From owner-freebsd-hackers@FreeBSD.ORG Fri Aug 26 13:24:47 2005 Return-Path: X-Original-To: freebsd-hackers@FreeBSD.ORG Delivered-To: freebsd-hackers@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1064816A41F; Fri, 26 Aug 2005 13:24:47 +0000 (GMT) (envelope-from m.ehinger@ltur.de) Received: from posty.gateway-inter.net (posty.gateway-inter.net [213.144.19.86]) by mx1.FreeBSD.org (Postfix) with ESMTP id AA32343D49; Fri, 26 Aug 2005 13:24:46 +0000 (GMT) (envelope-from m.ehinger@ltur.de) In-Reply-To: <20050821025614.O84830@sasami.jurai.net> To: "Matthew N. Dodd" Message-ID: From: m.ehinger@ltur.de Date: Fri, 26 Aug 2005 15:24:00 +0200 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII X-Mailman-Approved-At: Sat, 27 Aug 2005 11:55:07 +0000 Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Parking disk drive heads X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Aug 2005 13:24:47 -0000 Thanks for that works well. Is there a way to lock the drive in that state for some seconds? What if an read/write request resumes the drive right after it was unloaded and we are still in a "shock" situation, if the drive is resumed before we hit the ground? Thanks Maik "Matthew N. Dodd" 21.08.2005 09:12 An m.ehinger@ltur.de Kopie freebsd-hackers@FreeBSD.ORG Thema Re: Parking disk drive heads On Wed, 17 Aug 2005 m.ehinger@ltur.de wrote: > which is the correct way to park the hd head? The documentation will refer to this operation as "Unload". Standby (0xE2) or Standby Immediate (0xE0) would be the only way I can see to do this. (Sleep performs an unload as well, but is not useful for your purposes.) Some of the low power idle modes supported by the Hitachi 5k100 mention head retraction to the ramp position, which might be of use provided the feature is widely supported on new hardware. Many drives support an "Emergency Unload" but it only appears to be activated by power failure. Anyhow, here is a snippet that should get you going (on 6.x/CURRENT): %%% #include ... struct ata_ioc_request req; int fd; fd = open("/dev/ad0", O_RDONLY); memset(&req, 0, sizeof(struct ata_ioc_request)); req.u.ata.command = ATA_STANDBY_IMMEDIATE; req.flags = ATA_CMD_CONTROL; req.timeout = 5; ioctl(fd, IOCATAREQUEST, &req); close(fd); -- 10 40 80 C0 00 FF FF FF FF C0 00 00 00 00 10 AA AA 03 00 00 00 08 00