From: Michal Suchanek <hramrach@...>
Date: 2007-05-14T19:49:19+09:00
Subject: Re: DRb connection error with more than 250+ DRb services

On 14/05/07, Thomas Hurst <tom.hurst@clara.net> wrote:
> * Michal Suchanek (hramrach@centrum.cz) wrote:
>
> >  I wonder why such limits are imposed. It is probably some workaround
> >  for a flaw in UNIX design that introduces possible DoS by exhausting
> >  kernel memory/structures. Maybe it was fixed in some kernels (if
> >  that's even possible) but nobody cared to fix the limit as well.
>
> How would you propose to avoid letting users exhaust system resources
> without limits of some sort?  Sadly the real world implementations of
> turing machines don't generally include unlimited tape...
>
> Modest default limits are a good thing, since they help reduce the
> impact of runaways, leaks and, indeed, DoS attempts.  This is as true in
> *ix as it is in any other system.
>

Sure it is avoidable. In a system where memory is allocated to users
(not somehow vaguely pooled), and the networking service is able to
back its socket data structures by user memory you only care about
memory, not what the user uses it for. The user then can store files,
sockets, or anything else that he wishes.
Of course, this probably would not happen on a POSIX system.

Thanks

Michal