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Learn Windows XP Professional in 15 Minutes a Week: Implementing and Conducting Administration of Resources

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by Jason Zandri

Welcome to this week’s installment of
Learn Windows XP Professional in 15 minutes a week, the sixth in the series.
With this article I will begin focusing on the next section of material which centers on Implementing
and Conducting Administration of Resources on Windows XP
Professional, this one covering Windows XP Professional file

Jason Zandri’s latest article in the Learning Windows XP Professional in 15 Minutes a Week series focuses on implementing and conducting the administration of resources on Windows XP Professional and specifically covers Windows XP Professional file systems.

Implementing and Conducting
Administration of Resources

File System

To have a
good understanding of how and why you can set up or deny
access to data on a Windows XP Professional system, you need
to have an underlying understanding of any native file
security that may or may not be in place.

One place
to start would be the file system the operating system is

Windows XP
Professional supports the three major computer files systems
of File Allocation Table (commonly known as FAT or FAT16),
FAT32 and NTFS.


Allocation Table (commonly known as FAT or FAT16) is
supported by Windows XP Professional, all Windows operating
systems, and DOS, as well as a host of other non-Microsoft OSes.

FAT is allocated in clusters, the size of which are
determined by the size of the partition. The larger the
partition, the larger the cluster size. The larger the
cluster size, the more space “required” when using it to
store data.

FAT file
system cluster sizes

Partition Size     Cluster Size    FAT Type
0M to less than 16MB 4,096 bytes 12-bit
16M through 128MB 2,048 bytes 16-bit
128 through 256MB 4,096 bytes 16-bit
256 through 512MB 8,192 bytes 16-bit
512 through 1,024MB 16,384 bytes 16-bit
1,024 through 2,048MB 32,768 bytes 16-bit

As you can
see, with a 2GB partition size, (the maximum allowed under
FAT16 in most cases) if you were to save 50 different files,
all 1024 bytes (1KB) in actual size (or to have 50 fractions
of larger files “fall over” to the next cluster by that same
amount), the amount of hard drive space used up would be
1,638,400 bytes (a little over 1 MB), for 51,200 bytes of
actual data.

You can
obviously see that this is a serious problem when there are
thousands of small *.DLLs and other types of small files.

Also, with
the advent of super-inexpensive hard drives that are 80GB in
size, you can see where using FAT would be an issue as well.

In summary,
there are “advantages” for using the FAT file system on a
Windows XP Professional installation:

  • MS-DOS, Windows 95, Windows 98, Windows NT, Windows 2000,
    and some UNIX operating systems can use FAT16. If there is
    some reason to dual boot the system, FAT16 allows you the
    greatest number of options.

  • There are many software tools that can address problems and
    recover data on FAT16 volumes.

  • If you have a startup failure, you can start the computer by
    using a bootable floppy disk to troubleshoot the

  • FAT16 is efficient, in speed and storage, on volumes smaller
    than 256 MB. 

(Those 50
files I mentioned above, all 1024 bytes (1KB) in actual
size, would use up “only” 409,600 bytes on a 400MB partition
formatted with FAT16 and “only” 204,800 bytes on a 250MB

There are
also some FAT16 disadvantages as well:

  • The root
    folder (usually the C: drive) has a

    limit of 512 entries
    . The use of long file names can
    significantly reduce the number of available entries.

  • FAT16 is limited to 65,536 clusters, but because certain
    clusters are reserved, it has a practical limit of 65,524.
    The largest FAT16 volume on Windows 2000 and Windows XP
    Professional is limited to 4 GB and uses a cluster size of 64 KB. To maintain compatibility
    with MS-DOS, Windows 95, and Windows 98, a volume cannot be
    larger than 2 GB. (Those 50 files I mentioned above, all
    1024 bytes (1KB) in actual size, would use up 3,276,200
    bytes of hard drive space to store 51,200 bytes of actual
    data on a 4 GB FAT16 partition used in this scenario.)

  • FAT16 is inefficient on larger volume sizes, as the size of
    the cluster increases. We have seen this in the examples

  • The boot sector is not backed up on FAT16 partitions.
    Because FAT16 does not include a backup copy of critical
    data structures, they are susceptible to single point of
    failure issues, more so than other file systems.
  • There is no
    native file level security, compression or encryption
    available in the FAT16 file system.

Below is a
table of Microsoft Operating systems and which file systems
they can natively access.

Operating System  Supports NTFS  Supports FAT32  Supports FAT  Max Partition
Windows XP Professional Yes   Yes   Yes   4GB
Windows XP Home Yes   Yes   Yes   4GB
Windows 2000 Professional Yes   Yes   Yes   4GB
Windows Millennium Edition No Yes   Yes   2GB
Windows 98 and Second Edition No Yes   Yes   2GB
Windows 95 OSR2 and OSR2.5 No Yes   Yes   2GB
Windows NT4  Workstation Yes   No Yes   4GB
Windows 95 Gold (Original Release) No No Yes   2GB
Windows NT3.5x  Workstation Yes   No Yes   4GB
MS-DOS (versions 3.3 and higher) No No Yes   * see below


There is no test requirement to memorize these tables, but
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.

maximum FAT partition that can be created and accessed by
the operating systems listed above is 2GB in most cases. 4GB FAT
partitions can be created and properly accessed only under
those operating systems specifically listed above. A dual boot NT family
of operating system can create a 4GB FAT partition and a
lower level OS such as Windows 98 may be able to see data on
it, however, issues will arise when data access is attempted
above the 2GB threshold that the OS normally uses.

For more
information on the Maximum Partition Size Using the FAT16
File System in Windows XP, you can look up

Q310561 at the Microsoft PSS webpage

“OSR” in “Windows 95 OSR2 and OSR2.5” stands for OEM Service

“OEM” in “OEM Service Release” stands for Original Equipment

For more
information on

Accessing FAT16 Drives Larger Than 2 GB
, or

Maximum Partition Size Using FAT16 File System
, feel
free to follow the links I have provided to the Microsoft
web site.

* There
are some exceptions, but for the most part, DOS 3.3 and
higher can access up to 2GB of single partition space, as
outlined in Q67321 at the Microsoft PSS webpage. The

MS-DOS Partitioning Summary (Q69912)
names some
exceptions and points out the fact that some earlier
versions didn’t support many of today’s FAT16 standards.


maximum single file size on a FAT16 partition is 2 GB
regardless of the fact that some OSes can have a 4GB

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