From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261167AbVFTBzh (ORCPT ); Sun, 19 Jun 2005 21:55:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261380AbVFTBzh (ORCPT ); Sun, 19 Jun 2005 21:55:37 -0400 Received: from wproxy.gmail.com ([64.233.184.199]:22426 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S261167AbVFTBz3 convert rfc822-to-8bit (ORCPT ); Sun, 19 Jun 2005 21:55:29 -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:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=iGrA6AjdTDK64ETBMIeQrerAXd7I4JZxfkpPrkO2jRVdqeQV98BgH8Tpv0/Q4FmRo6VX3g+XmBDjES94bHUAnXbiv+ESbEQzGwB73Ln4XalNAPq+wKTs3U8IlX0d40mwmi7U6o6WPxc2n64mO312nsM7e5C66U7KyGvgTduGMts= Message-ID: Date: Mon, 20 Jun 2005 09:55:29 +0800 From: guorke Reply-To: guorke To: linux-os@analogic.com Subject: Re: mabye simple,but i confused Cc: linux-kernel@vger.kernel.org In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Thanks,I must read it carefully On 6/16/05, Richard B. Johnson wrote: > On Thu, 16 Jun 2005, guorke wrote: > > > in understangding the linux kernel, the authors says > > "..Moves itself from address 0x00007c00 to address 0x00090000.." > > > > What i confused is why the Boot Loader do this, i asked google,but > > still no answe. > > who can make me understand it ? > > Thanks. > > The IBM 'IPL' (initial program load) address was specified to be > at 7c00. There was room here for only one "sector", which in the > early days was 512 bytes. The very first sector, the boot sector, > was loaded into this address and then execution was started at > a specified offset so that this boot code could load the rest > of the operating system. To load the rest of the operating system, > one needs to move the boot-code to somewhere it won't get > overwritten by subsequent reads from the disk. > > To load Linux, the boot developers wanted to load code 64k at > a time. The only address in real-mode, that was guaranteed to > not be in use, where the boot code could load a whole 64k was > at 90000 hex. This provides a buffer from which the boot-loader > can copy 64k at a time into the protected-mode address space > starting at 0x00100000. The boot-loader uses real-mode BIOS > services to copy the code to the 1 megabyte address which can't > be reached in real mode. > > Cheers, > Dick Johnson > Penguin : Linux version 2.6.11.9 on an i686 machine (5537.79 BogoMips). > Notice : All mail here is now cached for review by Dictator Bush. > 98.36% of all statistics are fiction. >