Re: copy-on-write

On Fri 2 May, 1997, Oskar Pearson <oskar@is.co.za> wrote:
>This means that if a 400M program forks and then execs another process,
>you don't need 800M of ram to do it, and all it does is insert a process
>into the process list (thus adding a little struct to a table).

but most systems won't let you 'over-commit' memory, so you do need
the swap. Those that fall into this boat that I know, are:

SunOS 4 - you need enough swap
Irix 5/6 - you can configure virtual swap, but it still needs it.
NetBSD - you need enough swap.

(Irix has alternatives to fork in order to do the job without
requiring the swap space, but that's specific to them obviously)

-- jrg.
Received on Tue Jul 29 2003 - 13:15:41 MDT