Full volume encryption
Full Volume Encryption, or FVE, is a method for encrypting a single partition, either physical or virtual, on a hard drive. It is different than Full Disk Encryption as parts of the disk are left unencrypted.
Implementations
BitLocker Included with certain versions of Microsoft Windows as of Vista.
FileVault Disk Encryption Included with certain versions of Apple Mac OS X.
FreeOTFE A free and open source FVE program for Microsoft Windows and Windows Mobile PDAs.
TrueCrypt A free and open source FVE program for Microsoft Windows.