The Alpha Architecture Handbook. Digital Equipment Corporation, 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....This avoids the distortions caused by statistical timing, improves timing accuracy by several orders of magnitude, and bases scheduler decisions on these accurate usage times instead of potentially inaccurate approximations. A mutual exclusion protocol based on techniques developed by Lamport[30, 31] is used to avoid interlocked instructions in this subsystem since it is invoked from the critical trap, interrupt, and context switch paths in the kernel. A caching technique is used to make the resulting usage information efficiently available to the scheduler. The research on NUMA memory ....

....On the other hand, there is an additional cost in overhead, but it can be reduced to an acceptable level by careful design and implementation. An important component of this design is the use of algorithms for concurrent reading and writing without mutual exclusion developed by Lamport [30, 31]. Measurements of the Multimax implementation quantify the overhead increase caused by these measurement techniques and show that it is small. Statistical timing is based on sampling the use of each processor and assuming that the sample is representative. This is the most common technique for ....

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Leslie Lamport. Concurrent Reading and Writing of Clocks. Technical Report 27, Digital Equipment Corporation, Systems Research Center, Palo Alto, CA, 1988.

....that initial states of the lower level model correspond to legal, initial states of the higher level model. Then, we must show that for each transition that can be performed by the lower level model, there is a corresponding transition of the higher level model, or that it is a stuttering move [13] of the higher level model. These proof obligations are derived automatically by one of the proof rules that encodes the semantics of our logic for ST. Because refinement is a safety property, we can assume that if the state of the lower level model before a transition is performed maps to a ....

Leslie Lamport. The temporal logic of actions. Technical Report 71, Digital Equipment Corporation, Systems Research Center, Palo Alto, CA, December 1991.

....[23] with read aborts) have been studied previously. Notably, Pierce [47] presents a protocol implementing these semantics in a decentralized storage system using replication. This protocol is achieved by conjoining a protocol that implements pseudo regular semantics (regular semantics [32] with read aborts) with a write back protocol (repair) The penultimate step of a read operation is to write back the intended return value, which ensures that the return value of the read operation is written to a full quorum before it is returned. Our protocols go beyond this work by ....

Leslie Lamport. On interprocess communication. Technical report 8. Digital Equipment Corporation, Systems Research Center, Palo Alto, Ca, December 1985.

....semantics (linearizability with read aborts) have been studied previously. Notably, Pierce [28] presents a protocol implementing these semantics in a decentralized storage system. This protocol is achieved by conjoining a protocol that implements pseudo regular semantics (regular semantics [18] with read aborts) with a write back protocol (repair) The penultimate step of a read operation is to write back the intended return value, which ensures that the return value of the read operation is written to a full quorum before it is returned. The utility of write back hinges on full data ....

Leslie Lamport. On interprocess communication. Technical report 8. Digital Equipment Corporation, Systems Research Center, Palo Alto, Ca, December 1985.

....and in [SLL93b] the new proof techniques are used to verify nontrivial communication protocols. 4. 6 Comparison with Other Timed Models This section compares our timed model with the work of [AL91b, MMT91, VL92] The formalism that is used in [AL91b] is the Temporal Logic of Actions (TLA) [Lam91] extended with a new variable now that models time. A specification S consists of the conjunction of three formulas Init Pi L where Init represents the initial configurations of S, Pi is a safety property , and L is a liveness property . The subformula Init Pi corresponds to our safe timed ....

L. Lamport. The temporal logic of actions. Technical Report 79, Digital Equipment Corporation, Systems Research Center, December 1991.

....a clear need for being able to prove that a program executed in a certain environment performs correctly. Much work has been put into the development of formal methods for handling such reasoning, within recent years focusing especially on concurrent algorithms. TLA, the Temporal Logic of Actions [20], is one of the formal frameworks that has been the result of such research. In TLA, a system and its properties may be specified as logical formulas, allowing application of reasoning without any intermediate translation. The main problem with formal reasoning about concurrent systems, is that ....

....Part III concludes with three detailed examples on the use of TLP. The examples have been chosen so that they together form an extensive illustration of the different aspects of TLP reasoning. The first describes a traditional refinement proof, based on a simple example from Lamport s TLA report [20], which nicely illustrates some trivial safety proofs as well as a more complicated liveness analysis in connection with the refinement of the separate actions. The second, concerned with the correctness of a distributed spanningtree algorithm, presents a more complicated, non finite state example ....

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Leslie Lamport. The temporal logic of actions. Technical Report 79, Digital Equipment Corporation, Systems Research Center, December 1991.

....mathematical symbols which look at the first glance quite strange. It is necessary to change some parts of the syntax and or to add a graphical representation to make the formulae more readable. Our approach will be a semi graphical representation to support engineers. As mentioned by Lamport [19] and others it seems to be impossible to describe each kind of set of requirements and their combination with a graphical representation. The graphics are either not powerful enough or one has to use too many different symbols. Therefore we want to choose a presentation which supports the reader ....

L. Lamport, TLA in Pictures, technical research report, Digital Equipment Corporation, in http://www.research.digital.com/SRC/tla/,1994

....temporal logic, which is different from the linear time temporal framework we have been consistently using in this paper. It has long been observed that the property of being nonzeno cannot be formulated in linear time tl and needs branching time tl for its precise formulation. In a recent paper ( Lam95] Lamport makes this observation but suggests a method by which properties such as non zenoness can still be verified in a linear framework. We prefer to use the branching time logic ctl( EC82] for formulating the required property, as in premise N2, and present a single proof rule which is ....

L. Lamport. Proving possibiity properties. Technical Report 137, Digital Equipment Corporation, Systems Research Center, Palo Alto, July 1995.

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Leslie Lamport and Fred B. Schneider. Pretending Atomicity. research report 44, Digital Equipment Corporation, Systems Research Center, May 1989.

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Leslie Lamport. The temporal logic of actions. Research Report 79, Digital Equipment Corporation, Systems Research Center, December 1991. 26

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Lamport, L. The temporal logic of actions. Research report 79, Digital Equipment Corporation, Systems Research Center, Dec. 1991.

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Leslie Lamport and Fred B. Schneider. Pretending atomicity. Research Report 44, Digital Equipment Corporation, Systems Research Center, May 1989.

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Leslie Lamport. The temporal logic of actions. Research Report 79, Digital Equipment Corporation, Systems Research Center, December 1991.

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"The Ethernet - A Local Area Network", Version 1.0, Digital Equipment Corporation, Intel Corporation, Xerox Corporation, September 1980.

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"The Ethernet - A Local Area Network", Version 1.0, Digital Equipment Corporation, Intel Corporation, Xerox Corporation, September 1980.

....result. Unfortunately, the proof of the completeness theorem is combinatorial in nature and consists of the examination of a fairly large number of cases. For this reason, we have chosen to present the proof in a structured style following the spirit, albeit not the letter, of the proposal in [18]. We hope that this type of presentation will help the reader judge the correctness of the proof, in much the same way as it has helped us convince ourselves that the proof is, to the best of our knowledge, correct. Theorem 4.9 (Completeness) For all p; q 2 MPA q implies E p = q. Proof: ....

L. Lamport, How to write a proof, Research Report 94, Digital Equipment Corporation, Systems Research Center, Feb. 1993.

.... is entirely devoted to detailed proofs of our completeness theorems for bisimulation equivalence over MPA (A) Perhaps surprisingly, the proofs of the completeness theorems are rather involved, and, for this reason, we have chosen to present them in great detail in a style which is inspired by [24]. The non existence of a finite equational axiomatization for bisimulation equivalence over the language MPA is presented in Sect. 5. Finally, Sect. 6 is devoted to extensions of our main results to the language BPA 2 Preliminaries on Strings We begin with some mathematical preliminaries. In ....

....completeness theorem. Unfortunately, the proof of this result is combinatorial in nature and consists of the examination of a fairly large number of cases. For this reason, we have chosen to present the proof in a structured style following the spirit, albeit not the letter, of the proposal in [24]. We hope that this type of presentation will help the reader understand easily the details of the proof and judge its correctness, if he she wishes to do so. Theorem 29 (Completeness) For all MPA (A) terms P and Q, P Q implies MPA P = Q. Moreover, if P and Q are k bounded then MPA k ....

L. Lamport, How to write a proof, Research Report 94, Digital Equipment Corporation, Systems Research Center, Feb. 1993.

....that is, qualitative notions of time. They cannot, however, express quantitative notions of time. To remedy this expressive deficiency, new formalisms or extension to existing ones have been created which allow the representation of quantitative time. These include Temporal Logic of Actions[Lam90], Interval Temporal Logic[MM83] Durational Events[AR91] Real Time Logic[JLM88] Timed Propositional Temporal Logic[AH92] Asynchronous Propositional Temporal Logic[WME93] Metric Temporal Logic[AH90] Time constrained Reactive Automata[Bes91] Modecharts[JLM88] Timed Statecharts and ....

Leslie Lamport, A Temporal Logic of Actions, Technical Report 57, Digital Equipment Corporation, Systems Research Center, April 1, 1990. BIBLIOGRAPHY 157

....the reduced version of S . For example, S might be a multiprocess program containing critical sections, and S R might be obtained from S by replacing each critical section with a single atomicly executed statement. The first reduction theorem was proposed by Lipton [10] Several others followed [3 6, 9]. Our theorems strengthen these early results in three ways. First, in previous theorems, executions of the original and reduced specifications are completely separate; the executions are shown only to share certain properties, such as satisfying the same pre post conditions. In the reduction ....

Leslie Lamport and Fred B. Schneider. Pretending atomicity. Research Report 44, Digital Equipment Corporation, Systems Research Center, May 1989.

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The Alpha Architecture Handbook. Digital Equipment Corporation, 1992.

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L. Lamport. The temporal logic of actions. Technical Report 79, Digital Equipment Corporation, Systems ResearchCenter, Palo Alto, California, December 1991.

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L. Lamport. TLA . Digital Equipment Corporation, Systems Research Center, 1995. Internet: http://www.research.digital.com/SRC/tla/papers.html

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L. Lamport. The Operators of TLA . Digital Equipment Corporation, SRC Technical Note 1997-006a, 1997. Internet: http://www.research.digital.com/SRC/tla/papers.html 21

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L. Lamport. The Module Structure of TLA . Digital Equipment Corporation, SRC Technical Note 1996-002, 1996. Internet: http://www.research.digital.com/SRC/tla/papers.html

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Leslie Lamport. How to write a proof. Research Report 94, Digital Equipment Corporation, Systems Research Center, February 1993.

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