From owner-cvs-all Sun Sep 19 12:13:36 1999 Delivered-To: cvs-all@freebsd.org Received: from verdi.nethelp.no (verdi.nethelp.no [158.36.41.162]) by hub.freebsd.org (Postfix) with SMTP id D66DA14C3F for ; Sun, 19 Sep 1999 12:13:30 -0700 (PDT) (envelope-from sthaug@nethelp.no) Received: (qmail 44389 invoked by uid 1001); 19 Sep 1999 19:13:28 +0000 (GMT) To: dillon@apollo.backplane.com Cc: phk@critter.freebsd.dk, mjacob@feral.com, dg@root.com, grog@lemis.com, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: User block device access From: sthaug@nethelp.no In-Reply-To: Your message of "Sun, 19 Sep 1999 12:00:26 -0700 (PDT)" References: <199909191900.MAA73792@apollo.backplane.com> X-Mailer: Mew version 1.05+ on Emacs 19.34.2 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Date: Sun, 19 Sep 1999 21:13:28 +0200 Message-ID: <44387.937768408@verdi.nethelp.no> Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk > In fact, a memory-mappable buffered block device with write-through would > be much, much more useful to a database then a character device, and I > think it's only a two line patch to make mmap() work, and probably a > four line patch to implement write-through. It would be virtually > unbeatable... Possibly so. However, the database systems I'm used to would much rather control caching themselves rather than rely on the OS. This is a very old discussion - you'll find it in OS and DB papers at least 15 years ago. Finding the appropriate mechanisms that the OS can offer to the DBMS is *not* easy. Steinar Haug, Nethelp consulting, sthaug@nethelp.no To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message