Date: Fri, 21 Mar 2008 12:15:47 +1100 From: Peter Jeremy <peterjeremy@optushome.com.au> To: Chuck Robey <chuckr@chuckr.org> Cc: FreeBSD-Hackers <freebsd-hackers@freebsd.org> Subject: Re: remote operation or admin Message-ID: <20080321011547.GA69011@server.vk2pj.dyndns.org> In-Reply-To: <47E16514.7090203@chuckr.org> References: <47DF1045.6050202@chuckr.org> <20080318082816.GA74218@eos.sc1.parodius.com> <47E146F9.5060105@chuckr.org> <20080319172213.GA28075@eos.sc1.parodius.com> <47E1558A.2030107@chuckr.org> <20080319184244.GA29838@eos.sc1.parodius.com> <47E16514.7090203@chuckr.org>
next in thread | previous in thread | raw e-mail | index | archive | help
--+HP7ph2BbKc20aGI Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Mar 19, 2008 at 03:10:12PM -0400, Chuck Robey wrote: >it might be possible to find some way to extend the work domain of an smp >system to stretch across machine lines, to jump across motherboards. Maybe >not to be global (huge latencies scare me away), but what about just going >3 feet, on a very high speed bus, like maybe a private pci bus? Not what >is, what could be? This is definitely possible. DEC built a memory channel adapter which allowed multiple AlphaServers to share (part of) each other's RAM. You could also try looking at Amoeba - it is a cross between a "traditional" SMP system and a cluster. There's probably no reason why you couldn't build a kernel module to "share" RAM between hosts using Ethernet or similar - though it would be much slower than accessing local RAM. >small, but with a bunch of bandwidth. So, in that case, what really are >the differences between smp and clustering, besides the raw current size of >the implementation? Are there huge basic differences between the >clustering concept and by smp's actual tasks? The access time differences between local and remote RAM mean that there are different trade-offs: Memory coherence is extremely expensive so more effort is expended in avoiding operations that require coherence. In general tasks that work well in a clustered environment have very low inter-process communication requirements. --=20 Peter Jeremy Please excuse any delays as the result of my ISP's inability to implement an MTA that is either RFC2821-compliant or matches their claimed behaviour. --+HP7ph2BbKc20aGI Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.8 (FreeBSD) iEYEARECAAYFAkfjDEMACgkQ/opHv/APuIc65wCfcgbQTBbiTKgRbozJmTkYRDho WzMAn1stcC68WpWWqu57rBMkNXSOReHl =CQEP -----END PGP SIGNATURE----- --+HP7ph2BbKc20aGI--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20080321011547.GA69011>