From owner-freebsd-hackers Thu Aug 27 15:35:22 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id PAA17111 for freebsd-hackers-outgoing; Thu, 27 Aug 1998 15:35:22 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dingo.cdrom.com (dingo.cdrom.com [204.216.28.145]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id PAA17086 for ; Thu, 27 Aug 1998 15:35:10 -0700 (PDT) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost.cdrom.com [127.0.0.1]) by dingo.cdrom.com (8.9.1/8.8.8) with ESMTP id PAA00757; Thu, 27 Aug 1998 15:32:09 GMT (envelope-from mike@dingo.cdrom.com) Message-Id: <199808271532.PAA00757@dingo.cdrom.com> X-Mailer: exmh version 2.0.2 2/24/98 To: zhihuizhang cc: hackers Subject: Re: FFS questions In-reply-to: Your message of "Thu, 27 Aug 1998 12:20:14 -0400." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 27 Aug 1998 15:32:09 +0000 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > I am reading the source code in fs.h and the parameter fs_cpc confuses me. > > The comment says it is the number of cylinders per *cycle* in position > table. What does the "cycle" mean? It's the size of the rotational offset table. Starting from position 0 on the disk, there are N cycles of fastest-next-block locations as you move across the disk. You only need to store one cycle in the offset table. The position table and all the optimisations related to second-guessing the behaviour of the disk are now pessimisations in most cases, and should be eliminated entirely. Doing this is quite a job of work, and at the moment we simply short-circuit them. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message