Re: dump device

[Tigran Aivazian]

On Fri, 30 Jun 2000 [e-mail] wrote:

> 
>      Please reply to [e-mail] I am not registered on the mailing
> list.
> 
> Hello,
>      Does Linux supports any kind of dump device ?
>      When there is uncertain hang/crash can we take the memory dump to
> diagnose the problem ?
>      What are the issues involved in writing such a utility ?
> 
> Thank You,
> 
> Nilesh

Recently Werner Almesberger wrote an excellent paper on booting Linux in
general and on i386 in particular:

ftp://icaftp.epfl.ch/pub/people/almesber/misc/ols2k-9.ps.gz

In this paper he describes a dual-kernel mechanism where a small kernel
for raking the crashdump is preloaded along with a initrd and when we
panic the preloaded stuff is verified and that kernel is launched to do
the actual coredump.

http://www.missioncriticallinux.com/technology/coredump/

I didn't know that MCL's coredump uses such an interesting idea - I
thought it was a classical attempt to either:

a) use normal device drivers anyway

or

b) add a "polling io" entry points to block device layer which would work
   even if interrupt-driven mechanisms are failing

So, perhaps, one day I will try it out :)

Regards,
Tigran