It is my great privilege and pleasure to announce the availability of FreeBSD 5.1-RELEASE. This release continues FreeBSD on the path of advanced multiprocessor and application thread support and includes many improved and widely-sought features:

• Experimental 1:1 and M:N thread libraries provide kernel support for efficient application multithreading.
• Support for Physical Address Extensions enables Pentium Pro and higher CPUs to access up to 64GB of RAM
• Experimental Name Service Switch infrastructure allows enterprises to seamlessly integrate with LDAP and Active Directory services.
• Enhanced "jail" management, allowing one server to provide many different "virtual machines" with reduced administrator workload.
• New device drivers include support for IBM/Adaptec ServeRAID controllers, expanded support for USB 2.0 and USB Ethernet adapters, and Promise Serial ATA controllers.
• Experimental support for the amd64 platform allows FreeBSD to run on single processor AMD Opteron systems.