Although the vast majority of my technical expertise has to do with Microsoft server products, I know plenty of people who operate heterogeneous or even non-Windows networks.
Now that some Mac computers have Intel processors, it is possible to run Windows on them. Some folks might choose to set up their Macs to dual-boot between Windows and OS X version 10.5, also known as Leopard. While this will generally work well, there is one particular issue to be aware of.
Since the hard disk volume being used by Windows is formatted as NTFS, it's important to remember that while OS X can read NTFS volumes, it cannot write to them. This means that you can't use OS X applications to update documents that are stored on the Windows volume unless those documents are saved to an alternate location.
To the best of my knowledge, Mac OS X does not have any mechanisms that can be used to enable full read/write access to an NTFS volume. You can, however, use a third-party utility called NTFS-3G to circumvent this issue.
NTFS-3G is an open source, cross-platform utility that is licensed under the GNU General Public License. Normally, when you hear the terms "open source", "cross-platform", and "GNU" tossed around, the application in question is designed to run on Linux, and NTFS-3G is no exception. Although there is a Mac version of NTFS-3G, there are also versions designed to run on FreeBSD, NetBSD, Haiku, Linux and Solaris.
NTFS-3G has been around for a while, and seems to be fairly popular within the Linux community. Still, I had some initial concerns about things like security, performance and compatibility.
While it seems that most of the major compatibility issues with NTFS-3G have already been corrected, there are still a few things to be aware of. For example, Windows supports automatic compression of files on NTFS volumes. NTFS-3G can read compressed files, but it cannot write to them. Therefore, I would recommend that you disable NTFS compression on the volume before using NTFS-3G.
Another minor quirk that's worth mentioning is that NTFS-3G uses the POSIX namespace, which usually means that filenames are case sensitive. This may confuse some Windows users since filenames usually aren't case sensitive in Windows environments.
As most administrators know, NTFS assigns an owner to every file. Each file has its own Access Control List (ACL) that tells Windows who is and isn't allowed to use the file, and what type of access (if any) is allowed.
I have to admit that I am not sure how ownership information and ACLs are used in the Mac version of NTFS-3G. I can tell you that Linux, for the most part, is able use the various NTFS security attributes.
Both Windows and Linux use the concept of file ownership, so the file's owner is acknowledged by Linux. When it comes to the ACL though, things become a little bit sketchy.
Windows and Linux do not use the same set of rights, and Windows rights tend to be more general than those used by Linux. As such, Linux makes use of the ACL information, but the rights are not always applied in the way you might expect because Linux can't use the rights in their native form. The best that it can do is to try to determine the intent of those rights, and then enforce that perceived intent using its own security mechanisms.
NTFS-3G isn't perfect. It can be CPU intensive, and security tends to be a bit dubious. Even so, it is important to remember that NTFS 3-G is free, and that it may be the only way for you to gain write access to an NTFS volume from a non-Windows operating system.
The creators of NTFS-3G also have a history of improving the utility with each new version, so I think it's safe to say that NTFS-3G is going to get better as time goes on. In the meantime, I would avoid using it on any system on which performance or security is considered critical.
ABOUT THE AUTHOR
Brien M. Posey, MCSE, has received Microsoft's Most Valuable Professional Award four times for his work with Windows Server, IIS and Exchange Server. He has served as CIO for a nationwide chain of hospitals and healthcare facilities, and was once a network administrator for Fort Knox. You can visit his personal Web site at www.brienposey.com.
This was first published in June 2009