From owner-freebsd-hackers Mon Jul 21 17:21:43 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id RAA22200 for hackers-outgoing; Mon, 21 Jul 1997 17:21:43 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.50]) by hub.freebsd.org (8.8.5/8.8.5) with SMTP id RAA22195 for ; Mon, 21 Jul 1997 17:21:39 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id RAA12149; Mon, 21 Jul 1997 17:18:27 -0700 From: Terry Lambert Message-Id: <199707220018.RAA12149@phaeton.artisoft.com> Subject: Re: Compressed FS To: abial@korin.warman.org.pl (Andrzej Bialecki) Date: Mon, 21 Jul 1997 17:18:27 -0700 (MST) Cc: freebsd-hackers@FreeBSD.ORG In-Reply-To: from "Andrzej Bialecki" at Jul 21, 97 12:07:23 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > I'm reading the Heidemann's thesis right now (on stackable FS design). He > mentions that among others they implemented a compression layer. Did > anyone do something similar under FreeBSD? It would be cool to have it, > IMHO. John has sent the compression code (and some cryptographic code) layers to severa people, including myself, with the request that we not redistribute the code without prior permission. The BSD layering is such that the VM issues are, in some cases, hard to overcome (which is why union FS's currently don't work in the main line tree). Any compression (or cryptographic) FS would face similar problems, since it would need to maintain seperate cache data for the uncompressed (or deencrypted) file blocks. Actually, you should check with John: he was working on the union FS code to make it work with the new VM. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.