Re: Syscall table AKA hijacking syscalls

From: Libor Vanek
Date: Fri Jan 02 2004 - 14:41:00 EST


Jörn Engel wrote:
On Fri, 2 January 2004 19:58:48 +0100, Libor Vanek wrote:

On Fri, Jan 02, 2004 at 07:04:31PM +0100, Jörn Engel wrote:

On Fri, 2 January 2004 17:59:22 +0100, Libor Vanek wrote:

This is also something (but just a bit) different - I don't need "change notification" but "pre-change notification" ;)

"Vor dem Spiel ist nach dem Spiel" -- Sepp Herberger

Except for exactly two cases, pre-change and post-change and the same,
just off-by-one. So you would need a bootup/mount/whenever special
case now, is that a big problem?

Probably my english is bad but I don't understand what are you trying to say (except the german part ;-))
A bit more about pre/post-change (if this is what are you trying to say) - I need allways pre-change because after file is changed I can no longer get original (pre-change) version of file which I need for snapshot.
If you take a snapshot on every change within your scope, it doesn't
really matter whether you do it before or after the change. Before
change n is just after change n-1. All you have to do is take another
snapshot before the first change, that is the special case.

But this special case in fact means to copy all the data, if wanted to do it 100% working ;-) And I suggest that it wont' go through my exam ;)

Actually, with userspace notification in place, you could even get
this with just cvs. Whenever a file is changed, commit. cvs add on
creation, etc. Yes, it sucks, but implementation simplicity has it's
own beauty and it would only take a few minutes. :)

I've heard about some fs from Microsoft which should have cvs-like behaviour for all the time ("I want this file version from yesterday") - but I haven't had any details (and I suppose performance hit must be big)

--

Libor Vanek




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