Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262074AbVEREGR (ORCPT ); Wed, 18 May 2005 00:06:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262077AbVEREGQ (ORCPT ); Wed, 18 May 2005 00:06:16 -0400 Received: from rproxy.gmail.com ([64.233.170.193]:60644 "EHLO rproxy.gmail.com") by vger.kernel.org with ESMTP id S262074AbVEREGL convert rfc822-to-8bit (ORCPT ); Wed, 18 May 2005 00:06:11 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=I8NVaTFhGKtoU5uaP53Cqe8BiqYwIoOEfB8QuqZv7US2zA10M8ggn8redN/6xQVmv9OVuSYyQnDSNhHPI2vXbEuwADYW5uXfQpnu6m9tKIzMv8pRmD/Z0bmVO1ixnDa9vISBjJ5m4YSd4R/mwbcC56x8zwsGtgcvAw2wv1XxfP4= Message-ID: <311601c9050517210657a20256@mail.gmail.com> Date: Tue, 17 May 2005 22:06:11 -0600 From: "Eric D. Mudama" Reply-To: "Eric D. Mudama" To: linux-kernel@vger.kernel.org Subject: Re: Disk write cache (Was: Hyper-Threading Vulnerability) In-Reply-To: <20050516111859.GB13387@merlin.emma.line.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <1115963481.1723.3.camel@alderaan.trey.hu> <20050515145241.GA5627@irc.pl> <200505151121.36243.gene.heskett@verizon.net> <20050516111859.GB13387@merlin.emma.line.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1045 Lines: 21 On 5/16/05, Matthias Andree wrote: > I've heard that drives would be taking rotational energy from their > rotating platters and such, but never heard how the hardware compensates > the dilation with decreasing rotational frequency, which also requires > changed filter settings for the write channel, block encoding, delays, > possibly stepping the heads and so on. I don't believe these stories > until I see evidence. I'm pretty sure that most drives out there will immediately attempt to safely retract or park the heads the instant that a power loss is detected. There's too much potential damage that can occur if the heads aren't able to safely retract to a landing zone or ramp, that trying to save "one more block of cached data" just isn't worth the risk. --eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/