Re: Yet another linux filesytem: with version control

From: Jerome de Vivie (
Date: Mon Jul 23 2001 - 17:00:53 EST

Larry McVoy a écrit :

> Having been through this a time or two, a few points to consider:
> a) This is a hard area to get right. I've done it twice, I told Linus that
> I could do it the second time in 6 months, and that was 3 years ago and
> we're up to 6 full time people working on this. Your mileage may vary.

Yeah, i'm not alone !

I absolutely don't know how much work it is. Will you work again on this
topic ?
You + Me + 5 persons which work with you = 7p

If we need 50p, there is place enought for 43 volunters !

> b) Filesystem support for SCM is really a flawed approach. No matter how
> much you hate all SCM systems out there, shoving the problem into the
> kernel isn't the answer. All that means is that you have an ongoing

A filesystem seems to be the best location to store files. My first
was to get ride of additional layers and, being able to use all UNIX
directly on data. As i say, i have only one idea in head: "do it simple"

> battle to keep your VFS up to date with the kernel. Ask Rational
> how much fun that is...
> c) If you have to do a file system, may I suggest that you clone the SunOS
> 4.x TFS (translucent file system)? It's a useful model, you "stack" a
> directory on top of a directory and you can see through to the underlying
> directory. When you write to a file, the file is copied forward to the
> top directory. So a hack attack is
> mount -t TFS my_linux /usr/src/linux
> cd my_linux
> hack hack hack
> ... many hours later
> cd ..
> umount my_linux
> find . -type f -print # this is your list of modified files
> It's a cool thing but only semi needed - most serious programmers already
> know how to do the same thing with hard links.

I've yet done this kind of solution:
-copy every directories and sub-dircetories of v1/ into v2/
-create a symlink from v2 to v1 for each files.
-protect v1/

To work on a file, we just break and copy the link. But, i don't see how
work with 2 versions of the same file with hard link.

> More brains are better than less brains, so welcome to the SCM mess...

Ya, it's a true mess !


Jerome de Vivie 	jerome . de - vivie @ wanadoo . fr
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