From owner-freebsd-hackers Tue Mar 3 16:14:08 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id QAA25795 for freebsd-hackers-outgoing; Tue, 3 Mar 1998 16:14:08 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from sendero.simon-shapiro.org (sendero-fxp0.Simon-Shapiro.ORG [206.190.148.34]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id QAA25575 for ; Tue, 3 Mar 1998 16:13:25 -0800 (PST) (envelope-from shimon@sendero-fxp0.simon-shapiro.org) Received: (qmail 19991 invoked by uid 1000); 4 Mar 1998 00:13:30 -0000 Message-ID: X-Mailer: XFMail 1.3-alpha-021598 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <199803032147.WAA03990@yedi.iaf.nl> Date: Tue, 03 Mar 1998 16:13:29 -0800 (PST) Reply-To: shimon@simon-shapiro.org Organization: The Simon Shapiro Foundation From: Simon Shapiro To: Wilko Bulte Subject: Re: SCSI Bus redundancy... Cc: grog@lemis.com, hackers@FreeBSD.ORG, blkirk@float.eli.net, jdn@acp.qiv.com, tlambert@primenet.com, sbabkin@dcn.att.com Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 03-Mar-98 Wilko Bulte wrote: ... > The trick is cute, but it was used to park heads in the drives I saw. > Not for flushing on drive caches. There would not be enough power to > do e.g. a seek in order flush the cache. And by definition your platter > rpm is dead wrong, you essentially use the whole thing as a > electromagnetic brake. Not nice. I could swear the old Priam 14" had something like 0.5 sec before RPM will degrad. And I am pretty sure it could flush all 2K of cache (2 seeks and two rotations worst case with 1k sectors), but I could be wrong. Most modern drives use the motor as an electromagnetic break. Try to snap off the motor leads and you see the difference in spin-down time. I have :-) ---------- Sincerely Yours, Simon Shapiro Shimon@Simon-Shapiro.ORG Voice: 503.799.2313 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message