What's the difference between FAT32 and Extended FAT File System ?

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98 Guy

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Extended FAT File System:

http://msdn2.microsoft.com/en-us/library/aa914353.aspx

Vista now has eFAT (or exFAT) compatibility with SP1.

Not sure about XP.

So what are the key technical differences between eFAT and FAT32?

According to this:

http://en.wikipedia.org/wiki/ExFAT

- theoretical max file size 2^64 bytes (16 Exabytes) vs 4 Gb (2^32)
- cluster size of up to 2^255 bytes vs 32 mb
(that seems wrong - a cluster can be larger than max file size?)
(FAT32 spec is 32 kb, not 32 mb)
- support for more than 1000 files in a single directory
(what are they comparing it to? FAT32's limit is more than 1000)

- support for access control lists
- support for Transaction-Safe FAT File System (TFAT)

eFAT seems to be Micro$oft's preferred propriatary solution for
portable and fixed storage beyond 4 or 8 gb. Most likely because
FAT32's propriatary status is murky and they don't want it to be
adopted industry-wide as portable storage and devices transitions to
higher capacities (where the currently used but public domain FAT-16
is not able to go).

Does this mean that Vista can be installed and run from an eFAT
drive? Why else would Vista need eFAT compatibility? A slaved drive
or device would most likely be connected via USB so it's not clear why
the file system of the device or drive is relavent.
 
Re: What's the difference between FAT32 and Extended FAT File System ?

98 Guy <98@Guy.com> wrote:


>eFAT seems to be Micro$oft's preferred propriatary solution for
>portable and fixed storage beyond 4 or 8 gb. Most likely because
>FAT32's propriatary status is murky and they don't want it to be
>adopted industry-wide as portable storage and devices transitions to
>higher capacities (where the currently used but public domain FAT-16
>is not able to go).

The Wikipedia article says this is used mostly for Flash drives and
was "introduced with Windows Embedded CE 6.0. exFAT is used where the
NTFS file system is not a feasible solution, due to data structure
overhead". I've never heard of a hard drive partition using this
system.

>Does this mean that Vista can be installed and run from an eFAT
>drive?

Presumably, but I don't know.

>Why else would Vista need eFAT compatibility?

So it could read from and write to such a drive.

>A slaved drive or device would most likely be connected via USB
> so it's not clear why the file system of the device or drive is relavent.

Regardless of the connection method, the OS would have to be able to
make sense of the file system on the device.

--
Tim Slattery
MS MVP(Shell/User)
Slattery_T@bls.gov
http://members.cox.net/slatteryt
 
Re: What's the difference between FAT32 and Extended FAT File System ?

Tim Slattery wrote:

> > A slaved drive or device would most likely be connected via USB
> > so it's not clear why the file system of the device or drive is
> > relavent.
>
> Regardless of the connection method, the OS would have to be able
> to make sense of the file system on the device.

Maybe I'm wrong here, but my impression of a USB-attached mass storage
device is that it's native file system is not directly accessible (or
knowable) to the host computer, and that the host system accesses
files on the device through a higher driver layer.

For example, can an NT-based machine format a USB memory stick or
external hard drive with an NTFS file system? Presumably if it can,
then it would not be accessible to a win-98 system. But my thesis
says they can't be formatted as NTFS.
 
Re: What's the difference between FAT32 and Extended FAT File System ?

98 Guy <98@Guy.com> wrote:


>Maybe I'm wrong here, but my impression of a USB-attached mass storage
>device is that it's native file system is not directly accessible (or
>knowable) to the host computer, and that the host system accesses
>files on the device through a higher driver layer.

I don't believe that's right.

>For example, can an NT-based machine format a USB memory stick or
>external hard drive with an NTFS file system? Presumably if it can,
>then it would not be accessible to a win-98 system. But my thesis
>says they can't be formatted as NTFS.

I see posts in ms.p.windowsxp.general from time to time that talk
about formatting USB sticks as NTFS. And yes, in that case it would
not be usable by a Win98 system.

--
Tim Slattery
MS MVP(Shell/User)
Slattery_T@bls.gov
http://members.cox.net/slatteryt
 
Re: What's the difference between FAT32 and Extended FAT File System ?

"Tim Slattery" <Slattery_T@bls.gov> wrote in message
news:51noq39lnp5ba0dp9tkbt16p788ufj3qb1@4ax.com...
> 98 Guy <98@Guy.com> wrote:
>
>
>>Maybe I'm wrong here, but my impression of a USB-attached mass storage
>>device is that it's native file system is not directly accessible (or
>>knowable) to the host computer, and that the host system accesses
>>files on the device through a higher driver layer.
>
> I don't believe that's right.
>
>>For example, can an NT-based machine format a USB memory stick or
>>external hard drive with an NTFS file system? Presumably if it can,
>>then it would not be accessible to a win-98 system. But my thesis
>>says they can't be formatted as NTFS.
>
> I see posts in ms.p.windowsxp.general from time to time that talk
> about formatting USB sticks as NTFS. And yes, in that case it would
> not be usable by a Win98 system.

Format a USB drive with NTFS file system
http://www.pctipsbox.com/format-a-usb-drive-with-ntfs-file-system/

Windows XP: Format backup drives with NTFS
http://www.microsoft.com/windowsxp/using/setup/tips/advanced/ntfs.mspx

The Old New Thing : How can I format my USB drive as NTFS?
http://blogs.msdn.com/oldnewthing/archive/2004/04/05/108205.aspx

--
Glen Ventura, MS MVP Windows, A+
http://dts-l.net/
http://dts-l.net/goodpost.htm
 
RE: What's the difference between FAT32 and Extended FAT File System ?

How long have you have the computer for and also when was the last time u
defraged it

"98 Guy" wrote:

> Extended FAT File System:
>
> http://msdn2.microsoft.com/en-us/library/aa914353.aspx
>
> Vista now has eFAT (or exFAT) compatibility with SP1.
>
> Not sure about XP.
>
> So what are the key technical differences between eFAT and FAT32?
>
> According to this:
>
> http://en.wikipedia.org/wiki/ExFAT
>
> - theoretical max file size 2^64 bytes (16 Exabytes) vs 4 Gb (2^32)
> - cluster size of up to 2^255 bytes vs 32 mb
> (that seems wrong - a cluster can be larger than max file size?)
> (FAT32 spec is 32 kb, not 32 mb)
> - support for more than 1000 files in a single directory
> (what are they comparing it to? FAT32's limit is more than 1000)
>
> - support for access control lists
> - support for Transaction-Safe FAT File System (TFAT)
>
> eFAT seems to be Micro$oft's preferred propriatary solution for
> portable and fixed storage beyond 4 or 8 gb. Most likely because
> FAT32's propriatary status is murky and they don't want it to be
> adopted industry-wide as portable storage and devices transitions to
> higher capacities (where the currently used but public domain FAT-16
> is not able to go).
>
> Does this mean that Vista can be installed and run from an eFAT
> drive? Why else would Vista need eFAT compatibility? A slaved drive
> or device would most likely be connected via USB so it's not clear why
> the file system of the device or drive is relavent.
>
 
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