Date: Fri, 5 Nov 1999 09:59:56 -0500 (EST) From: Robert Watson <robert@cyrus.watson.org> To: Jan Pechanec <pechy@hp735.cvut.cz> Cc: Erez Zadok <ezk@cs.columbia.edu>, freebsd-fs@FreeBSD.ORG Subject: Re: stupidfs - easily extensible test file systems? Message-ID: <Pine.BSF.3.96.991105095504.51562B-100000@fledge.watson.org> In-Reply-To: <Pine.SGI.4.05.9911051518180.10246-100000@akat.civ.cvut.cz>
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On Fri, 5 Nov 1999, Jan Pechanec wrote: > On Thu, 28 Oct 1999, Erez Zadok wrote: > > Hi, > > I think that it is a bit different. What Robert is hacking is > a filesystem where in-vfs-not-experienced programmer can see how vfs > is working. I have just read some of your papers, Erez, and I think > that wrapfs wants me not to bother with something like vfs (just > encode and decode routines). > > I think that Robert's effort is very useful, I wanted myself > to write somethink like this (purpose: to learn and _touch_ vfs > interface). Robert, do you carry on or not? > > BTW, don't you know why deadfs was written? No doc in FreeBSD. > From what I saw in the source code, operations just fail. Because wrapfs doesn't work in 3.3-RELEASE yet, and because of the reasons you mention, I decided to keep working on a stupidfs :-). That is, that I don't want to add functionality to an existing file system by stacking, but rather to have a new simple file system that I can modify the semantics of in ways not encouarged by the stacking of file systems. I am currently traveling (IETF next week, Active Network conference in Alberquerque the week after) so won't get back to my development machines for about two weeks. After that time, I hope to get a stupidfs implementation to the point where it might be useful for others to see, so I'll put it online. As I mentioned before, the goal is to have a really simple file system with no backing store, appropriate for use when experimenting with new VOPs, etc, etc. It won't be fully functioning (for example, I probably won't even bother to implement symlinks) but it will be *simple*, meaning it can be modifed easily. It will also be separable into an entirely separate module, unlike UFS which has fingers everywhere, so it can easily be loaded and unloaded on demand during development. I wouldn't encourage anyone to use it in production--it will make a fair amount of use of kernel memory, as it won't back to a process--but for development it should be useful. Robert N M Watson robert@fledge.watson.org http://www.watson.org/~robert/ PGP key fingerprint: AF B5 5F FF A6 4A 79 37 ED 5F 55 E9 58 04 6A B1 TIS Labs at Network Associates, Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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