Uses for FAT Volumes
So why use FAT? It is the most popular and widely used PC file
system because it's been the only choice for millions of DOS users worldwide
since DOS arrived in the early 1980s.
Even on systems, such as NT, that can support additional file systems, FAT
can be the best choice. Multiboot systems (those with more than one OS
installed) usually have at least one FAT volume because many OSs, including
MS-DOS, Windows 3.x, Windows for Workgroups, Windows 95, OS/2, and NT, support
FAT. It can be the best choice for small volumes because its simple nature and
low overhead make it fast on these volumes. This advantage is also why FAT is
the only choice for floppy disk formats in NT.
NT can access FAT volumes of up to 4GB, but MS-DOS can recognize FAT
volumes of only up to 2GB. Therefore, keep the volume size to 2GB or smaller
when you create FAT volumes for use by both DOS and NT.
If you use FAT with another OS and switch to NT, you can keep your volumes
formatted as FAT until you're ready to switch to NTFS. However, after you
convert a FAT volume to NTFS, you can use that volume only with NTyou
can't convert that volume back to FAT without backing up, reformatting, and
restoring the volume.
To convert a FAT volume to NTFS, type CONVERT at the command prompt. The
format of the CONVERT command is CONVERT <drive:>/FS: NTFS [/V], where <drive>
is the designation of the drive you want to convert. The /V option tells CONVERT
to run in verbose mode, which gives detailed command output.
A final advantage of FAT is its ability to store programs that you can
access when the system boots under DOS. These programs include setup utilities
for configuring hardware devices and peripheral cards.
When you consider these advantages, don't forget FAT is not as secure as
NTFS. You can easily access FAT volumes with a DOS boot floppy, and FAT provides
only limited directory-level access security. For these reasons, I do not
recommend FAT for network shared volumes. Instead, consider NTFS, which has
file-level security and superior protection from physical access.
If you maintain a disk volume larger than 400MB, consider FAT's potential
to affect performance and usable disk space. Every FAT and NTFS volume uses
clusters, the basic unit of allocation to store disk files. FAT can have large
minimum cluster sizes that reduce the usable storage space on the volume.
Regardless of how small a file or part of a file is, it must take up at
least one cluster of disk space. When a file doesn't take up an entire cluster,
the portion of the cluster that contains no data is wasted. The larger the
cluster, the larger the waste. The amount of disk space wasted by minimum
cluster sizes on FAT volumes becomes exaggerated the larger the volume is.
Larger volumes have larger minimum cluster sizes. Therefore, large volumes that
store many small files will lose a lot of storable space because of the minimum
cluster size problem.
Table 1 lists the default minimum cluster sizes for various FAT
volume sizes. With large FAT volumes (256MB to 2048MB), the wasted drive space
is substantial and is reason enough to choose NTFS for these volumes.
NTFS File System
When NT came out, it included a new file system that Microsoft intended to
be robust, secure, and fast. This system, NTFS, has several advantages over
other file systems.
Security
NTFS's integration with NT security makes NTFS the best choice for volumes
requiring high levels of security. NTFS provides file-level security for setting
permissions on folders and files. These permissions make the most of the
existing local or domain NT accounts database, and you can have different
permissions on different files in the same folder.
Several types of file and folder permissions are available. They include
No Access, which excludes a specified user or group from any access to a
file or folder, and Full Control, which grants full control over
a file or folder, such as the ability to set permissions and take ownership of
it. File and folder permissions use the accounts database of the local NT
computer or domain. You can apply permissions to individual users, user groups,
or everyone.
NTFS also has better protection from unauthorized physical access than FAT:
Users can't access NTFS volumes by booting the system from a DOS diskette. This
restriction is because the NTFS driver that allows access to an NTFS volume
loads with NT.
Despite these security features, NTFS volumes are far from impervious to
intrusion. Utilities such as NTFSDOS and even one that works under LINUX (a UNIX
variant) can grant unauthorized access to NTFS volumes. NTFS can't prevent physical
access to files on NTFS volumes; instead, you have to physically lock away the
computer containing the data or use file encryption, which NTFS doesn't support.
However, third-party products such as Genio USA's CrypEdit or Regnoc Software's
Safe Program let you encrypt data on NTFS volumes.
Another NTFS security-related feature is preventing users from undeleting
files or folders removed from NTFS volumes. Even if the files exist on the
drive, NT doesn't give undelete programs physical disk access to work on an NTFS
volume. (You can, however, use a third-party DOS-based undelete program such as
Symantec's Norton Utilities and Microsoft's Undelete on FAT volumes. These
programs can recover deleted files but make no guarantees.) Although NTFS's
security features can be inconvenient for users with few or no security needs,
these features are central to NTFS and NT security and required for NT's
C2-level security certification.
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