ROS-Filesystem FAQ

ReactOS uses file system drivers as WinNT does. For that reason it implements the IFS-interface which stands for Installable File System. Therefore it is or will be able to load and use IFS-drivers. The same as WinNT and WinXP also uses. At the time of writing there was still a problem known as the SEH-Problem which prevents ReactOS from using these drivers. But when the SEH-Problem is solved some time, ROS will be able to load even native NTFS-drivers.

Q: Can we impliment the freedos version of the fat32 filesystem?

A: Reactos supports Fat32 for ages. There's no need to implement another one.

Q: Does ReactOS support VFAT and long names?

A: What are short names? OK. ROS natively supports long and unicode filenames. So it's up to the file system driver how it deals with it. The FAT-driver delivered with ReactOS doesn't support VFAT, now.

Q: Why don't you implement ext2/3 but messing around with NTFS?

A: Because NTFS is a major feature which must be supportet at some time. Ext2/3 is of course a topic for us, however there exist already projects whose goal it is to implement ext2/3 for NT. We will utilize these drivers when they got good enough.

Q: Where can I find the Ext2/3-IFS for NT?

You can find it here:
http://uranus.it.swin.edu.au/~jn/linux/ext2ifs.htm, http://sys.xiloo.com/projects/projects.htm#ext2fsd and http://ashedel.chat.ru/ext2fsnt/

Q: Can I help programming installable file system drivers?

A: Yes, there's lots of work to do around IFS-drivers. It's however very hard to program. I like to say that programming dirvers is hard but programming file system dirvers is the king's discipline. If you are a real kernel hacker, come to our maling list and anounce yourself.

Q: Can we use ext2/3 instead of poking around in NTFS

A: Yes, it's up to you, which file system you want to use. For now however neither the ext2/3-IFS nor the our NTFS-IFS is ready to use for read and write. So there's still lots of work to do (especialy the SEH-Problem) and so the only option is the FAT-IFS.

Q: Why do you not make use of the Linux-NTFS project's sources?

A: These sources are rather ok, but as all NFTS implementations (but the one from MS) it lacks writing support. And there are still big areas wich are undocumented. We are working together with them or just using their code. In the moment ther's however not that priority for NTFS.

Q: I would vote for reiserfs as the standard FS for ReacOS

A: Good Idea. However there's no ReiserFS driver for NT/ROS available. You are welcome to program one. I think in the last time there apeared one in the net.

Q: The JFS-sources (also for OS/2) are free to download. Why not make JFS the standard FS in ROS?

A: Yes, at least an IFS is already planned. Since JFS is still a state of the art file system with journalling, big file+partition sizes ACLs and extended attributes and hard links, it would well suite ROS. We are working on it but you are welcome to help.

Q: How do you deal with case sesitivity (i.e. ext2) ?

A: Case sensitivity is not a problem of the file system itself. It's an aspect of the corresponding dirver. The object manager which provides the whole namespace supports case sensitivity natively. So IFS-drivers get a special case flag which they must handle accordingly. A ported file system diriver must therefore be able to handle both, case (in)sensitivity.

Q: Does a 64-bit file system run on a 32-bit machine?

A: Yes. The 64-bit are just the adressing on the disk. It has nothing to do with the executable which contains the driver. That executable hat that manny bits as the whole operating system has.

Q: What file systems does ReactOS support, now?

A: For now, the only file system supported is FAT(12/16/32) without VFAT.

Q: What file systems will ReactOS support?

A: Our goal is to support as many file systems as possible. There can be developed IFS-drivers for at least these disk file systems which are available with linux. It's however verry hard to program a compliand file system driver. So it will take some time.
At least there will be:

Q: I have an idea: Why not throw away these odd drive letters?

A: Old Idea. I'd say that also MS has had this idea. But they didn't realize it up to now. Hmm. In the ROS-team there are also thinkings about this issue. But up to now there has not been a sufficient conclusion about this topic. Maybe MS does this way as well.
There are Ideas as having a memory based mount file system or uncovering the object managers name space to win32-apps or drive words. Everything brings disadvantages with it.
By the way: The ROS/NT-Kernel doesn't work with drive letters. These are a relict of DOS in win32.

Q: What is a Redirector?

Q: What is a file system recognizer?

Q: What is a file system driver, IFS?

Q: What is Journalling?

Q: What is Journalling?

http://sys.xiloo.com/projects/projects.htm#ext2fsd

© Robert Köpferl <>