largest valid size for FAT32 FS?

[R. C. White]

Hi, Kevin.

Since everybody else chimed in, here's my slant on this subject...

Creating a partition, Formatting a partition, and Using a partition are
actually 3 different topics.

Win2K/XP can CREATE a very large partition. So can MS-DOS, using FDISK.
(So can non-Microsoft operating systems, such as Linux, but I've never used
one of those.) But none of them "create a FAT32 partition" or "create an
NTFS partition". They just "create A partition", which can then be
formatted.

We choose the format for the partition when we FORMAT it, not when we create
it. If we choose to format it FAT32, then it becomes a FAT32 partition. As
others have pointed out, Win98 can format a partition as large as about 128
GB as FAT32. Microsoft has limited Win2K/XP's ability to format FAT32 to
partitions no larger than 32 GB.

WinXP can USE a very large partition. It can use the largest FAT32
partition you can find. It can't format a 100 GB partition as FAT32, but it
can use a 100 GB partition that you've formatted as FAT32 in Win9x/ME, for
example.

Because we seldom create a partition and leave it unformatted, we tend to
think of the create/format process as "creating a FAT32 partition",
overlooking the fact that we've actually done two steps, not just one. If
we choose, we can reformat that "FAT32 partition" as NTFS without deleting
the partition and recreating it.

We often hear that WinXP "can't create a FAT32 partition larger than 32 GB".
That's not exactly correct, but it's easier to say than WinXP can't format
as FAT32 a partition larger than 32 GB".

Of course, we should be saying "volume" rather than "partition", because all
this applies both to a primary partition and to a logical drive in an
extended partition - but not to the extended partition itself.

And, yes, the error message should appear at the beginning, not the end, of
the doomed-to-failure formatting attempt! :>(

RC

 

[Never anonymous Bud]

People do all sorts of things for reasons that *I* don't consider valid. My
point was that*I* don't know of any other reason I consider valid besides
the dual-boot solution I mentioned.

I have my system and several other HDs on FAT32 partitions,
for easier recovery if there is a problem.

I have several NTFS formatted HDs, for DVD and other large files.

I don't think I'm THAT unusual.


Lumber Cartel (tinlc) #2063. Spam this account at your own risk.

This sig censored by the Office of Home and Land Insecurity...

Remove XYZ to email me

 

[Ken Blake, MVP]

Win2K/XP can CREATE a very large partition. So can MS-DOS, using
FDISK. (So can non-Microsoft operating systems, such as Linux, but
I've never used one of those.) But none of them "create a FAT32
partition" or "create an NTFS partition". They just "create A
partition", which can then be formatted.

We choose the format for the partition when we FORMAT it, not when we
create it. If we choose to format it FAT32, then it becomes a FAT32
partition.

Sorry, RC, this isn't correct. File systems are created when you create the
partition, not when you format it. Back in the DOS/Winodws 9x days, you
created the partition with FDISK, choosing the file system there, then
FORMATted it.

With Windows XP, the FDISK/format distinction has been obscured, because
it's now done as a single step which we call "formatting," but the file
system is still chosen when you create the partition.

 

[R. C. White]

Hi, Ken.

Sorry, Ken, but you need to have another look at Disk Management. ;^}

it's now done as a single step which we call "formatting," but the file
system is still chosen when you create the partition.

Nope. We can elect to do both steps in one fell swoop, or we can choose to
create the volume and leave it unformatted.

I'm running Vista at the moment, and this part of DM looks different, but
the end result is the same.

When I right-click on the graphic for an unformatted area (labeled "Free
Space" if it is within the extended partition or "Unallocated" if it is not
inside an existing partition), the context menu offers several choices; the
first is New Simple Volume... Clicking here pops up the "New Simple Volume
Wizard". A few "Next" clicks get me to the "Format Partition" screen. This
screen offers to format it NTFS, FAT, etc., but the top radio button says,
"Do not format this volume". I was startled a year or so ago when someone
in a NG pointed out that DM also offers "Do not assign a drive letter or
drive path". In my experience, there's no way to use the volume until it
has been assigned a letter and formatted, but DM does offer those options.

It is entirely possible to create a volume and leave it unformatted. Until
tomorrow or next year or whenever. It does not become a FAT32 volume
unless and until you choose that file system and format it. And you can
later use DM to reformat that "FAT32 volume" to NTFS without deleting it and
re-creating it as an "NTFS volume".

You are right, of course, that the distinction was obvious in MS-DOS when
FDISK.exe and Format.exe were separate programs. Let's see, didn't we have
to reboot after FDISK before we could run Format?

RC

 

[Ken Blake, MVP]

Hi, Ken.

Sorry, Ken, but you need to have another look at Disk Management. ;^}


Nope. We can elect to do both steps in one fell swoop, or we can
choose to create the volume and leave it unformatted.

I'm running Vista at the moment, and this part of DM looks different,
but the end result is the same.

When I right-click on the graphic for an unformatted area (labeled
"Free Space" if it is within the extended partition or "Unallocated"
if it is not inside an existing partition), the context menu offers
several choices; the first is New Simple Volume... Clicking here
pops up the "New Simple Volume Wizard". A few "Next" clicks get me
to the "Format Partition" screen. This screen offers to format it
NTFS, FAT, etc., but the top radio button says, "Do not format this
volume". I was startled a year or so ago when someone in a NG
pointed out that DM also offers "Do not assign a drive letter or
drive path". In my experience, there's no way to use the volume
until it has been assigned a letter and formatted, but DM does offer
those options.
It is entirely possible to create a volume and leave it unformatted. Until
tomorrow or next year or whenever. It does not become a FAT32
volume unless and until you choose that file system and format it. And you
can later use DM to reformat that "FAT32 volume" to NTFS
without deleting it and re-creating it as an "NTFS volume".

I don't have any unallocated space on any of my machines, so it's difficult
for me to check right now. I'll have to take your word for it.

You are right, of course, that the distinction was obvious in MS-DOS
when FDISK.exe and Format.exe were separate programs.

That's the main point I was trying to make--that in XP those functions which
used to be separate are now united.

Let's see,
didn't we have to reboot after FDISK before we could run Format?

I can't remember for sure, but I don't think so.

 

[R. C. White]

Hi, Ken.

I don't have any unallocated space on any of my machines, so it's
difficult for me to check right now. I'll have to take your word for it.

Just for fun, pick one of your NTFS volumes and reformat it FAT32. ;^]

I'm joking, of course! But you can "go through the motions" and quit before
the actual formatting begins, just to see that, yes, you can change from
NTFS to FAT - or vice versa - without deleting and recreating the volume.
Which proves my point that creating a volume and formatting a volume
(creating the file system on it) are still separate operations.

RC

 

[Guest]

Re: Ken Blake 20 Feb 06 message.

My thanx also to the other parties at this thread (ex: R.C. White, Anna,
others) whose equally as enlightening comments I just read.

OK. Roger on that, Ken. Was talking to myself, trying to figure out what's
going on. Had tried make contact w/ that party. Am in a bit of a situation.
In Thailand at v. busy friend's place. Always out. Systems I saw manned by v.
busy people who speak only few words English. Thought best not make waves.
Check the net first. Primarily just trying to satisfy my curiosity.

In meanwhile, aside from the various possibilities mentioned by all 3 of you
and others (including the allusions to my own just-arrived-at deduction,
which follows), and subsequent to checking Ken's links, I'm thinking it's
quite likely that whoever did it, did so with method in his/her madness; that
is, from their experience, they may have thought ahead and prepared that 2nd
(NTFS) partition to optionally store some really HUGE FILES files - although
from what I know, there's no such thing currently being contemplated around
here. In any case, if I ever get to talk to the man (via a translator of
course), I'll finally know for sure.

In meantime, thanx again, all, for all your time and trouble. I've learned
quite a bit from the broad range of comments here.

P.S.: From my now decrepit "Mastering DOS 6.2", 1994, (Judd Robbins), after
FDISK is done, it

"will prompt you with the following message:

System will now restart

Insert DOS system diskette in drive A:
Press any key when ready

[the more violent "strike any key when ready", I think, came later - Ted...]

Since you just created the partition(s), there is nothing on the hard disk.
Consequently, the system must be rebooted from a previously prepared
system diskette, or . . . . You can now format the entire hard disk as a
system disk, just as you might do to a floppy disk."

Kap koon mak, as they say hereabouts,

--
Ted...

You're welcome. Glad to help.

As for Q2, this is getting to be a bit of a mystery. Since yesterday,

 

[Antoine Leca]

En Plato va escriure:

At least 180 gig if doing with dos fdisk.

How do you get THAT number?

There is a limit around 64 GiB caused by a (display) bug in shipped
fdisk.exe, so at the very least you'll need 263044xxx8.exe update.

However, if you go upwards, I do not believe you'll limited at 180 GB. I see
how you can be limited at 127 GiB (16Mi FAT), then 128 GiB/137 GB (LBA48),
then perhaps around 539 GB (because cylinder rounding will exceed 65,536),
then of course 2048 GiB; but nothing on my board around 180 GB.


Antoine

 

[Antoine Leca]

En news:[email protected], Ken Blake, MVP va escriure:

FAT32 partitions can go up to 2048GB (2TB).

If I am reading correctly what have been published on that subject, you can
have sectors bigger than 512 bytes (offset 11 in the BPB), so this could
lead potentially to file system bigger than 2048 GiB.

Surely such a file system would put OS and support tools under pressure; for
example, no chance for such a big partition to be shoehorsed inside the MBR
table, and probably few if any OS out there would be able to successfully
boot from such a partition ;-). But according to the specs, it appears
possible.


Or am I missing something in your point?


Antoine

 

[Antoine Leca]

I agree with your general standing. On a fine point, though:

En news:[email protected], R. C. White va escriure:

You are right, of course, that the distinction was obvious in MS-DOS
when FDISK.exe and Format.exe were separate programs.

Not so obvious to me.
I noticed that FDISK did some weird things inside the boot record of the
newly created partition, which then would give FORMAT some behaviour; if you
changed (using different tools) the bytes inside the boot record, FORMAT
could then have different behaviour (I did that successfully to get
not-standard cluster sizes, for example; you could also create bigger FATs,
IIRC); if you wiped the whole partition then FORMATed it, you could very
well end with a different result than using the standard procedure, too.

Let's see,
didn't we have to reboot after FDISK before we could run Format?

Sure: the partition table is remembered by the OS as the order of the
letters, and FDISK altered this. Since this order is determined at each boot
(no persistancy here), you're required to re-enumerate, just to be able to
run FORMAT (which needs a letter).

There could have been a way to do that using Int 2Fh AX=0801, though; I
guess IBM/MS programmers were not at ease to let such interface (designed
for CONFIG.SYS time) to be used later.


You should remember that FORMAT comes from MS-DOS v.1 and the support for
any (FAT) volume, while FDISK is initially a IBM tool specific to the PC
architecture (the MBR, introduced with PC/XT and PC-DOS 2.00); by the way,
Int2F/0801 (DRIVER.SYS) appeared only with DOS 3.20, IIRC.


Antoine

 

[Ken Blake, MVP]

En Ken Blake, MVP va
escriure:

If I am reading correctly what have been published on that subject,
you can have sectors bigger than 512 bytes (offset 11 in the BPB), so
this could lead potentially to file system bigger than 2048 GiB.

I'm not aware of any way to change the standard sector size. If there is
one, the risk of doing so breaking all sorts of other programs would
probably be very great. I wouldn't want to try it and find out

 

[Antoine Leca]

En Never anonymous Bud va escriure:

I have my system and several other HDs on FAT32 partitions,
for easier recovery if there is a problem.

It is now really time to learn how to use WinPE/BartPE for such uses. FAT
for recovery use (only) will become pretty old-fashionned in the near
future. Just consider how unpractical it becomes when you have a 64-bit
setup (standard for servers in very few years from now.)

Also, if I did full hand-reparation of a FAT16 volume (cluster by cluster,
that is), I never succeed at such aim with FAT32, unless of course the
volume was empty or almost.
"Easy recovery" as we knew is thing of the past, mostly.

I don't think I'm THAT unusual.

Nowadays, I agree with you.
However, world is walking on while you type...



Antoine

 

[Antoine Leca]

En news:[email protected], Ken Blake va escriure:

I'm not aware of any way to change the standard sector size.

Just put 1024 or 2048 where there is nowadays written 512, and you are done.
Of course, you probably need as well to have a disk driver/stack that knows
how to translate such sectors into the (several) hardware ones. I remember
reading the Linux VFAT driver long ago, and I believe it was able to do
that. I did not try with the NT or 9x ones from Microsoft, but I would not
be surprised if it indeed works... more or less, that is, just to read a
directory or a file.

If there is one, the risk of doing so breaking all sorts of other
programs would probably be very great.

Sure. However, I consider these programs to be somewhat brocken.

Sometimes, they are "brocken" for clear and acknowledged reasons (like the
16 MiB limit on the FAT size hence 128 GiB volumes); sometimes it is
sloppiness (like the 64 GiB bug for 9x FDisk); and sometimes it is because
the programmers are lazy enough to NOT read the specifications and keep bad
assumptions.

Since this thread is widely publiposted, it appears important to me to
remember to all programmers such "non-used yet standard" cases, to have them
dealt with (either by handling them, or by checking and discarding their
handling gracefully).
I acknowledge that real users are better off such setups.

I wouldn't want to try it and find out

Depend who you are. If you are a user, sure I agree. If you are a programmer
(I read this from the first group, microsoft.public.win2000.file_system), my
idea is that you SHALL try it and find out, at least before your [paying]
customers do (and ask you to change your program in a hurry.)


Antoine

 

[Guest]

127.53 GB or 32GB depending on what tool is used to format it.

http://www.microsoft.com/resources/...0/server/reskit/en-us/prork/prdf_fls_pxjh.asp