[plt-scheme] Re: eq and hashing

The OS is responsible for managing limited, shared resources
for a set of possibly buggy, perhaps malicious client processes.

Certainly a program that has crashed cannot be dynamically using
a resource.  Nor can a program that has shut down gracefully.  In
either case, if the resource is no longer in use by any program, the
OS can reclaim it.



----- Original Message ----- 
From: "Zbyszek Jurkiewicz" <zbyszek at duch.mimuw.edu.pl>
To: "Joe Marshall" <jrm at ccs.neu.edu>
Cc: "Jerzy Karczmarczuk" <karczma at info.unicaen.fr>;
<plt-scheme at list.cs.brown.edu>
Sent: Monday, June 02, 2003 13:50
Subject: Re: [plt-scheme] Re: eq and hashing


>
>
> On Mon, 2 Jun 2003, Joe Marshall wrote:
>
> >   For list-related administrative tasks:
> >   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> >
> >
> > ----- Original Message ----- 
> > From: "Zbyszek Jurkiewicz" <zbyszek at duch.mimuw.edu.pl>
> >
> > > But...  we have laboratory in concurrent programming
> > > on Linux.  Students learn to use IPC mechanisms like semaphores,
> > > messages etc.  When a program crashes, all open files are closed.
> > > But IPC mechanism should also be deleted and they are not.  They
> > > stay in /tmp until their number reaches the limit.
> >
> > That's just an OS bug.
>
> I am afraid not, OS does not know whether some program is still
> using some gadget (in principle it possibly could) -- a "server"
> has to destroy it and is not obvious who is the server.
>
> Of course it has nothing to do with Scheme, I just wanted to show
> that such behavior is not necessarily "malicious" or stupid,
> but could be.
>
> Zbyszek Jurkiewicz
>
>