Wednesday, July 30, 2008

Attributes in NTFS

How many attributes do you know in NTFS?

Normally we will used to a few common attributes: Readonly, Archive, System, and Hidden. There are more than these actually. According to the documentation, we can have the following attributes for a file in NTFS: RASHCNETO.
  • Readonly:
  • For a file, applications can read the file, but cannot write to it or delete it.Applications can read the file but cannot write to it or delete it. For a directory, applications cannot delete it. * See here for more detail.
  • Archive:
  • The file or directory is an archive file. Applications use this attribute to mark files for backup or removal.
  • System:
  • The file or directory is part of the operating system, or is used exclusively by the operating system.
  • Hidden:
  • The file or directory is hidden. It is not included in an ordinary directory listing.
  • Compress:
  • The file or directory is compressed. For a file, this means that all of the data in the file is compressed. For a directory, this means that compression is the default for newly created files and subdirectories.
  • Not content indexed:
  • The file or directory is not to be indexed by the content indexing service.
  • Encrypted:
  • The file or directory is encrypted. For a file, this means that all data in the file is encrypted.For a directory, this means that encryption is the default for newly created files and subdirectories.
  • Temporary:
  • The file is being used for temporary storage. File systems avoid writing data back to mass storage if sufficient cache memory is available, because often the application deletes the temporary file shortly after the handle is closed. In that case, the system can entirely avoid writing the data. Otherwise, the data is written after the handle is closed.
  • Offline:
  • The data of the file is not immediately available. This attribute indicates that the file data has been physically moved to offline storage. This attribute is used by Remote Storage, the hierarchical storage management software. Applications should not arbitrarily change this attribute.
You can check all these from here and here. See also Potential issues involved in updating Windows NT IFS drivers to Windows 2000.
FILE_ATTRIBUTE_OFFLINE

When this new attribute is set on a file, the network timeout on the file is extended from 45 seconds to 1000 seconds. (This new default value can in turn be changed via the registry setting System\CurrentControlSet\Services\LanmanWorkStation\Parameters\ OffLineFileTimeoutInterval.) This new attribute is supported in the Windows 2000 redirector (RDR). It may also be backported to a Windows NT 4.0 service pack at some point (it is not in SP4), and possibly a Windows 98 service pack. It is intended for use by devices with high latencies, such as tape or optical disk libraries.

Use and interpretation of FILE_ATTRIBUTE_OFFLINE is optional, except for filter drivers that perform volume scans. Such drivers should ignore offline files by default, although they may offer advanced users the option of including offline files in the scan.