Windows File and Print Services - MCTS Guide to Microsoft Windows Server 2008 Active Directory Configuration - page 212

6. Open the text document and verify that it contains only your name. Exit Notepad.
7. Log off Vista, but stay logged on to your server.
File Compression and Encryption File compression and encryption on an NTFS
volume are implemented as file attributes, like the Read-only and Hidden attributes. One caveat:
These attributes are mutually exclusive, so a file can't be both compressed and encrypted. You
can set only one of these two attributes.
Files can be compressed and accessed without users needing to take any explicit action to
uncompress them. When a compressed file is opened, the OS uncompresses it automatically. On
NTFS volumes, you can enable file compression on the entire volume, a folder and its contents,
or a file. You can enable compression on an entire volume at the time you format it or by click-
ing the “Compress this drive to save disk space” option in the General tab of the volume's
Properties dialog box. If you compress a drive when you format it, all files stored on the volume
are compressed. When you compress a volume after it has been formatted, you're asked whether
you want to compress only the root of the drive or the root of the drive plus all subfolders and
files. If you compress just the root, only new files placed in the root of the volume are com-
pressed. If you compress all subfolders and files, all existing files plus new files are compressed
on the entire volume.
You can compress a single folder as well. The same rules for the volume apply to a folder. If
you compress only a folder, only new files added to the folder are compressed, and existing fold-
ers and files are left alone. If you apply changes to this folder, subfolders, and files, all new and
existing files in the folder and its subfolders are compressed. By default, compressed folders and
files can be identified by their blue filenames. A single file can be compressed by setting its com-
pression attribute.
When copying or moving files, you should be aware of these rules for compression
behavior:
• Files copied to a new location inherit the compression attribute from the parent container.
So whether a file is compressed or not, if it's copied to a folder or volume that has the
compression attribute set, the file is compressed. If the destination's compression attribute
is not set, the file isn't compressed.
• Files moved to a new location on the same volume retain their current compression attrib-
utes. Files moved to a different volume inherit the compression attribute from the parent
container. This behavior happens because files moved to a different volume are actually
copied to the new volume and deleted from the original volume, so the behavior is the
same as with copied files.
File encryption on NTFS volumes is made possible by Encrypting File System (EFS) and
works in a similar manner to file compression. You can set the encryption attribute on a file
or folder but not on a volume. If encryption is set on a folder, as with compression, you're
prompted with the option to set the attribute on the folder only or on the folder, subfolders,
and files. By default, encrypted folders and files can be identified by their filenames displayed
in green.
The rules for encryption behavior when copying and moving files are different from the rules
for compression:
• Encrypted files that are copied or moved always stay encrypted, regardless of the destina-
tion's encryption attribute. The exception is if the file is copied or moved to a FAT volume,
in which case the file is decrypted because FAT doesn't support encryption.
• Unencrypted files that are moved or copied to a folder with the encryption attribute set are
always encrypted.
Encrypted files can usually be opened only by the user who encrypted the file. However, this
user can designate other users who are allowed to access the file. In addition, in a domain envi-
ronment, the domain Administrator account is designated as a recovery agent. A designated
recovery agent can decrypt a file if the user account that encrypted it can no longer access it. This