[ros-dev] FullFAT replacement for Fastfat.sys

[Daniel Reimer]

Aleksey Bragin 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 at videotron.ca <mailto:ionucu at videotron.ca>
>> To: ros-dev at reactos.org <mailto:ros-dev at 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 at worm.me.uk <mailto:james at worm.me.uk>
>>     > To: ros-dev at reactos.org <mailto:ros-dev at 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
>>     <http://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 at worm.me.uk <mailto:james at worm.me.uk>
>>     >
>>     > _______________________________________________
>>     > Ros-dev mailing list
>>     > Ros-dev at reactos.org <mailto:Ros-dev at reactos.org>
>>     > http://www.reactos.org/mailman/listinfo/ros-dev
>>
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>>
>> Best regards,
>> Alex Ionescu
>>
>>
>
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I like the Idea. Journalling is something I always missed on FAT.