From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1EMQHw-0002vl-Lo for qemu-devel@nongnu.org; Mon, 03 Oct 2005 09:23:28 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1EMQHu-0002v7-Pa for qemu-devel@nongnu.org; Mon, 03 Oct 2005 09:23:28 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1EMQBk-0000o6-0T for qemu-devel@nongnu.org; Mon, 03 Oct 2005 09:17:04 -0400 Received: from [206.46.252.42] (helo=vms042pub.verizon.net) by monty-python.gnu.org with esmtp (Exim 4.34) id 1EMPeU-0004Q2-0A for qemu-devel@nongnu.org; Mon, 03 Oct 2005 08:42:42 -0400 Received: from [192.168.0.102] ([151.203.222.48]) by vms042.mailsrvcs.net (Sun Java System Messaging Server 6.2 HotFix 0.04 (built Dec 24 2004)) with ESMTPA id <0INS00AVNBAPA5S1@vms042.mailsrvcs.net> for qemu-devel@nongnu.org; Mon, 03 Oct 2005 07:42:25 -0500 (CDT) Date: Mon, 03 Oct 2005 08:41:46 -0400 From: John Coiner Subject: Re: [Qemu-devel] [patch] non-blocking disk IO Message-id: <4341270A.1000908@stanfordalumni.org> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed Content-transfer-encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: magnus.damm@gmail.com Cc: qemu-devel@nongnu.org Magnus, I don't think the Windows 2000 install hack will ever be obsolete. The installer assumes that a hard disk will take nonzero time to read some data. QEMU always services a read in zero-guest-time. (With the nonblocking IO patch, zero-guest-time reads still occur, when the requested data is in the host's file cache.) I doubt the IDE spec allows Windows to make this assumption... but the assumption is there, and we work around it by adding a delay that's visible to the guest. -- John