What happens if another OS makes changes, not knowing about the journal?  Does the journal need to be rebuilt (either partially or fully)?  FAT support would mainly be for compatibility with another OS, so it is pretty much certain that another OS would be writing files onto the file system.

Also, are there really any compelling reasons to add a ReactOS-only feature to a file system that later will be supported mainly only for compatibility?

-ShadowFlare

On Thu, Jul 30, 2009 at 2:36 AM, Aleksey Bragin <aleksey@reactos.org> wrote:
I'll explain the FAT journalling part, it's the idea I had for quite a while, and mainly it's just an experimental, fun idea.
So far FAT provides no consistency of neither metadata nor actual data. In order to maintain consistency, the filesystem's integrity has to be verified and fixed at every boot if not clean shutdown is detected.

Now, if we add a special file, let's say our driver knows its placement for sure, and that file doesn't change size and is not movable, we can implement transactional writing of metadata to the FAT directory entries using this file as a journal.
Advantages:
- Compatibility with original FAT drivers (without journalling of course)
- Metadata is always consistent (no need for a checkdisk).
Disadvantages:
- Please name them.

I suppose that's how ext3 was done from ext2. Why making the same from FAT would be a bad idea?

WBR,
Aleksey Bragin.

On Jul 30, 2009, at 1:52 AM, Pierre SCHWEITZER wrote:

Hi,

"I'm still at a loss as to why you are all ignoring the free, open source, FastFAT driver in the Microsoft WDK.". Wasn't it some kind a license problem? EULA, or something like that? The question rose when ARM ninjas imported CDFS driver from the Microsoft WDK. They finally had to remove it. Anyway, that's not exactly the point.

Regarding your initial question, for FSD an important part is missing in ReactOS: FsRTL package. Moreover, you may (or, you will?) have problems using CC package. But, that's a good point in fact. That way, we'll be able to implement/debug the needed functions, with test case.

Finally, I'd like to come back on that idea: "During the conversation we also discussed implementing a special journaling extension to FullFAT via the windows driver.". I've to admit I don't see how it can be a good idea. IF everything goes well, ReactOS will be able to handle two journalised FS: NTFS and ext3. Those are known, and used FS. Why should we create a "super" FAT instead of using those FS? What about compatibilty?
A better idea would to handle exFAT...

Best regards,
P. Schweitzer

From: ionucu@videotron.ca
To: ros-dev@reactos.org
Date: Wed, 29 Jul 2009 14:00:08 -0700
Subject: Re: [ros-dev] FullFAT replacement for Fastfat.sys

I'm still at a loss as to why you are all ignoring the free, open source, FastFAT driver in the Microsoft WDK.

On 29-Jul-09, at 10:56 AM, Gabriel ilardi wrote:

Hi James,

Welcome to the team!
ReactOS kernel aims to be compatible with W2k3's, meanwhile Win32 subsystem aims atm Vista.
You'll come across missing stuff, just search for UNIMPLEMENTED throughout the code. Encoded started a page with missing functionality here:http://www.reactos.org/wiki/Missing_ReactOS_Functionality 
Hope you have fun with ReactOS as much as we do...

Gabriel ilardi.

> Date: Wed, 29 Jul 2009 13:59:42 +0200
> From: james@worm.me.uk
> To: ros-dev@reactos.org
> Subject: [ros-dev] FullFAT replacement for Fastfat.sys
> 
> Hi Everyone,
> 
> I just thought I'd introduce myself. I am the author of a new FAT
> implementation that was really designed for embedded systems. As such
> it provides very good performance. (See www.fullfat-fs.co.uk).
> 
> Fireball contacted me a few days ago to discuss the current
> development of FullFAT, and since I have agreed to implement an IFS
> driver based on FullFAT with a view to replacing the current
> fastfat.sys implementation. During the conversation we also discussed
> implementing a special journaling extension to FullFAT via the windows
> driver.
> 
> I hope to start work on this project in the next few weeks, and
> further to this I would also like to help in some other areas of
> ReactOS. I shall be taking a closer look at the ReactOS code over the
> coming weeks, and will probably post some questions about various
> aspects. I have just bought the Windows Internals, fifth edition
> co-authored by Alex Ionescu, hopefully this will provide me with a
> good overview of the Windows architecture etc.
> 
> For complete Windows XP compatibility, just how much of the
> implementation is currently missing from ReactOS?
> 
> Nice to meet you all, and I hope to provide some good contributions to
> ReactOS in the near future.
> 
> James
> 
> --
> James Walmsley
> ----------------------------------------
> james@worm.me.uk
> 
> _______________________________________________
> Ros-dev mailing list
> Ros-dev@reactos.org
> http://www.reactos.org/mailman/listinfo/ros-dev

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