From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <7e796feeedc8d5eaafbe5763d5fa8e09@caldo.demon.co.uk> From: Charles Forsyth To: 9fans@cse.psu.edu Subject: Re: [9fans] process migration In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="upas-gwvsmftdqwuqqwfdjwroahpoyq" Date: Thu, 18 Sep 2003 15:08:39 +0100 Topicbox-Message-UUID: 3cd74f2c-eacc-11e9-9e20-41e7f4b1d025 This is a multi-part message in MIME format. --upas-gwvsmftdqwuqqwfdjwroahpoyq Content-Disposition: inline Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit some years ago, with an early Plan 9, when i was still at the university, an undergraduate looked at process migration as his 3rd year and MEng project, using Plan 9 running on several loosely-coupled 68030 cards in an Eltec VME crate, with a PC running Plan 9 providing some form of monitoring and control. as a project it worked out quite well, and he'd got it to the stage where he could shift processes from one card to another. the student made any necessary kernel changes himself even though he hadn't touched any operating system before, with relatively little advice from me. (I'd done the Eltec port for an earlier frame-grabbing robot control project.) my view of OS-based process migration (outside rather specialised cases) before the project would have been quite well summed up by ron minnich's comment; i don't think it has changed much since then (outside rather specialised cases). --upas-gwvsmftdqwuqqwfdjwroahpoyq Content-Type: message/rfc822 Content-Disposition: inline Return-path: <9fans-admin@cse.psu.edu> Received: from punt-3.mail.demon.net by mailstore for forsyth@caldo.demon.co.uk id 19zz0L-0002De-99; Thu, 18 Sep 2003 13:39:30 +0000 Received: from [130.203.4.6] (helo=mail.cse.psu.edu) by punt-3.mail.demon.net with esmtp id 19zz0L-0002De-99 for forsyth@caldo.demon.co.uk; Thu, 18 Sep 2003 13:39:30 +0000 Received: by mail.cse.psu.edu (CSE Mail Server, from userid 60001) id 8DD4A19BCF; Thu, 18 Sep 2003 09:39:18 -0400 (EDT) Received: from psuvax1.cse.psu.edu (psuvax1.cse.psu.edu [130.203.18.6]) by mail.cse.psu.edu (CSE Mail Server) with ESMTP id B336919AEC; Thu, 18 Sep 2003 09:39:14 -0400 (EDT) X-Original-To: 9fans@cse.psu.edu Delivered-To: 9fans@cse.psu.edu Received: by mail.cse.psu.edu (CSE Mail Server, from userid 60001) id 81B2819AEC; Thu, 18 Sep 2003 09:38:32 -0400 (EDT) Received: from mailwasher-b.lanl.gov (mailwasher.lanl.gov [192.16.0.25]) by mail.cse.psu.edu (CSE Mail Server) with ESMTP id 7984919A23 for <9fans@cse.psu.edu>; Thu, 18 Sep 2003 09:38:30 -0400 (EDT) Received: from mailrelay2.lanl.gov (localhost.localdomain [127.0.0.1]) by mailwasher-b.lanl.gov (8.12.9/8.12.9/(ccn-5)) with ESMTP id h8IDcRqw012104 for <9fans@cse.psu.edu>; Thu, 18 Sep 2003 07:38:29 -0600 Received: from ccs-mail.lanl.gov (localhost.localdomain [127.0.0.1]) by mailrelay2.lanl.gov (8.12.9/8.12.9/(ccn-5)) with ESMTP id h8IDcRdT002561 for <9fans@cse.psu.edu>; Thu, 18 Sep 2003 07:38:27 -0600 Received: from maxroach.lanl.gov (maxroach.lanl.gov [128.165.250.187]) by ccs-mail.lanl.gov (8.12.9/8.12.9/(ccn-5)) with ESMTP id h8IDcQ7W002696 for <9fans@cse.psu.edu>; Thu, 18 Sep 2003 07:38:26 -0600 From: ron minnich To: 9fans@cse.psu.edu Subject: Re: [9fans] process migration In-Reply-To: <181e352f.0309172305.5c4b343d@posting.google.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Scanned-By: MIMEDefang 2.35 Sender: 9fans-admin@cse.psu.edu Errors-To: 9fans-admin@cse.psu.edu X-BeenThere: 9fans@cse.psu.edu X-Mailman-Version: 2.0.11 Precedence: bulk Reply-To: 9fans@cse.psu.edu List-Id: Fans of the OS Plan 9 from Bell Labs <9fans.cse.psu.edu> List-Archive: Date: Thu, 18 Sep 2003 07:38:26 -0600 (MDT) X-Spam-Status: No, hits=-2.0 required=5.0 tests=EMAIL_ATTRIBUTION,IN_REP_TO,QUOTED_EMAIL_TEXT, REPLY_WITH_QUOTES,USER_AGENT_PINE version=2.55 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) On Thu, 18 Sep 2003, Kamal R. Prasad wrote: > does it allow processes from moving from cpu server A to cpu server B > after executing from sometime on server A? how is this different from > UNIX? it's not, neither Plan 9 nor Unix support this in a general way. There are systems that support this in a limited way, however. People keep wanting migration across OS instances to work the way that it works on CPUs in an SMP. It doesn't, and never has, except in very special cases. It's easy to get the easy parts right, hard to get the hard parts right, and impossible to get the impossible parts right. Most people stop at easy and call it a day. ron --upas-gwvsmftdqwuqqwfdjwroahpoyq--