Windows Filesystems
In a computer, a file system (sometimes written filesystem) is the way in which files are named and where they are placed logically for storage and retrieval. The DOS, Windows, OS/2, Macintosh, and UNIX-based operating systems all have file systems in which files are placed somewhere in a hierarchical (tree) structure. A file is placed in a directory (folder in Windows) or subdirectory at the desired place in the tree structure.
File systems specify
conventions for naming files. These conventions include the maximum number of
characters in a name, which characters can be used, and, in some systems, how
long the file name suffix
can be. A file system also includes a format for specifying the path to
a file through the structure of directories. Windows 2000 systems can support
the following file systems:
- FAT, FAT32
- NTFS - New Technology File System
- CDFS - Compact Disk File System
- UDF - Universal Disk Format for DVDs.
- EFS - Encrypting File System runs as a service and
is used to encrypt and decrypt files on an NTFS file system for security
purposes. The EFS is not a file system like NTFS since it does not create
partitions and control the placement of file data, it only is used to
control the encryption of data. See the Section called
"Security" in this document for more information on NFS.
FAT Filesystem Characteristics
Used with DOS, it can only support partitions up to 4 G. No spaces are allowed in the file name.
FAT32 or VFAT Filesystem Characteristics
VFAT - Virtual File Allocation Table introduced by Windows 95 which allows long file names. VFAT is not natively supported by Windows 2000.
- FAT32 filesystems support partitions up to 32GB.
- Filenames up to 255 characters long.
- Filenames begin with a letter and exclude " / \
[ ] : ; | = , ^ * ?
- The last part is the extension but spaces can be
used
- It supports file attributes used by DOS such as
read-only, archive, system, and hidden.
- Won't support running POSIX applications.
FAT partitions provide no local security, only share level security across a network.
NTFS Filesystem Characteristics
Windows 2000 NTFS file systems are newer than Windows NT NTFS file systems. In order for Windows NT and Windows 2000 to use the Windows 2000 file system together, the Windows NT system must have service pack 4 or later installed.
- Filenames up to 255 characters long
- Filenames preserve case but are not case sensitive.
- Filenames exclude " / \ < > : | * ?
- Supports built in file compression as a file
attribute. Compression is applied to files in a folder if that folder has
its compression attribute set. Also optionally sub folders and their
contents may be compressed. Compression is not supported if the cluster
size is above 4K in size. Moved files retain their compression
attribute, but if they are copied they will assume the compression
attribute of the target folder.
- Provides automatic transaction tracking of disk
activity for correcting corrupt or failed operations.
- Supports auditing.
- Provides sector sparing.
- There is a recycle bin for each user.
- Windows 16 bit and DOS environments can't use this
filesystem.
- A master file table is used to save individual file,
boot sector, disk structure, and file recovery information.
- Automatically makes 11 character DOS file names.
When the first 8 characters of long filenames match, the first four DOS
file names use the first for characters of the long name, the ~ and 1,
then2, etc. After the fourth duplicate name, the first two characters are
used, then the next four characters are hashed, then the ~ character then
a number. The first two duplicate file names may be: DOCU~1.DOC and
DOCU~2.DOC. The long extension is used as part of the extension for the
8.3 filename alias.Directory entries used by long filenames include 1 for
the 8.3 alias and 1 for each 13 characters in the long filename.
- Provides file logging ability and file recovery.
- Supports POSIX.
- Maximum file or partition size of 16 exabytes.
- Supports file sharing with MacIntosh clients.
- The disk is in 8M bands with a 2K file allocation
map between each band. The 2K map is a map for the associated 8M band.
This structure is called the BTREE and is used to reduce fragmentation.
- Supports file encryption with the Encrypting File
System (EFS) on Windows 2000.
- Allows volumes on remote computers or local
computers to be mounted as though they are part of the same partition they
are mounted on. This feature is available on Windows 2000.
- Disk quotas (tracking of disk space) on a user by
user basis are tracked.
- Removable media formatted in NTFS can be changed and
accessed without rebooting the system in Windows 2000 (not NT).
If installing DOS with NT, install DOS first so DOS will not corrupt the NT boot sector and stop the NT boot manager from running. Floppies are formatted as FAT, not NTFS.
CDFS
The file system that supports compact disks (CDs) is the Compact Disk File System (CDFS).
UDF
The file system that supports DVDs is the Universal Disk Format (UDF).
Filesystems and Windows Systems
|
Operating System
|
NTFS
|
FAT32
|
FAT
|
CDFS
|
UDF
|
HPFS
|
|
Windows
2000
|
Yes
|
Yes
|
Yes
|
Yes
|
Yes
|
No
|
|
Windows
NT 4.0
|
Yes
|
No
|
Yes
|
Yes
|
Yes
|
No
|
|
Windows
NT 3.51
|
Yes
|
No
|
Yes
|
Yes
|
No
|
Yes
|
|
Windows
98
|
No
|
Yes
|
Yes
|
Yes
|
Yes
|
No
|
|
Windows
95
|
No
|
Yes
|
Yes
|
Yes
|
Yes
|
No
|
|
Windows
3,x & WFW
|
No
|
No
|
Yes
|
Yes
|
No
|
No
|
|
OS/2
|
No
|
No
|
Yes
|
Yes
|
No
|
Yes
|
|
MS-DOS
|
No
|
No
|
Yes
|
Yes
|
No
|
No
|
The FAT file system does not support file compression on Windows 2000 systems. The file compression utilities with Windows 95 and Windows 98 are not supported by Windows 2000.
FAT file systems may be converted to NTFS file systems using the command line convert utility. Once converted, they may not be changed back to FAT.
Windows 2000 contains an NTFS file defragmentation utility which Windows NT does not contain.
Support for Security
Each object has an Access Control List (ACL) which defines users and group permissions for the object. Each entry (ACE - Access Control Entry) in an ACL defines the permissions a specific user or group has for the object. Access token attributes are added to the object's ACL. The user's security identifier (SID) is compared to the contents of the ACL to determine if the user has the correct privileges to access the object.
The NTFS file
system supports Access Control Lists for objects.
NTFS vs FAT
|
Criteria
|
NTFS5
|
NTFS
|
FAT32
|
FAT16
|
FAT12
|
|
Operting System |
Windows 2000
Windows XP Windows 2003 Server |
Windows NT
Windows 2000 Windows XP Windows 2003 Server |
DOS v7 and higher
Windows 98 Windows ME Windows 2000 Windows XP |
DOS
All versions of Microsoft Windows |
DOS
All versions of Microsoft Windows |
|
|
|||||
|
Limitations
|
|||||
|
Max Volume Size |
2TB
|
2TB
|
32GB for all OS.
2TB for some OS |
2GB for all OS.
4GB for some OS |
16MB
|
|
Max Files on Volume |
Nearly Unlimited
|
Nearly Unlimited
|
4194304
|
65536
|
|
|
Max File Size |
Limit Only by
Volume Size |
Limit Only by
Volume Size |
4GB minus 2 Bytes
|
2GB (Limit Only
by Volume Size) |
16MB (Limit Only
by Volume Size) |
|
Max Clusters Number |
Nearly Unlimited
|
Nearly Unlimited
|
4177918
|
65520
|
4080
|
|
Max File Name Length |
Up to 255
|
Up to 255
|
Up to 255
|
Standard - 8.3
Extended - up to 255 |
Up to 254
|
|
|
|||||
|
File System Features
|
|||||
|
Unicode File Names |
Unicode Character Set
|
Unicode Character Set
|
System Character Set
|
System Character Set
|
System Character Set
|
|
System Records Mirror |
MFT Mirror File
|
MFT Mirror File
|
Second Copy of FAT
|
Second Copy of FAT
|
Second Copy of FAT
|
|
Boot Sector Location |
First and Last Sectors
|
First and Last Sectors
|
First Sector and
Copy in Sector #6 |
First Sector
|
First Sector
|
|
File Attributes |
Standard and Custom
|
Standard and Custom
|
Standard Set
|
Standard Set
|
Standard Set
|
|
Alternate Streams |
Yes
|
Yes
|
No
|
No
|
No
|
|
Compression |
Yes
|
Yes
|
No
|
No
|
No
|
|
Encryption |
Yes
|
No
|
No
|
No
|
No
|
|
Object Permissions |
Yes
|
Yes
|
No
|
No
|
No
|
|
Disk Quotas |
Yes
|
No
|
No
|
No
|
No
|
|
Sparse Files |
Yes
|
No
|
No
|
No
|
No
|
|
Reparse Points |
Yes
|
No
|
No
|
No
|
No
|
|
Volume Mount Points |
Yes
|
No
|
No
|
No
|
No
|
|
|
|||||
|
Overall Performance
|
|||||
|
Built-In Security |
Yes
|
Yes
|
No
|
No
|
No
|
|
Recoverability |
Yes
|
Yes
|
No
|
No
|
No
|
|
Performance |
Low on small volumes
High on Large |
Low on small volumes
High on Large |
High on small volumes
Low on large |
Highest on small volumes
Low on large |
High
|
|
Disk Space Economy |
Max
|
Max
|
Average
|
Minimal on large volumes
|
Max
|
|
Fault Tolerance |
Max
|
Max
|
Minimal
|
Average
|
Average
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
No comments:
Post a Comment