From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 5 May 2001 22:46:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 5 May 2001 22:45:53 -0400 Received: from bitmover.com ([207.181.251.162]:21352 "EHLO bitmover.com") by vger.kernel.org with ESMTP id ; Sat, 5 May 2001 22:45:40 -0400 Date: Sat, 5 May 2001 19:45:36 -0700 From: Larry McVoy To: Chris Wedgwood Cc: linux-kernel@vger.kernel.org, BitKeeper Development Source Subject: Re: Wow! Is memory ever cheap! Message-ID: <20010505194536.D14127@work.bitmover.com> Mail-Followup-To: Chris Wedgwood , linux-kernel@vger.kernel.org, BitKeeper Development Source In-Reply-To: <20010505095802.X12431@work.bitmover.com> <20010506142043.B31269@metastasis.f00f.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0pre3i In-Reply-To: <20010506142043.B31269@metastasis.f00f.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 06, 2001 at 02:20:43PM +1200, Chris Wedgwood wrote: > 1.5GB without ECC? Seems like a disater waiting to happen? Is ECC > memory much more expensive? Almost twice as expensive for 512MB dimms. I used to be a die hard ECC fan but that changed since what we do here is BitKeeper and BitKeeper checksums everything. It tells us right away when we have problems (to date it has found bad memory dimms, NFS corruption, and a SPARC/Linux cache aliasing bug). So I've given up in ECC, we don't need it. On the other hand, if your apps don't have built in integrity checks then ECC is pretty much a requirement. By the way, the integrity checks don't need to be complicated, BK uses a horrible 16 bit ignore the overflow checksum to be compat with SCCS and it seems to have caught everything that much more sophisticated and CPU intensive checksums have caught. In other words, anything is much much better than nothing. -- --- Larry McVoy lm at bitmover.com http://www.bitmover.com/lm