From owner-freebsd-fs Mon Aug 26 19:38:06 1996 Return-Path: owner-fs Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id TAA21441 for fs-outgoing; Mon, 26 Aug 1996 19:38:06 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id TAA21409 for ; Mon, 26 Aug 1996 19:38:03 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id TAA23789; Mon, 26 Aug 1996 19:27:11 -0700 From: Terry Lambert Message-Id: <199608270227.TAA23789@phaeton.artisoft.com> Subject: Re: The VIVA file system (fwd) To: sysseh@devetir.qld.gov.au (Stephen Hocking) Date: Mon, 26 Aug 1996 19:27:10 -0700 (MST) Cc: terry@lambert.org, freebsd-fs@freebsd.org, eric@ms.uky.edu In-Reply-To: <199608270042.AAA00727@netfl15a.devetir.qld.gov.au> from "Stephen Hocking" at Aug 27, 96 10:42:44 am X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-fs@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > I must admit that it looked rather similar to the LFS stuff, so the > forwarding of the message was meant to stimulate some discussion of > the merits of both, rather than as urging for people to play "catch up". > I'm getting a little impatient for LFS and was wondering what was > happening. I'm not the one to ask about LFS; it's interesting, but not enough for me to want to hack on it. I think the Lite2 did not integrate it over the vnode locking changes, so it's more than a little work, since it needs that, plus it needs the VM integration (our VM access should be macrotized for a generic VM for porting anyway). It's all quite nasty in there. I'm also led to believe that Keith Bostic is hacking on the Ganger/Patt soft updates code to integrate it into FFS right now. This means that it will only get worse before it gets better; the Ganger/Patt code is FS specific, when implemented per their sample implementation in the online Appendix A of their paper. It does not consider the FS as a directed graph with commutation and association operators to be triggered to resolve node dependencies. This means it is hard to make a generic "soft updates" implementation that can act as the device interface for all file systems across the board. Doing that work is probably not a short term project, but it could be tackled on an FS-by-FS basis if you were clever about it. Still, it's a lot of work. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.