From owner-freebsd-fs Fri Jan 31 8:51: 0 2003 Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 55BE737B401 for ; Fri, 31 Jan 2003 08:50:59 -0800 (PST) Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id 398EA43F43 for ; Fri, 31 Jan 2003 08:50:58 -0800 (PST) (envelope-from phk@freebsd.org) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.12.6/8.12.6) with ESMTP id h0VGor4W002640; Fri, 31 Jan 2003 17:50:54 +0100 (CET) (envelope-from phk@freebsd.org) To: Steve Byan Cc: freebsd-fs@freebsd.org, tech-kern@netbsd.org Subject: Re: DEV_B_SIZE From: phk@freebsd.org In-Reply-To: Your message of "Fri, 31 Jan 2003 11:30:18 EST." <4912E0FE-3539-11D7-B26B-00306548867E@maxtor.com> Date: Fri, 31 Jan 2003 17:50:53 +0100 Message-ID: <2639.1044031853@critter.freebsd.dk> Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org In message <4912E0FE-3539-11D7-B26B-00306548867E@maxtor.com>, Steve Byan writes : >I'd appreciate hearing examples where hiding the underlying physical >block size would break a file system, database, transaction processing >monitor, or whatever. Please let me know if I may forward your reply >to the committee. Thanks. If by "hide" you mean that there will be no way to discover the smallest atomic unit of writes, then you are right: it would be bad. Provided we can get the size of the smallest atomic unit of writes in a standardized, documented, mandatory way, we will have no problem coping with it: Using a 4k size is no problem for our current filesystem technologies and device sizes. It was my impression that already many drives write entire tracks as atomic units, at least we have had plenty of anecdotal evidence to this effect ? Poul-Henning (FreeBSD's disk-I/O wizard) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message