From owner-freebsd-hackers Fri Nov 16 2:12:52 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from piggy.rz.tu-ilmenau.de (piggy.rz.tu-ilmenau.de [141.24.4.8]) by hub.freebsd.org (Postfix) with ESMTP id 79C4D37B405 for ; Fri, 16 Nov 2001 02:12:46 -0800 (PST) Received: from gtw.hh59.local (pD9508BE7.dip.t-dialin.net [217.80.139.231]) (authenticated (0 bits)) by piggy.rz.tu-ilmenau.de (8.11.1/8.11.1) with ESMTP id fAGACg511227 (using TLSv1/SSLv3 with cipher EDH-RSA-DES-CBC3-SHA (168 bits) verified NO) Fri, 16 Nov 2001 11:12:44 +0100 (MET) Received: from walnut.hh59.local (walnut.hh59.local [192.168.2.10]) by gtw.hh59.local (8.11.3/8.11.3) with ESMTP id fAGALdK04908 (using TLSv1/SSLv3 with cipher EDH-RSA-DES-CBC3-SHA (168 bits) verified FAIL) for ; Fri, 16 Nov 2001 11:21:40 +0100 (CET) Received: (qmail 14233 invoked by uid 1000); 16 Nov 2001 10:13:06 -0000 Date: Fri, 16 Nov 2001 11:13:06 +0100 From: Martin Kaeske To: freebsd-hackers@freebsd.org Subject: BSD buffer management Message-ID: <20011116111306.A14218@walnut.hh59.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Hello Because i want to learn more about the BSD-kernel i bought the book "The Design and Implementation of the 4.4BSD Operating System" [McKusick, et.al.]. Now i come across the topic "Buffer Management" and i have a question: Is it possible that a call to bread() can result in a buffer covering more than one disk-block? If this is true how does the kernel ensures that there are no disk-blocks in more than one buffer (as the kernel does when files are shortened or removed)? Is it possible that its the callers (caller of bread()) task to keep track of overlapping buffers? And breads size argument is 'just' for flexibility and the caller has to ensure integrity. Martin -- The instructions said to use Windows 98 or better, so I installed FreeBSD. -- Jim Levie in comp.unix.bsd.freebsd.misc -- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message