NTFS-3G, a free and open source read/write file system driver for the
Windows file system NTFS. This document will explain what NTFS-3G is, how to install it and use
it, and how to perform certain other operations.
This version of NTFS-3G has been adapted to Mac OS X, and can be used with both PowerPC
Macs and the newer Intel Macs. It requires Mac OS X 10.4 (Tiger) or 10.5 (Leopard), and the free
library MacFUSE in order to work.

Mac OS X has a kind of plugin-based file system interface, where anyone can extend the operating
system with new file system bundles, to make the operating system recognize, mount, create and
repair other file systems than the built in types. This is what this NTFS-3G package uses to glue
together the operating system independent NTFS-3G driver with Mac OS X.
Usually file systems drivers live in the kernel of the operating system, which makes writing them a
risky business as they can easily crash the whole system if the developer makes mistakes. This is
not the case with NTFS-3G. Instead, it lives in “user space”, where all other programs run, and is
linked to the kernel through the file system bridge MacFUSE (a Mac version of FUSE, “Filesystem
in Userspace”, originally created for the Linux kernel).
This approach makes NTFS-3G a lot more portable, and safer, since system stability won't be
affected in the event of a file system driver crash. The only theoretical downside is that CPU usage
will be slightly higher due to increased kernel/user space communication, which can result in
slower read/write speeds. In practice, however, it has been shown that the speed of NTFS-3G can
easily compare with kernel-based drivers (see: http://www.ntfs-3g.org/performance.html).

NTFS-3G for Mac OS X is currently released in two different versions for each new source release,
the stable build and the ublio build. The reason for this is to make it possible for people to choose
between data safety and performance.
NTFS-3G was originally written for Linux, which successfully, and with high performance provides
caching for the hard disk devices that NTFS-3G accesses. Mac OS X and FreeBSD does not have
that kind of efficient caching layer, so something similar must either be provided by NTFS-3G
itself, or not at all. Ublio is the name of the caching layer provided by NTFS-3G through a patch. It
was originally written by Csaba Henk for the FreeBSD port of NTFS-3G.
When only using internal drives, with ATA/SATA connections, you normally won't notice any
difference in performance between the ublio build and the stable build. It is when using USB drives
that the performance boost is most noticeable. When using a USB hard disk the transfer speed of the
ublio build can be up to 20 times the speed of the stable build.