Read the rest of this story if you're interested in seeing MS-DOS formatted FireWire drives on your desktop.
First of all, BE CAREFUL!!! You have the potential of really messing things up. Now, use the OS X Disk Utility (in Applications -> Utilities) to view some information about the disks connected to your computer. There is a mount option in the menu, but presently it only supports UFS, HFS+, and UNIX file systems. But UNIX can mount almost any file system so...
In the OS X Disk Utility, select the desired drive partition. The information tab will give you the MS-DOS partition information, under the heirarchy but it will say it is not mounted. Then, under the First Aid tab, when you click Verify it scans through and says something like:
Verifying disk "Untitled 1"This gives you the UNIX device name and will be used to actually mount the device through UNIX in a few steps.
** /dev/disk1s1
Verify Completed
Make a directory at the root level to make a directory point to mount the drive.
mkdir /msdosdiskThe next step is the magical UNIX step that mounts the MS-DOS drive to the directory that was just made. Make sure that you replace the 'disk1s1' name with the device name you found with the disk utility.
sudo mount_msdos /dev/disk1s1 /msdosdiskNow, in the Finder use command ~ or select "Go to folder" from the menu and type:
/msdosdiskand pop the drive will appear on the desktop! You can go ahead and start copying files.
To unmount the disk you need to drag the disk to the trash. This removes it from Aqua but then you need to also unmount it from Unix with the following command:
sudo umount -f /msdosdiskAs a side note I was also able to format drives for MS-DOS FAT32 using the following command:
sudo newfs_msdos -F 32 /dev/disk1s2[NOTE: BE VERY CAREFUL!! You have the potential of really messing up your system if you wrote in disk1s1 instead of disk1s2. In this case I would have erased my hard drive instead of the desired drive because of one digit!]
I have had no problems with the above code in 10.1.1; however I don't know how this actually works, it just does. By using the sudo command you are messing with the system and void any warranty that that no problems will occur.
I hope this is helpful to some people, there will probably be some easier ways and maybe some GUI method to do it in the future (hopefully Apple will include this in with the GUI of the disk utility in later versions.) If anyone knows an easier way to do this let me know.

