From owner-freebsd-current Thu Apr 3 01:02:05 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id BAA07759 for current-outgoing; Thu, 3 Apr 1997 01:02:05 -0800 (PST) Received: from palrel1.hp.com (palrel1.hp.com [15.253.72.10]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id BAA07753 for ; Thu, 3 Apr 1997 01:02:00 -0800 (PST) Received: from fakir.india.hp.com (fakir.india.hp.com [15.10.40.3]) by palrel1.hp.com with ESMTP (8.7.5/8.7.3) id BAA19366 for ; Thu, 3 Apr 1997 01:01:55 -0800 (PST) Received: from localhost by fakir.india.hp.com with SMTP (1.37.109.20/15.5+ECS 3.3) id AA060449937; Thu, 3 Apr 1997 14:32:17 +0500 Message-Id: <199704030932.AA060449937@fakir.india.hp.com> To: "Peter M. Chen" Cc: freebsd-current@freebsd.org Subject: Re: question on buffer cache and VMIO In-Reply-To: Your message of "Tue, 01 Apr 1997 22:15:03 EST." Date: Thu, 03 Apr 1997 14:32:16 +0500 From: "A JOSEPH KOSHY" Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk >>>> ""Peter M. Chen"" writes > The only hardware is a battery. The VM write protection is software. > Those without batteries need to write to disk (or non-volatile memory); > those with batteries (e.g. machine rooms, laptops) can keep data in memory > if it survives crashes. If I understood the paper correctly, Vista first copies out the protected address range to RIO protected memory prior to allowing the application to proceed with its changes. Would some form of copy-on-write scheme help to eliminate this initial copy? Whether there would be a performance benefit from this would depend on the relative costs of copying vs creating a set of mappings, I guess. Koshy My Personal Opinions Only