From owner-cvs-all Sun Sep 19 10:17:19 1999 Delivered-To: cvs-all@freebsd.org Received: from proxy2.ba.best.com (proxy2.ba.best.com [206.184.139.14]) by hub.freebsd.org (Postfix) with ESMTP id 7A4FB14CD3; Sun, 19 Sep 1999 10:16:45 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com ([209.157.86.2]) by proxy2.ba.best.com (8.9.3/8.9.2/best.out) with ESMTP id KAA26521; Sun, 19 Sep 1999 10:15:47 -0700 (PDT) Received: (from dillon@localhost) by apollo.backplane.com (8.9.3/8.9.1) id KAA72822; Sun, 19 Sep 1999 10:15:47 -0700 (PDT) (envelope-from dillon) Date: Sun, 19 Sep 1999 10:15:47 -0700 (PDT) From: Matthew Dillon Message-Id: <199909191715.KAA72822@apollo.backplane.com> To: Poul-Henning Kamp Cc: dg@root.com, Greg Lehey , cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: User block device access (was: cvs commit: src/sys/miscfs/specfs spec_vnops.c src/sys/sys vnode.h src/sys/kern vfs_subr.c) References: <15064.937728650@critter.freebsd.dk> Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk :My position is a little bit more flexible: I don't care which of :the two interfaces we retain, as long as we only have one and as :long as it isn't buggy (ie: it should return write errors). : :The argument for the block device is that it *is* more "unix feel" to :be able to read and write at any byte and with any length. : :IFF we want to maintain the block interface, we need to fix the error :return for the write case, but we also need to do a significant amount :of work speeding it up. It currently is an order of magnitude slower :than the char interface (remember to measure consumed CPU time, not :wall-clock time). : :For anyone with a second disk or floppy drive in their system, attempting :to fix the block dev interface is not a very hard problem. : :-- :Poul-Henning Kamp FreeBSD coreteam member The buffered block device is not slow, I don't know where you get that idea from. It is, in fact, just about as fast as you can get and still cache the data, which is to say somewhat faster then normal file access would be. The cache is flushed on every open of the device which may be causing your confusion. There is no overhead beyond the normal overhead associated with caching a file. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message