The x-kernel is an object-based protocol implementation framework It defines an interface that protocols use to invoke operations on one another (this is called the Uniform Protocol Interface, or UPI), and a collection of libraries for manipulating messages, participant addresses, events, associative memory tables (maps), and threads.
Version 3.3 represents a re-engineering of most of the x-kernel libraries, a consolidation of the platforms on which the x-kernel runs, and the addition of a protocol simulation platform. Like the previous version, Version 3.3 completely isolates the protocol from the underlying operating system. As a result, protocol source code can be moved from one platform to another without modification. However, there are several minor differences between the Version 3.2 and 3.3 interfaces.
Sections 2 through 11 of this manual define the Uniform Protocol Interface and the libraries that make up the x-kernel . Sections 12--14 then describe the procedures for configuring and running the x-kernel , and for releasing protocols.