From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261824AbULUSIy (ORCPT ); Tue, 21 Dec 2004 13:08:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261826AbULUSIy (ORCPT ); Tue, 21 Dec 2004 13:08:54 -0500 Received: from wproxy.gmail.com ([64.233.184.195]:17656 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S261824AbULUSIw (ORCPT ); Tue, 21 Dec 2004 13:08:52 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type:content-transfer-encoding; b=uj/vuZW5Vz541eaDBDR0ySWpEIbjr4hmTNG2BZUJ+K8Etx0ZcXy3gAMOmEmDORDpPGk4JFdajR4/QQP052eQIqTdrh6AExk8JwwYxMgtM072FOUZKv0b/hpvFHzufmZYJN4bwHoOdJ/htIL6pk5f8jCTMkFXskRIFfbm8PucxSQ= Message-ID: <1bdcbebf04122110087de9d976@mail.gmail.com> Date: Tue, 21 Dec 2004 11:08:51 -0700 From: Chris Swanson Reply-To: Chris Swanson To: linux-kernel@vger.kernel.org Subject: Make changes to read-only file system using RAM Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, Has anyone seen any work done on a RAM based file system that stores only changes to what would otherwise have been a read-only file system? For example, live Linux CD's rely on RAM file systems to store directories/files that must be modified, but the majority of the system is mounted read-only on the CD. I was thinking it would be really nice if we could mount a read-only medium (like a CD) in read-write mode, and store only modifications in RAM. This could give the illusion of a true read-write medium, and the RAM file system would just grow as more changes are made. I have searched around a bit and found nothing like this. Unfortunately, I have no kernel programming experience (although I'd love to learn). I was wondering if anyone has tried something similar in the past. Also, if anyone with more experience can see any reason why this is impossible or impractical, I would love to hear it, before I come to the same conclusion many months down the line. Thanks for your time, Chris