From owner-rawio@oss.sgi.com Mon Feb 7 10:01:37 2000 Received: by oss.sgi.com id ; Mon, 7 Feb 2000 10:01:17 -0800 Received: from barbar.esat.kuleuven.ac.be ([134.58.56.153]:44555 "EHLO barbar.esat.kuleuven.ac.be") by oss.sgi.com with ESMTP id ; Mon, 7 Feb 2000 10:01:15 -0800 Received: from galois.esat.kuleuven.ac.be (IDENT:dewin@galois.esat.kuleuven.ac.be [134.58.189.75]) by barbar (version 8.9.3) for with ESMTP id TAA17084; Mon, 7 Feb 2000 19:01:12 +0100 (MET) Organization: ESAT, K.U.Leuven, Belgium Date: Mon, 7 Feb 2000 19:08:10 +0100 (CET) From: Erik De Win Reply-To: erik.dewin@esat.kuleuven.ac.be To: rawio@oss.sgi.com Subject: request for information Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-rawio@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;rawio-outgoing Hello, I would like to obtain more information about the internals (or inexistence thereof) of raw devices. How is synchronization with the buffer cache guaranteed? In particular, say that I want to insert an intermediate (e.g. encryption) layer in between the buffer cache and the device driver; will raw I/O bypass this (I presume it will). Is there any possibility to prevent this (say that my hard disk is encrypted and I want to decrypt before any information is accessed)? Thank for any suggestions, Erik De Win ******************************************************************************* Erik De Win COSIC research group e-mail: erik.dewin@esat.kuleuven.ac.be K.U.Leuven voice: +32-(0)-16-32.18.85 K. Mercierlaan 94 fax: +32-(0)-16-32.19.69 B-3001 Heverlee www: http://www.esat.kuleuven.ac.be/~dewin/ ******************************************************************************* From owner-rawio@oss.sgi.com Mon Feb 7 13:01:09 2000 Received: by oss.sgi.com id ; Mon, 7 Feb 2000 13:00:59 -0800 Received: from sgi.SGI.COM ([192.48.153.1]:37458 "EHLO sgi.com") by oss.sgi.com with ESMTP id ; Mon, 7 Feb 2000 13:00:38 -0800 Received: from griffin.engr.sgi.com ([163.154.5.72]) by sgi.com (980327.SGI.8.8.8-aspam/980304.SGI-aspam: SGI does not authorize the use of its proprietary systems or networks for unsolicited or bulk email from the Internet.) via ESMTP id NAA00154 for ; Mon, 7 Feb 2000 13:00:19 -0800 (PST) mail_from (slurn@griffin.engr.sgi.com) Received: (from slurn@localhost) by griffin.engr.sgi.com (980427.SGI.8.8.8/960327.SGI.AUTOCF) id MAA78589; Mon, 7 Feb 2000 12:58:19 -0800 (PST) From: slurn@griffin.engr.sgi.com (Scott Lurndal) Message-Id: <200002072058.MAA78589@griffin.engr.sgi.com> Subject: Re: request for information To: erik.dewin@esat.kuleuven.ac.be Date: Mon, 7 Feb 2000 12:58:19 -0800 (PST) Cc: rawio@oss.sgi.com In-Reply-To: from "Erik De Win" at Feb 07, 2000 07:08:10 PM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-rawio@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;rawio-outgoing > > Hello, > > I would like to obtain more information about the internals (or > inexistence thereof) of raw devices. How is synchronization with the > buffer cache guaranteed? There is, intentionally, _no_ synchronization with the buffer cache. The primary advantage of raw devices is to allow arbitrarily large single I/O requests to take place (128 kbytes per operation isn't unusual with something like Oracle) directly into the application address space (eliminating an extraneous copy). Raw devices are historically intended to be used stand-alone, in other words, the block device is never used coincidentally with the raw device. This is standard Unix semantics for raw -vs- block devices that has existed since Ken and Dennis started Unix. > > In particular, say that I want to insert an intermediate (e.g. encryption) > layer in between the buffer cache and the device driver; will raw I/O > bypass this (I presume it will). Is there any possibility to prevent this > (say that my hard disk is encrypted and I want to decrypt before any > information is accessed)? The only way to prevent access to data contained on a raw device is to use the existing discretionary access control mechanism (e.g. chmod). Note that even in the absence of raw devices, your encryption layer could be bypassed using the sg driver, or by connecting the media to a different type of unix system. scott > > Thank for any suggestions, > > Erik De Win > ******************************************************************************* > Erik De Win > COSIC research group e-mail: erik.dewin@esat.kuleuven.ac.be > K.U.Leuven voice: +32-(0)-16-32.18.85 > K. Mercierlaan 94 fax: +32-(0)-16-32.19.69 > B-3001 Heverlee www: http://www.esat.kuleuven.ac.be/~dewin/ > ******************************************************************************* > > From owner-rawio@oss.sgi.com Tue Feb 29 05:01:05 2000 Received: by oss.sgi.com id ; Tue, 29 Feb 2000 05:00:56 -0800 Received: from www.mezon.net ([212.108.197.44]:28938 "EHLO szorvor.mezon.net") by oss.sgi.com with ESMTP id ; Tue, 29 Feb 2000 05:00:54 -0800 Received: from localhost (agdolla@localhost) by szorvor.mezon.net (8.9.3/8.9.3) with ESMTP id OAA67416 for ; Tue, 29 Feb 2000 14:00:48 +0100 (CET) (envelope-from agdolla@mezon.net) Date: Tue, 29 Feb 2000 14:00:48 +0100 (CET) From: Gabor Dolla To: rawio@oss.sgi.com Subject: raw device on linux and oracle Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-rawio@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;rawio-outgoing Hi Do you have any info on how to setup Oracle database on a raw device on Linux ?? thanks Gabor