A predictive analysis takes an execution trace as input and discovers concurrency bugs without accessing the program source code. A sound predictive analysis reports no false positives, which sounds like a property that can be defined easily, but which has been defined in many different ways in previous work. In this paper, we unify, simplify, and generalize those soundness defInitions for analyses that discover concurrency bugs that can be represented as a consecutive sequence of events. Our soundness defInition is graph based, separates thread-local properties and whole-execution properties, and works well with weak memory executions. We also present a three-step proof recipe, and we use it to prove six existing analyses sound. This includes the first proof of soundness for a predictive analysis that works with weak memory.

We describe a new algorithm SplitMix for an object-oriented and splittable pseudorandom number generator (PRNG) that is quite fast: 9 64-bit arithmetic/logical operations per 64 bits generated. A conventional linear PRNG object provides a generate method that returns one pseudorandom value and updates the state of the PRNG, but a splittable PRNG object also has a second operation, split, that replaces the original PRNG object with two (seemingly) independent PRNG objects, by creating and returning a new such object and updating the state of the original object. Splittable PRNG objects make it easy to organize the use of pseudorandom numbers in multithreaded programs structured using fork-join parallelism. No locking or synchronization is required (other than the usual memory fence immediately after object creation). Because the generate method has no loops or conditionals, it is suitable for SIMD or GPU implementation.

Creating components based on concurrent and parallel algorithms and data structures often requires more attention to "engineering" issues not seen with most other libraries. Components created in the "obvious" way sometimes turn out to be wrong, to perform poorly, or are unusable in most applications, because the abstractions in which they are expressed are leaky, imprecise, or incorrectly specified. While many of these issues are encountered in other aspects of concurrent programming, the impact is accentuated when they continue to leak through to APIs provided by library components. This presentation surveys some examples and lessons learned from the design, implementation, and applications of the java.util.concurrent library, including those surrounding memory models, resource management and garbage collection, thread management, optimization, and code generation.

Solving large, irregular graph problems efficiently is challenging. Current software systems and commodity multiprocessors do not support fine-grained, irregular parallelism well. We present XWS, the X10 Work Stealing framework, an open-source runtime for the parallel programming language X10 and a library to be used directly by application writers. XWS extends the Cilk work-stealing framework with several features necessary to efficiently implement graph algorithms, viz., support for improperly nested procedures, global termination detection, and phased computation. We also present a strategy to adaptively control the granularity of parallel tasks in the work-stealing scheme, depending on the instantaneous size of the work queue. We compare the performance of the XWS implementations of spanning tree algorithms with that of the hand-written C and Cilk implementations using various graph inputs. We show that XWS programs (written in Java) scale and exhibit comparable or better performance.

We present two new nonblocking and contention-free implementations of synchronous queues ,concurrent transfer channels in which producers wait for consumers just as consumers wait for producers. Our implementations extend our previous work in dual queues and dual stacks to effect very high-performance handoff. We present performance results on 16-processor SPARC and 4-processor Opteron machines. We compare our algorithms to commonly used alternatives from the literature and from the Java SE 5.0 class java. util. concurrent. SynchronousQueue both directly in synthetic microbenchmarks and indirectly as the core of Java's Thread-PoolExecutor mechanism (which in turn is the core of many Java server programs).Our new algorithms consistently outperform the Java SE 5.0 SynchronousQueue by factors of three in unfair mode and 14 in fair mode; this translates to factors of two and ten for the ThreadPoolExecutor. Our synchronous queues have been adopted for inclusion in Java 6.

Web services are emerging technologies to reuse software as services over the Internet by wrapping underlying computing models with XML. Web services are rapidly evolving and are expected to change the paradigms of both software development and use. This panel will discuss the current status and challenges of Web services technologies.

Aliasing in object-oriented systemsAliasing is naturally endemic in object-oriented programs.Every object in an object-oriented program can refer to many other objects, so the overall topology of a program is a general graph.The state of an object can rely on the states of all of the other objects it references.Aliasing occurs when one object is reachable via multiple paths, usually because it is referenced by several other objects.Aliasing results in 'action at a distance'-operations on one object can affect the logical state of apparently unrelated objects that (perhaps indirectly) refer to it.The articles in this issue address the costs and benefits of aliasing in a number of ways.The first three articles focus on programming techniques and language features that allow programmers to control aliasing and its effects.Boris Bokowski and Jan Vitek describe how Confined Types can be used to restrict potential aliasing within programs.John Boyland's article on Alias Burying describes how variables holding unique references to objects can be implemented without special programming language support.Günther Kniesel and Dirk Theisen describe how Java can be extended to support types that provide read-only access to objects, thus eliminating some of the unwanted effects of aliasing without restricting the program's topology.While new languages and language features can help reduce and control aliasing, compilers today must deal with programs filled with potential aliases.The article by Anthony Hosking et al. describes how partial redundancy elimination can support compiler-level optimizations in the presence of aliasing.Finally, Olivier Zenda and Dominque Colnet evaluate the use of aliasing in the implementation of the SmallEiffel compiler.This issue, then, represents the state of practice in dealing with aliasing in object-oriented systems.

Everyone is building a distributed systems these days, but the "how" has become a matter for religious debate and the "why" is often neglected completely.This panel brings together a variety of practitioners to explain the joys and woes of building a distributed system including: .why a distributed solution was chosen .what middleware was selected and why .what issues and gotchas reared their ugly heads and what was done about it

No abstract available.

Article Free Access Share on Developing an undergraduate software engineering program in a liberal arts college Authors: Paul T. Tymann State University of New York, Oswego, New York State University of New York, Oswego, New YorkView Profile , Douglas Lea State University of New York, Oswego, New York State University of New York, Oswego, New YorkView Profile , Rajendra K. Raj State University of New York, Oswego, New York State University of New York, Oswego, New YorkView Profile Authors Info & Claims SIGCSE '94: Proceedings of the twenty-fifth SIGCSE symposium on Computer science educationMarch 1994Pages 276–280https://doi.org/10.1145/191029.191143Published:12 March 1994Publication History 4citation146DownloadsMetricsTotal Citations4Total Downloads146Last 12 Months6Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

The object-oriented design process is investigated within the classic software development classification of Analysis, Design, and Implementation.When all development is performed using object oriented methods, OOD is best characterized as a transformational process, mapping declarative descriptions of objects and classes to implementation plans.Subphases of class design, system design, and program design accommodate and rationalize 00 practices including abstraction, prototyping, refinement, bottom-up composition, delegation, interoperablity, clustering objects into processes, resource management design, tuning and optimization.

Article Free Access Share on Formal techniques for OO software development Authors: Pierre America Philips Research Laboratories Philips Research LaboratoriesView Profile , Derek Coleman HP-Lab Bristol HP-Lab BristolView Profile , Roger Duke University of Queensland University of QueenslandView Profile , Doug Lea Syracuse University & SUNY-Oswego Syracuse University & SUNY-OswegoView Profile , Gary Leavens Iowa State University Iowa State UniversityView Profile Authors Info & Claims OOPSLA '91: Conference proceedings on Object-oriented programming systems, languages, and applicationsNovember 1991 Pages 166–170https://doi.org/10.1145/117954.117967Published:01 November 1991Publication History 2citation376DownloadsMetricsTotal Citations2Total Downloads376Last 12 Months13Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF