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From: Terry Lambert <terry@lambert.org>
Message-Id: <199511071844.LAA18058@phaeton.artisoft.com>
Subject: Re: kernel MIT-SHM extensions ??
To: pecold@abrcp.cz
Date: Tue, 7 Nov 1995 11:44:45 -0700 (MST)
Cc: freebsd-questions@freebsd.org
In-Reply-To: <199511071456.PAA23692@abrcp.abrcp.cz> from "Petr Kodl" at Nov 7, 95 03:56:10 pm
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> What's the MIT-SHM kernel extension ??

	It's an extension to the X transport mechanism so that locally
	running apps with Xlib can directly access memory instead of
	having to use the standard (slower) IPC mechanisms of net
	or POSIX domain sockets.

> Is it supported by 2.0.5 release kernel ??

	I believe you would need to rebuild a release kernel to add:

	#
	# These three options provide support for System V Interface
	# Definition-style interprocess communication, in the form of shared
	# memory, semaphores, and message queues, respectively.
	#
	options		SYSVSHM
	options		SYSVSEM
	options		SYSVMSG

	To your kernel configuration file to get shared memory support
	with 2.0.5.  Other than the underlying transport, it's entirely
	up to the X client and server if the extension is supported.

> If it is, how can I add it to the kernel configuration file ??

	See above.

> The X-server option does not change the behavior in this point, so 
> what is it exactly this option for ??

	Fast animation, mostly.  Like the X version of DOOM or ASCENT.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.