Reformat an NTFS disk to FAT32?

[michael miller]

When I was setting up this computer to dual boot Win XP and FC8 I
initially thought that I would have to convert the hard drive with my
win xp files from ntfs to fat32 in order to have them accessible both to
linux and win xp.  I quickly found out that fc8 has no trouble reading
and writing ntfs files so I just left that hard drive alone.  The "linux
only" hard drives are formated for ext3.

Mike Miller
On Sun, 2008-04-20 at 15:42 -0400, Bruce Labitt wrote:
> Ben Scott wrote:
> > On Sun, Apr 20, 2008 at 11:11 AM, Bruce Labitt <bruce.labitt at verizon.net> wrote:
> >   
> >> I've looked around for this and I see a way or two to do this.
> >>     
> >
> >   As usual, I'm going to ask: Why are you doing this?  What are you
> > trying to accomplish?  :-)
> >
> >   
> Now that I think about this, all that I want is a format that I can read 
> and write to for the WinXP machines that I have to live with and with 
> linux.  The disk does not need to be bootable from XP.  Unfortunately 
> when I received the disk it already was preformatted NTFS.  I don't have 
> any ntfs tools on my old distro.  (I want the disk so I can store  stuff 
> so I can migrate to a home copy of Scientific Linux.)  I just want to 
> have FAT32 on it so I can somewhat indiscriminately use the disk for 
> both linux and windoze.
> >>  One could use mkdosfs, but the documentation indicates that
> >> the disk won't be bootable.
> >>     
> >
> >   Any FAT filesystem created by mkdosfs won't be bootable, because all
> > mkdosfs does is create a filesystem.  It doesn't install an operating
> > system.
> >
> >   What OS are you looking to boot from the FAT partition?  Or are you?
> >   
> Nope - don't really need to.
> >   Generally speaking, if you're looking to install a bootable OS, I
> > recommend using the tools native to that OS to do so.
> >
> >   In the world of Microsoft, to install a bootable MS-DOS, you boot
> > from floppy or CD.  You use FDISK to create the partition, then
> > rebooted (still from floppy/CD) (DOS only checked the partition table
> > at boot).  Then you ran "SYS C:" (where "C:" is the partition you just
> > created).  That installed a boot loader and copied the DOS sustems
> > files (IO.SYS and MSDOS.SYS) to the proper places, along with the
> > shell (COMMAND.COM).
> >
> >   Windows NT and descendants generally require you to run the
> > full-blown GUI "SETUP" routine.  The OS is too complicated; there's no
> > trivial install possible.
> >
> >   Windows 3.x/95/98/ME load on top of DOS, and aren't really magic
> > beyond that, but getting a working install going in the first place
> > still needs the "SETUP" routine.
> >
> >   
> >>  I think it should be possible in fdisk ...
> >>     
> >
> >   fdisk only works with partitions, not filesystems.
> >
> >   You might want to use a more sophisticated tool, like qtparted or
> > gparted or even parted (command line), which handles more of this
> > stuff for you.  If you'd rather know the gory details:
> >
> >   Generally speaking, creating a mountable filesystem is a two-step process.
> >
> >   First, you create a partition for the filesystem to live in.  A
> > partition designates a "slice" of the disk for some particular task
> > (like holding a filesystem).  Each partition has a type code which
> > helps the OS identify what's supposed to be in the partition.  That's
> > the type you're seeing in fdisk.  Setting the partition type doesn't
> > do anything other than change the "type" field in the partition table;
> > it's up to other things to make the contents of the partition actually
> > match the type.
> >
> >   Step two is create the filesystem in the partition.  A filesystem
> > contains all the housekeeping information to keep track of files,
> > directories, permissions, last-modified-time, free space, and so on.
> > Under *nix, one generally uses the some kind of "mkfs" tool to do
> > this.  (In the Microsoft world, one uses "FORMAT" for all the
> > Microsoft filesystems.)  "mke2fs" creates Linux EXT2 and EXT3
> > filesystems.  "mkdosfs" creates FAT and FAT32 filesystems.  "mkswap"
> > marks a swap partition (which isn't technically a filesystem, but
> > serves the same purpose for this discussion).
> >   
> I don't want a multiple partitions, just a single FAT32...  So from your 
> description above I'd change the partition to "c" FAT32 LBA.  And then 
> mkdosfs -F 32 ...
> >   If the partition type doesn't match the filesystem you actually
> > write to the partition, things may actually still work, depending on
> > the OS, the tools you're using, and what you wrote there.  For
> > example, the ext2 and ext3 drivers in the kernel don't care what the
> > partition table says; they look for a signature in the superblock.
> > But tools which look for ext2/3 filesystems to mount for you may only
> > look at the partition table.  Microsoft's OSes generally require the
> > partition table to be correct, or Bad Things happen.
> >
> >   
> >>  I'm sure which of the million format options available is "FAT32".
> >>     
> >
> >   There are several partition types for FAT32; which one to use
> > depends on the disk geometry.  If the disk is big enough that it can
> > no longer use CHS (cylinder, head, sector) to address disk blocks, and
> > instead *must* use LBA (linear block addressing), FAT partitions get
> > different type codes.  (Why?  Because MS-DOS, which Windows 98/ME
> > still boot from, couldn't figure it out without help.)
> >
> >   You have to use the LBA types for partitions located above the
> > roughly 8 GB limit of the classic INT13 BIOS interface.  Partitions
> > which exist entirely below the 8 GB line use the non-LBA type.  (I
> > think.  It's been a long time.)
> >
> >   According to my fdisk, the non-LBA FAT32 is type 0x0B, while the LBA
> > FAT32 is 0x0C (don't enter the "0x" prefix when working in fdisk).
> >
> >   
> My eyes must have glazed over when I saw all the W95 options - they all 
> looked the same.  So c looks like the "right" one.  (For "W95 FAT32 
> (LBA)). 
> 
> So what are options 1b and 1c ???
> 
> >   To get an idea of just what a mess this is, you can see the list of
> > the approximately 15 different "size barriers" here:
> >
> > http://www.storagereview.com/guide2000/ref/hdd/bios/size.html
> >
> > -- Ben
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> >   
> 
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