Computing Methodologies -- Text Processing.

Both a tutorial on specifying systems and a complete reference to TLA, this is the distillation of 25 years of work by a renowned computer scientist. Divided into four parts, the first part contains all that most programmers and engineers need to know about writing specifications. The second part has advanced material for more sophisticated readers. The third and fourth parts comprise a reference manual for TLA+--both the language itself as well as its tools.

Computing Methodologies -- Text Processing.

Abstract: "Traditional methods for specifying and reasoning about concurrent systems work for real-time systems. Using TLA (the temporal logic of actions), we illustrate how they work with the examples of a queue and of a mutual-exclusion protocol. In general, two problems mustbe addressed: avoiding the real-time programming version of Zeno's paradox, and coping with circularities when composing real-time assumption/guarantee specifications. Their solutions rest on properties of machine closure and realizability."

Henry Lamport (1773-1826) married Elizabeth Clarke and immigrated from England to Woodstock, Ontario. Descendants lived in Ontario and elsewhere. Some descendants immigrated to Michigan in the United States, and their progeny lived in Michigan, Illinois, Wisconsin, Washington, Oregon, California and elsewhere.

Abstract: "The temporal logic of actions (TLA) is a logic for specifying and reasoning about concurrent systems. Systems and their properties are represented in the same logic, so the assertion that a system meets its specification and the assertion that one system implements another are both expressed by logical implication. TLA is very simple; its syntax and complete formal semantics are summarized in a little over a page. Yet, TLA is not just a logician's toy; it is extremely powerful, both in principle and in practice. This report introduces TLA and describes how it is used to specify and verify concurrent algorithms. The use of TLA to specify and reason about open systems will be described elsewhere. "

Abstract: "We show how to specify components of concurrent systems. The specification of a system is the conjunction of its components' specifications. Properties of the system are proved by reasoning about its components. We consider both the decomposition of a given system into parts, and the composition of given parts to form a system."

Abstract: "A method of writing proofs is proposed that makes it much harder to prove things that are not true. The method, based on hierarchical structuring, is simple and practical."