ServersLearn Windows XP Professional: Administration of Resources (Page 2) Page 2

Learn Windows XP Professional: Administration of Resources (Page 2) Page 2

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FAT32 is
supported by Windows XP Professional, as well as a number of
the newer Microsoft Operating systems. FAT32 was first
introduced with Microsoft Windows 95 OSR2 and the major
differences between FAT and FAT32 are volume and cluster
sizes for the most part as well as the fact that only Microsoft
Operating systems can natively access FAT32.  

The FAT32
file system can support drives up to 2 terabytes in size (in
theory), and because it uses space more efficiently, FAT32
uses smaller clusters (that is, 4,096 byte clusters for
drives up to 8 GB in size), resulting in more efficient use
of disk space relative to large FAT16 drives.

File System Cluster Sizes

Partition Size   Cluster Size
0M to less than 260MB 512 bytes
260MB through 8GB 4,096 bytes
8GB through 16GB 8,192 bytes
16GB through 32GB 16,384 bytes
32GB through 2TB 32,768 bytes

The 50
files I mentioned in the FAT16 section, all 1024 bytes (1KB)
in actual size, would use up only 409,600 bytes on a 16GB
partition formatted with FAT16 and only 204,800 bytes on a
8GB partition. As you can see however, we are now running
into the issue with FAT32 drives with 80GB and 100GB
partitions that we did a few years ago under FAT16 — wasted
space. Those same 50 files would use 819,200 bytes on either
of the two large drives I mentioned. There’s a Windows 2000
Professional and XP Professional catch, however.

While the
FAT32 file system can support drives up to a standard theoretical
size of 2 terabytes, (it “can” be jury-rigged under

Windows Millennium Edition to support partitions of up to 8

Windows 2000 Professional

XP Professional

a volume
larger than 32 GB in size using their native FAT32 file

The FastFAT
driver can mount and support volumes larger than 32 GB that
use the FAT32 file system, such as those created locally by
Windows 98 or ME in dual boot configuration, (subject to
other limits listed here for

Windows 98, ME and 2000

here for Windows XP
), but you cannot


one using the Format tool from within either Windows 2000
Professional or XP Professional. If you attempt to format a
FAT32 partition larger than 32 GB, the format fails near the
end of the process with the following error message: Logical
Disk Manager: Volume size too big.

In summary,
the advantages of the FAT32 file system are:

  • FAT32 allocates disk space much more efficiently than FAT16.

  • The root folder on a FAT32 drive is not restricted in the
    number of entries in the root folder as was FAT16.

  • FAT32 is a more robust file system than FAT16 was. FAT32 has
    the ability to relocate the root directory and use the
    backup copy of the FAT instead of the default copy. In
    addition, the boot record on FAT32 drives has been expanded
    to include a backup of critical data structures. This means
    that FAT32 volumes are less susceptible to a single point of
    failure than FAT16 volumes.

Just as there were disadvantages to the FAT16 file system,
so there are in FAT32 as well:

  • FAT32
    volumes are not accessible from any other operating systems
    other than certain Microsoft ones.

  • FAT32
    partition sizes are limited to 32GB in size using the native
    FAT32 file system format tools under Windows 2000 and
    Windows XP. (The maximum size is

    127.5 GB practical and 2TB standard theoretical.

  • There is no
    native file level security, compression or encryption
    available in the FAT32 file system.

Below is a
table of Microsoft Operating systems which support native
access to the FAT32 file system.

Operating System  Supports FAT32 
Windows XP Professional Yes  
Windows XP Home Yes  
Windows 2000 Professional Yes  
Windows Millennium Edition Yes  
Windows 98 and Second Edition Yes  
Windows 95 OSR2 and OSR2.5 Yes  
Windows NT4  Workstation No
Windows 95 Gold (Original Release) No
Windows NT3.5x  Workstation No
MS-DOS (versions 3.3 and higher) No


There is no test requirement to memorize the FAT32 tables
either, but again, it’s good to understand the “how and why”
of it. Also, it is never a “best practice” to dual boot any
workstation or server that has sensitive data on it with any
file system installed that cannot secure those files or any
operating system that threatens that security. This would
include the FAT32 file system.

answers to some common questions about the FAT32 File
System, you can look up

Q253774 at the Microsoft PSS webpage.

For more
information on the Limitations of FAT32 File System on
Windows 98, ME and 2000, you can look up

Q184006 at the Microsoft PSS webpage.
You can find the
information for the limitations of the FAT32 File System in
Windows XP information available at

You will also find the maximum partition sizes,
both practical and theoretical listed there as well.


maximum single file size on a FAT32 partition is 4 GB
regardless of the size of the partition.

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