If you want a disk format that can be read both by a Macintosh and a Windows PC, basically the only option is formatting the drive in FAT32 (sometimes also referred to as 'MS-DOS' format).I didn't look for it, but I very much doubt it and would strongly discourage you from trying it if you are somewhat interested in your files' integrity. At least, it's not possible using the GUI maybe it can be done using diskutil in the Terminal. If you want an NTFS disk, you have to do the formatting on a Windows machine. It is not possible, not even in 10.4.1, to create an NTFS partition or disk.So the user experience is now like with formatting in any other format. I can't remember for sure (although I did it just a few minutes ago), but I think you don't need to do manual unmounting in 10.4.1 any more Disk Utility will do it for you. This hint mentions it is possible with Disk Utiliy, but only after initial unmounting. It is possible to transform a disk with NTFS into a Mac disk with HFS+ format.Writing to NTFS disks still isn't possible all NTFS disks are mounted 'read only.'.See the bottom of this hint if you are interested in what kind of issues I had using 10.3.8 which were resolved in 10.4.1. Reading from NTFS disks seems to be very stable now in 10.4.1+.As I said, several things here may not be big news to some readers, but I am sure at least some people will appreciate an overview, so here we go. Since I have been interested in using disks usable by both Windows and Mac computers and found info in several other hints on this site which, however, are sometimes rather old and have a long comments section which take a while to read and new points spread in between, I thought maybe some people are interested in a short overview on what can currently be done in this area. This has saved me a lot of trouble: It is now possible to reliably read NTFS disks (NT File System, as used by modern Windows versions such as 2000 or XP) under Mac OS X 10.4 (tested under 10.4.1).

Apple mac os x tiger 10.4