Subject: Re: VM problems
To: Mark F Willey <>
From: Bill Studenmund <>
List: current-users
Date: 07/28/1995 17:22:51
On Fri, 28 Jul 1995, Mark F Willey wrote:

> "In a previous message, Bill Studenmund wrote:"
> > 
> > Could a process-memory limit (ULIMIT ?) be set lower than 16 Meg (or even
> > to exactly 16 Meg)? To test this out, try running 10 of the 8 meg 
> > versions. :-)
> AFAIK, NetBSD does something called "copy-on-write", which basically means
> that X copies of a program won't take up (size * X) amount of memory.
> They will just take up (size) of memory.
> (plus overhead, maybe)  If the program writes to the image, then, I think
> it will "copy" it, and split that process's text space off.  I'm sure
> someone else here could explain it better!  ;-)

Ok, but won't they each have a copy of the data each one malloc's? The 
program would allocate x meg of data, and then it wrote to the 
data it'd allocated. Thus even if the system had a delayed-allocation
method, it'd have to allocate the memory from vm.

> Mark

Take care,


P.S. I must really be far down on the majordomo list. I still haven't 
gotten my copy of my posting, and yet you've followed it up. Hmm.