Linux does not actually use FAT or NTFS files systems, but can read and write to them. Linux uses several file systems, mainly ext2,ext3, reiser and a few others. AFAIK Ubuntu uses the ext3. Windows cannot read, write or access Linux files systems (without third party sftwr), so..... that's why we leave an unused FAT partition so that Linux can WRITE to the FAT and then Windows can read those personal files off this partition.
The Ubuntu installer should be able to take care of reformatting any partitions so don't worry about changing anything to FAT or whether Linux can handle it. What you DO have to worry about is to map out what YOU are calling "D" partition to what Linux is calling hdax, where x is any of the partitions that was NOT used by Windows. You must be careful NOT to select "erase and use entire disk" or " resize Windows partition". You should only have to select either of the two UNUSED
NTFS partitions upon which to install at which time the Linux installer will create three partitions WITHIN that partition that you previously made. It is these three NEWLY MADE partitions that you will assign as / (known as the root directory....where the OS goes), a swap partition, and /home ( where your personal files will go). Just a quick note...your external HD will probably be recognized as hdb 1,2,3 etc.
If you are going to use a common FAT partition to exchange files, I would install Linux to the last partition so that the common FAT partition is physically between the two OS's for faster access. (that's my understanding anyway)
If you use the LiveCd, this will not be an issue, however if you install to the HD then there should come a point in the installation where you can review the partitions detected by Linux BEFORE you install. I don't use Ubuntu so I am not familiar with the specifics of their installer, but if memory serves, the installer will come to a screen that shows the partitions. My guess is that partition D will correspond to hda2 as it does in my dual boot with Wxp (NTFS) on hda1, a FAT partition on hda2, and Mandriva on hda5,6,7.
Notice the Windows XP install on hda1 and the blank FAT partition on hda2 in orange.
Notice the Mandriva installation on hda5,6,7 in blue./dev/hda5 / ext3 noatime 1 1
/dev/hda7 /home ext3 noatime 1 2
/dev/hdd /mnt/cdrom2 auto umask=0,user,iocharset=iso8859-1,codepage=850,noauto,ro,exec,users 0 0
none /mnt/floppy supermount dev=/dev/fd0,fs=ext2:vfat,--,umask=0,iocharset=iso8859-1,sync,codepage=850 0 0/dev/hda1 /mnt/win_c ntfs umask=0,nls=iso8859-1,ro 0 0/dev/hda2 /mnt/win_d vfat umask=0,iocharset=iso8859-1,codepage=850 0 0
none /proc proc defaults 0 0
none /proc/bus/usb usbfs auto,devmode=0666 0 0/dev/hda6 swap swap defaults 0 0
/dev/hdc /mnt/cdrom auto umask=0,user,iocharset=iso8859-1,sync,codepage=850,noauto,ro,exec,users 0 0
As far as the root and home partitions, yes Linux likes to keep the users data separate from the OS so if you have to reinstall the OS, you haven't touched your personal data, but this is generally done automatically by the installer. I don't think you should worry so much about installing to "D". Rather you should install to a partition that is indeed free and large enough to accomodate the Ubuntu install. If you can post a description of your partitions AS THE LINUX INSTALLER sees them, not what the Windows OS tells you, maybe we can help.
Again, let me remind you that a LiveCD will allow you to tinker a bit WITHOUT touching your HD.
Hope this helps
UPDATE: oops, yes if you want a common FAT partition then go ahead and convert one of your NTFS to FAT. I think the Ubuntu installer can do that as well. The other NTFS part will be converted automatically to ext3 by the installer.
Edited by Trio3b, 27 August 2008 - 12:30 AM.