This FAQ is part of the
Linux NTFS Project.
The latest version can be found online at
ntfs.html
If you have an NTFS question that isn't answered in this FAQ, or you have comments about the FAQ, please email linux-ntfs-dev@sourceforge.net
- Most frequently asked questions
- Other interesting bits
- Note carefully
| 1.1 What is NTFS? | |
| 1.2 Is NTFS better than FAT/FAT32? | |
| 1.3 Do I have to use NTFS? (Or upgrade?) | |
|
1.4 Is NTFS the same in every version of Windows? |
| 1.5 What are NTFS's limits? |
| 5.1 Can I boot Windows on an NTFS volume? | |
| 5.2 How do I use lilo? | |
| 5.3 How do I use grub? |
| 6.1 Which distributions support NTFS out of the box? | |
| 6.2 Why don't RedHat support NTFS? | |
| 6.3 Why does RedHat Linux lock up when accessing an NTFS Volume? | |
| 6.4 Do any distributions install onto NTFS? |
NTFS is an abbreviation for New Technology Filesystem. NT
because it
was originally used in Windows NT and a filesystem is just how the computer
stores files on disk. Different operating system, stores files in different
ways.
NTFS is used by Windows NT, 2000, XP and Windows Server 2003.
In brief, yes. It's far more robust, it supports Unicode filenames, proper security, compression and encryption. Its main fault is that it can only be read from Windows NT, 2000 or XP, i.e. you can't use a DOS boot disk and then read your data.
As always there are exceptions to this rule. Linux has had a driver for NTFS since December 1997. Also there's a program to give DOS NTFS support (see Section 2.1 for more details).
No, you don't have to, though for most people it is a good idea. You probably won't even notice the difference. The only catch, is that you cannot convert back to FAT (see Section 2.3 for more details).
You can install Windows NT on a FAT16 filesystem and Windows 2000 or XP on
a FAT32 filesystem. Then you can upgrade to NTFS later.
No. They will look similar, but newer versions have extra features. For example, Windows 2000 has quotas.
| NTFS | Windows Version |
|---|---|
| v1.2 | NT 3.51, NT 4 |
| v3.0 | 2000 |
| v3.1 | XP, Server 2003 |
Version 1.2 is sometimes known as 4.0.
Versions 3.0 and 3.1 are sometimes referred to as 5.0 and 5.1.
BIG. NTFS supports files up to 263 bytes in size. NTFS Volumes can be up to 263 clusters and each cluster can be up to 64KiB long. This gives NTFS an upper limit of approximately 500 trillion gigabytes.
Unfortunately, you can't. These versions of Windows can only understand FAT. NTFS can only be read by Windows NT, 2000 and XP.
However, with a little work, you can use a couple of utilities from SysInternals "NTFS for Windows 98" and "NTFSDOS" allow you to read NTFS from Windows 95, 98 and DOS. If you are prepared to pay, they even have versions that will write to NTFS (N.B. It is very expensive).
Open a command window and type (replacing x:
with the correct volume):
convert x: /fs:ntfs
If the volume is in use, the conversion will happen when you next reboot.
The command is not easily reversed. See the next FAQ.
The simple answer is, "You can't". There is an exception if you have money. Partition Magic, available from norton.com can convert between several filesystems, including NTFS and FAT.
This depends on which Operating System you are using.
DOS, Windows 95/98/ME: fdisk. Use a boot disk, or ask Windows to go to DOS mode. Then run fdisk. If you have more than one disk, first select that. Then you want to delete a non-DOS partition. Be very careful, your changes will be committed immediately.
Windows NT: Computer management.
Windows 2000, XP and Server 2003: Logical Disk Manager. Start at the Control Panel, select Administrative Tools, then Computer Management.
After a volume has been in use for a while, after many writes to the disk, the files can end up fragmented. That is not in one consecutive place on the disk, but in many small pieces. This causes a slowdown when trying to access these files.
Windows 2000, XP and Server 2003 have a defragmenting program built in.
For users of Windows NT, there is a free program to do the same job.
Diskeeper Lite
can be downloaded from:
http://diskeeper.com
Use our stable and widely used program, ntfsresize. Or even better, one of the easy-to-use partitioners (DiskDrake, QTParted, YAST, EVMS, Partman, GParted, etc) that integrated it. For more information, please read the ntfsresize FAQ.
The Linux Driver can read all the versions of NTFS. Each version is slightly different, but the driver only has to interpret the files and directories. All the indexes that NTFS maintains can be safely ignored.
When the driver becomes able to write to an NTFS Volume, then it may be that the abilities will vary according to the version of NTFS it is writing to.
Not really, but if you only need to copy files from Linux to Windows on a dual-boot machine, see "How to write to NTFS" below for a possible way to work around the lack of write support. For write support in Linux, read on.
There are two drivers, currently. The original driver, in 2.4 has some write code in it, but it is extremely dangerous to use it. The possibility of destroying your filesystem is very high.
The new driver, introduced in 2.5.11, has some write code, but it's very limited. The driver can overwrite existing files, but it cannot change the length, add new or delete existing files.
Adding write support will take a long time. NTFS is built like a database. Any changes you make, necessitate making changes in many places, for consistency. Make a mistake and the filesystem will be damaged, make too many mistakes and the filesystem will be destroyed. Also, the current developers are only working on NTFS as a hobby, during their free time. If you'd like to help, please email me: linux-ntfs-dev@sourceforge.net
How to write to NTFS. If you are using a dual-boot machine and just need NTFS write support to transfer files from Linux to Windows, you can instead use a Windows driver for ext2/ext3 and, while running Windows, read the files from the Linux partition instead. This way, using two read-only drivers, you can still copy files from one file system type to the other.
We know about these open source Windows drivers for ext2 and ext3 Linux filesystems, as of June 4th, 2003:
NTFS supports a wide range of features, but few are honoured by the Linux NTFS Driver.
The Linux NTFS Driver supports: Unicode filenames (converted into a local codepage, or utf8); compressed files; sparse files.
However, the driver cannot read encrypted files, it ignores Windows' security information and ignores quotas set by Windows.
The driver is pretty safe read-only, but it's impossible to test every eventuality. If something goes wrong, please help us to find the problem and fix it.
Please email the development team at linux-ntfs-dev@lists.sourceforge.net and tell us which version of the driver you are using, which Linux version (uname -a) and which version of NTFS (Win NT, 2K or XP).
Additionally, if there are any logs (/var/log/messages) that you think may be useful, please include them.
Thanks.
Most users won't have to compile anything to enable NTFS support. Almost every Linux distribution (with the notable exception of RedHat) comes with NTFS support out of the box.
If you are using RedHat 9 (Shrike), 8.0 (Psyche) or 7.3 (Valhalla), then you can simply install an rpm for NTFS support. The rpm comes with detailed instructions.
If you have an older version of RedHat, or another distribution which doesn't include NTFS support, then you will have to compile the kernel yourself. This isn't as difficult as it sounds. Have a look at the Compile Page for more details.
The new version of the driver is better. It is better written, much faster, has fewer bugs and is SMP-safe. The new driver is available in 2.5.11 onwards and a patch is available to add the new driver to 2.4 kernels.
At the moment, there are only a few tools and they are aimed at developers. We keep a status list of all our tools.
Naturally the priorities lie in getting NTFS write support coded.
Microsoft haven't released any documention about the internals of NTFS, so we had to reverse engineer the filesystem from scratch. The method was roughly:
If this sounds like a lot of work, then you probably understand how hard the task has been. We now understand pretty much everything about NTFS and we have documented it for the benefit of others: ../ntfs/index.html
Actually writing the driver was far simpler than gathering the information.
First we have to thank Martin von Löwis. He created the original NTFS driver back in 1995. It was added to the Linux Kernel in December 1997 (2.1.74). He has been helped by the following kind souls:
Albert Cahalan, Anton Altaparmakov, Damon Casale, David Dillard, Domagoj Pensa, Joseph Malicki, Matthew Fanto, Olof Wolgast, Rani Assaf, Régis Duchesne, Richard Russon, Steve Dodd, Werner Seiler.
Next we have to thank Anton Altaparmakov, it was his enthusiasm which kept the project alive. At a time when the project was effectively unmaintained, he took over and stabilised the code. He went on to rewrite the driver from scratch in order to have a clean base to progress with write support. He has been helped by:
Pawel Kot, Richard Russon.
Of course. The Driver can read all versions of NTFS, but it is read-only.
When used read-only, both the Original and New Drivers are safe for general use. They will not make any changes to your filesystem, so they cannot cause any damage.
Additionally, the New Driver is SMP-safe.
In Linux disks are named hda, hdb for the first two disk on the first IDE controller and hdc, hdd for the third and fourth disks. SCSI disks are named sda, sdb, etc, in the order they are discovered.
A simple way to look for NTFS Volumes is using:
fdisk -l
The output might look like:
Disk /dev/hda: 64 heads, 63 sectors, 4465 cylinders
Units = cylinders of 4032 * 512 bytes
Device Boot Start End Blocks Id System
/dev/hda1 1 2125 4283968+ 07 NTFS/HPFS
/dev/hda2 2126 19851 35735616 0f Win95 Ext'd (LBA)
/dev/hda5 * 2126 4209 4201312+ 83 Linux
/dev/hda6 4210 4465 516064+ 82 Linux swap
If your kernel version is 2.4.*, or 2.5.0 - 2.5.10, then you probably have the Original NTFS Driver. If you have 2.5.11 or later, then you have got the New NTFS Driver.
A better test is to look through the kernel logs for the NTFS log message. Try either of these commands (you may need to be root to read the logs).
dmesg | grep -i ntfs
grep -i ntfs /var/log/messages
The Original Driver is version 1.1.*, whereas the New Driver is version 2.*.
First of all, it might be an idea to check that your kernel understands
NTFS. The command below will give a list of all the filesystems that Linux
understands. If you see ntfs
, then you are OK. Also it might be a
good idea to read the mount manual, man 8 mount
.
cat /proc/filesystems
Next you need to create a place to mount the NTFS Volume. Then you can mount it.
mkdir /mnt/windows
mount /dev/hda1 /mnt/windows -t ntfs -r
To alter the permissions of the mounted filesystem, see the umask
option in Section 4.6. If you would like to have the
volume mounted automatically at boot time, see
Section 4.10.
When you have finished, you can unmount the partition with either of:
umount /mnt/windows
umount /dev/hda1
The command is called umount
(only one 'n').
These mount options are common to both drivers. It's recommended to also read the man page for mount. The general form of mount is:
mount device directory [options]
Additional options of the for -o option
can be given individually, or
as one parameter separated with commas. These two commands are equivalent:
mount /dev/hda1 /mnt/windows -o X -o Y -o Z
mount /dev/hda1 /mnt/windows -o X,Y,Z
-r.
mount /dev/hda1 /mnt/windows -t ntfs -r -o umask=0222
mount /dev/hda1 /mnt/windows -t ntfs -r -o uid=flatcap
mount /dev/hda1 /mnt/windows -t ntfs -r -o uid=500
mount /dev/hda1 /mnt/windows -t ntfs -r -o gid=winusers
mount /dev/hda1 /mnt/windows -t ntfs -r -o gid=520
To find out which driver you are using, see Section 4.4. This section discusses the options for the Original Driver only. All the common mount options are discussed in Section 4.6.
Several options take a true
or false
parameter.
You may replace true
with yes
or 1
.
You may replace false
with no
or 0
.
NTFS stores all file and directory names in Unicode which can represent any character from any language. By default the Linux NTFS driver converts the names to ASCII which is OK for some people, but no good if your languages includes letters like å or é.
NLS (Native Language Support) controls how characters are displayed. You can choose either utf8 which, like Unicode, can represent all characters, or your own codepage, e.g. iso8859-1 (Western Europe), iso8859-2 (Central Europe), gb2312 (Simplified Chinese), iso8859-8 (Hebrew). Below are some example mount commands:
mount /dev/hda1 /mnt/windows -t ntfs -r -o iocharset=utf8
mount /dev/hda1 /mnt/windows -t ntfs -r -o iocharset=iso8859-2
mount /dev/hda1 /mnt/windows -t ntfs -r -o iocharset=gb2312
If your kernel doesn't support utf8, then you can use this option to
work with utf8 support from the NTFS Driver. You should use
-o iocharset=utf8
wherever possible.
mount /dev/hda1 /mnt/windows -t ntfs -r -o utf8=true
Windows preserves the case of filenames, but it doesn't distinguish when
you read. Therefore you can create a file called MyFileName
and
then open it by asking for mYfILEname
.
By default Linux is case sensitive, MyFile
, MyFile
and
myfile
are all different files. If you would like Linux to
behave like Windows, for an NTFS volume, set the posix
option to true
. Setting the option to false
will make
the driver behave like Linux (the default).
mount /dev/hda1 /mnt/windows -t ntfs -r -o posix=true
If this option is set to true, then the filesystem metadata will be
visible. If the aren't visible, they can still be explicitly listed by
providing their name, e.g. ls -l \$MFT
.
Because of a limitation of glibc, $MFT
may not appear in listings
because it is inode number zero.
mount /dev/hda1 /mnt/windows -t ntfs -r -o show_sys_files=true
To find out which driver you are using, see Section 4.4. This section discusses the options for the New Driver only. All the common mount options are discussed in Section 4.6.
Several options take a true
or false
parameter.
You may replace true
with yes
or 1
.
You may replace false
with no
or 0
.
NTFS stores all file and directory names in Unicode which can represent any character from any language. By default the Linux NTFS driver converts the names to ASCII which is OK for some people, but no good if your languages includes letters like å or é.
NLS (Native Language Support) controls how characters are displayed. You can choose either utf8 which, like Unicode, can represent all characters, or your own codepage, e.g. iso8859-1 (Western Europe), iso8859-2 (Central Europe), gb2312 (Simplified Chinese), iso8859-8 (Hebrew). Below are some example mount commands:
mount /dev/hda1 /mnt/windows -t ntfs -r -o nls=utf8
mount /dev/hda1 /mnt/windows -t ntfs -r -o nls=iso8859-2
mount /dev/hda1 /mnt/windows -t ntfs -r -o nls=gb2312
The umask
parameter alters the permissions of both files and
directories (see Section 4.6 for a reminder).
fmask
works on files and dmask
works on directories in
the same way. The effect of the options can be combined, too. Here are
some examples:
mount /dev/hda1 /mnt/windows -t ntfs -r -o fmask=0222
mount /dev/hda1 /mnt/windows -t ntfs -r -o dmask=0222
mount /dev/hda1 /mnt/windows -t ntfs -r -o fmask=0077,dmask=0222
Windows preserves the case of filenames, but it doesn't distinguish when
you read. Therefore you can create a file called MyFileName
and
then open it by asking for mYfILEname
.
By default Linux is case sensitive, MyFile
, MyFile
and
myfile
are all different files. If you would like Linux to
behave like Windows, for an NTFS volume, set the case_sensitive
option to false
. Setting the option to true
will make
the driver behave like Linux (the default).
mount /dev/hda1 /mnt/windows -t ntfs -r -o case_sensitive=true
mount /dev/hda1 /mnt/windows -t ntfs -r -o case_sensitive=false
By default, the driver will refuse to mount if any of the options are incorrect. By adding the sloppy parameter the driver will simply ignore bad parameters.
mount /dev/hda1 /mnt/windows -t ntfs -r -o sloppy=true
mount /dev/hda1 /mnt/windows -t ntfs -r -o sloppy=false
This option controls how the driver copes with problems. The default is to try and continue. Any corruption will be marked and worked around. The alternative is to get the driver to try and recover. At present the only recovery the driver can do is to replace the boot sector with the backup.
mount /dev/hda1 /mnt/windows -t ntfs -r -o errors=continue
mount /dev/hda1 /mnt/windows -t ntfs -r -o errors=recover
There are three options to control the permissions and ownership of files
and directories. They are: umask
, uid
and gid
. They
are mentioned in Common mount options.
Below are some examples of each option and how it affects the files. We will use the same mount command each time and just show the options.
mount /dev/hda1 /mnt/windows -t ntfs -r
umask
is a filter of permissions, so it works in the opposite way to
chmod. Full permissions are equivalent to 777 (rwxrwxrwx). A umask of 0222
(-w--w--w-) leaves 555 (r-xr-xr-x).
The default umask is set to 0077, for security reasons.
mount ... -o umask=0277
-r-x------ 1 root root 28096 Aug 24 1996 chkdsk.exe
mount ... -o umask=0222
-r-xr-xr-x 1 root root 28096 Aug 24 1996 chkdsk.exe
So far the files still have an owner and group of root
. Next we try
the uid
and gid
options.
mount ... -o uid=flatcap
-r-x------ 1 flatcap root 28096 Aug 24 1996 chkdsk.exe
mount ... -o gid=winuser
-r-x------ 1 root winuser 28096 Aug 24 1996 chkdsk.exe
mount ... -o uid=flatcap,gid=winuser
-r-x------ 1 flatcap winuser 28096 Aug 24 1996 chkdsk.exe
Finally we combine a few options for precise control. Below we allow the
user flatcap
full control, the group of users winuser
has read
permissions and other people have no access at all.
mount ... -o umask=0027,uid=flatcap,gid=winuser
-rwxr-x--- 1 flatcap winuser 28096 Aug 24 1996 chkdsk.exe
Once you are happy with your mount command, you can teach Linux how to mount
the volume automatically by adding a line to /etc/fstab
(filesystem table).
Below are some example mount commands and their equivalent fstab.
Don't worry about the meaning of the 0 0
on the end.
mount /dev/hda1 /mnt/windows -t ntfs -r
/dev/hda1 /mnt/windows ntfs ro 0 0
Here we've transformed -r
into the equivalent -o ro
.
mount /dev/hda1 /mnt/windows -t ntfs -r -o umask=0222
/dev/hda1 /mnt/windows ntfs ro,umask=0222 0 0
mount /dev/hda1 /mnt/windows -t ntfs -r -o umask=0222,uid=flatcap,gid=winuser
/dev/hda1 /mnt/windows ntfs ro,umask=0222,uid=flatcap,gid=winuser 0 0
Yes, both grub and lilo can boot Windows from an NTFS Volume. What actually happens, is that the Linux boot loader finds the NTFS boot loader and gives control to it.
Add this entry to /etc/lilo.conf, then rerun lilo.
other = /dev/hda1
table = /dev/hda
label = Windows
The other
points to the partition containing Windows and table
points to the partition table of the disk.
Add this entry to /boot/grub/grub.conf
title Windows
root (hd0,0)
makeactive
chainloader +1
According to the grub disk numbering, /dev/hda is hd0, hdb is hd1, etc. The partitions are numbered from zero. Therefore, hda1 is hd0,0, hdc4 is hd2,3.
The Linux Distributions that are known to support NTFS are: Mandrake, Debian, SuSE, Gentoo and Caldera
In fact, the pattern is, that if the name isn't RedHat, then they will support NTFS.
I'd really like to know. The rumours are that it's a legal worry.
Check which kernel version you are using with the command uname -a
.
If the version is 2.4.9 then it is important for you to update your kernel.
See the RedHat Website
for more details.
If you'd prefer, you could compile your own kernel. See How do I add NTFS support to Linux? for more details.
Not quite. Phat Linux can install onto a FAT partition within Windows, then boot from the files inside Windows. The New Driver nearly has enough support for them to perform this trick using NTFS.
It is a complete rewrite of the NTFS driver. The original driver was writen over a period of many years. In the beginning we knew little about NTFS or Linux and the source code became hard to maintain.
We created a new driver, with our new knowledge, which is much simpler, faster and easier to maintain.
No. There is already an NTFS driver in the current Linux kernel, so you don't need to use the new driver. The original driver, though old, is reliable enough for everyday use.
We release the new driver as a patch to the official Linux kernel source code.
../downloads.html
http://www.kernel.org/pub/linux/kernel/v2.4/
A patch is a set of changes for a set of text files. Since we are only altering the NTFS code, it is inefficient to release all the kernel code every time we make a small change. We make our patches against official Linux kernel releases.
Once you have unpacked the source, change directory into the source directory and use the command (replacing the path and patchname as necessary):
patch -p1 < path/to/patchname
This will modify the source code. There should be no rejects or failures. Next build the kernel as normal. There are instructions for this elsewhere in this FAQ.
Sorry. We try to help everyone we can, but we have a limited amount of time. There are a few sites that might help you understand the basics about Linux. Alternatively, find out if there is a Linux User Group near you.
There are two kernels to consider. The new code is already in the development Linux Kernel. It was introduced in 2.5.11.
The stable Linux Kernel, currently 2.4.20, still has the old driver. We are happy with the state of the code, but we still have to convince the Kernel Gods that it's good.
Until it is incorporated, we will make frequent releases in patch form.
It sounds like a great idea, to start with, but there are numerous problems.
The largest technical problem is joining the Windows system DLL to the Linux VFS. It could be done, but it wouldn't be pretty. It would have to run as part of the kernel which would mean that if it went wrong it could crash the machine. With no source, we might not be able to work around the problem.
The next major problem is compatability. Which version of the Windows system file would we use? Picking one would limit its use, making the wrapper versatile for all of them would be a programming nightmare.
And it gets worse. The legal implications of distributing Windows systems files would cause problems. Also the proprietary nature of the driver would mean that the other kernel coders would not investigate any problems if someone had used the NTFS wrapper.
Anyway, there has been a brave man that done it. Jan Kratochvil's Captive is such Windows' driver wrapper. It is able to write NTFS files, but is known to have bugs and is much slower then Linux NTFS driver. Captive is based on ReactOS and uses LUFS driver. Probably if amount of work that was put into Captive development was spent on Linux NTFS driver, we'd have reliable and fully open source driver with write support.
| Copyright © flatcap (Richard Russon) |