'm sorry, we're not a helpdesk.

I think You can use /dev/kmem as an corefile for gdb. So it is possible to debug
the linux kernel (of course read only :-)).

 Frank
-- 
Dipl.-Ing. Elektrotechnik     convergence integrated media gmbh / HW
Frank Neuber                        Rosenthalerstr.51 / 10178 Berlin
Email:  neuber@convergence.de           Phone:  +49(0)30-72 62 06 50
WWW:    www.convergence.de              Fax:    +49(0)30-72 62 06 55

Re: Info about /dev/kmem required

[Erik Mouw]

On Mon, Aug 20, 2001 at 08:21:08PM +0200, Frank Neuber wrote:
> I think You can use /dev/kmem as an corefile for gdb. So it is
> possible to debug the linux kernel (of course read only :-)).

No, that's what /proc/kcore is for.


Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
Phone: +31-15-2783635  Fax: +31-15-2781843  Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/

Re: Info about /dev/kmem required

[Frank Neuber]

On Tue, Aug 21, 2001 at 02:39:54PM +0200, Erik Mouw wrote:
> On Mon, Aug 20, 2001 at 08:21:08PM +0200, Frank Neuber wrote:
> > I think You can use /dev/kmem as an corefile for gdb. So it is
> > possible to debug the linux kernel (of course read only :-)).
> 
> No, that's what /proc/kcore is for.
You are right!! Sorry it was my mistake.
 Frank

-- 
Dipl.-Ing. Elektrotechnik     convergence integrated media gmbh / HW
Frank Neuber                        Rosenthalerstr.51 / 10178 Berlin
Email:  neuber@convergence.de           Phone:  +49(0)30-72 62 06 50
WWW:    www.convergence.de              Fax:    +49(0)30-72 62 06 55