From: cgf AT bbc DOT com (Christopher Faylor)
Subject: Re: Crazy fork idea
2 Apr 1998 16:56:08 -0800
Message-ID: <EqtAp6.703.cygnus.cygwin32.developers@bbc.com>
References: <199804022354 DOT PAA00556 AT rtl DOT cygnus DOT com>
Reply-To: cgf AT bbc DOT com
To: cygwin32-developers AT cygnus DOT com

In article <199804022354 DOT PAA00556 AT rtl DOT cygnus DOT com>,
Geoffrey Noer  <noer AT cygnus DOT com> wrote:
>I was reading the Win32 multi-threaded O'Reilly book and got a crazy
>idea that may not be of benefit, but I'm not sure so I'll mention it.
>
>We could use shared memory for information like fds and mark it copy
>on write.  Then, when the parent process forks a child, the child
>could just keep using the same shared memory until such a time as it
>alters the information, at which time the OS would automatically
>create a copy and have the child modify that instead.
>
>Opinions?

Somebody brought up something similar to this a while ago in the mailing
list.  I think that Sergey mentioned that copy-on-write is not available
under Windows 95.  Big surprise.  Otherwise, I think this would be perfect
for fork().

I've been wondering if it wouldn't be a good idea to have two versions of
cygwinb19.dll, though -- a Windows 95 version and a Windows NT version.

I'm hoping to take a look at fork() next week.  I have a couple of ideas
for speeding it up.  I think that it is possible to get by with fewer
"context switches".
-- 
http://www.bbc.com/	cgf AT bbc DOT com			"Strange how unreal
VMS=>UNIX Solutions	Boston Business Computing	 the real can be."