Programming Toolkit Research Articles

Design for AJACS, yet another Java constraint programming framework

This article introduces AJACS (Another Java Constraint Programming System), a toolkit for Concurrent Constraint programming implemented in the Java language. It comes as a successor to our previous work in implementing Constraint Programming idioms in Java, GC [5], in that it represents an attempt to deal with some of GC's inadequacies in terms of performance whilst providing a setting which is adequate to express problems in a way that can be easily solved in a parallel execution environment, as provided by a concurrent programming setting.We claim that AJACS provides a very flexible toolkit for use in general applications that may benefit from constraint programming techniques. We also claim that AJACS allows for the coding of CSP problems whose solution is amenable to a practically effortless parallelization.

Coordinating Java agents over the WWW

We introduce Jada, a programming toolkit for coordinating agents written in Java. Coordination among either concurrent threads or distributed Java objects is achieved via shared object spaces. By exchanging objects through object spaces, Java agents or applets can exchange data or synchronize their actions over the Internet, a LAN, a single host, or even inside a Java-enabled browser. The access to an object space is performed using a set of methods of an ObjectSpace object. Such operations inspired by the Linda language are powerful enough to solve several coordination problems. Moreover, we show how Jada can be used as a coordination kernel for more complex coordination architectures.

Slisp: A Flexible Software Toolkit for Hybrid, Embedded and Distributed Applications

JAMES F. BRINKLEY AND JEFFREY S. PROTHEROStructural Informatics Group, Digital Anatomist Program, Departmentof Biological Structure,Box 357420,University of Washington, Seattle, WA 98195, U.S.A. (email: brinkley@u.washington.edu,jsp@biostr.washington.edu)SUMMARYWe describe Slisp (pronounced ‘Ess-Lisp’), a hybrid Lisp–C programming toolkit for the development ofscriptable and distributed applications. Computationally expensive operations implemented as separateC-coded modules are selectively compiled into a small Xlisp interpreter, then called as Lisp functions in aLisp-codedprogram.The resulting hybrid programmay run in severalmodes: as a stand-alone executable,embedded in a different C program, as a networked server accessed from another Slisp client, or as anetworked server accessed from a C-coded client. Five years of experience with Slisp, as well experiencewith other scripting languages such as Tcl and Perl, are summarized. These experiences suggest that Slispwill be most useful for mid-sized applications in which the kinds of scripting and embeddability featuresprovidedby Tcl andPerl can be extendedin an efficient manner to larger applications, while maintaining awell-defined standard(Common Lisp) for these extensions.In addition, the generality of Lisp makes Lisp agood candidate for an application-level communication language in distributed environments.

A toolkit for parallel functional programming

AbstractOur toolkit for the design and implementation of parallel functional programs supports the stepwise development of parallel programs from a high level sequential specification to an optimised parallel implementation. The toolkit is used as follows: The algorithm to be implemented is specified in a functional language. The program is debugged and tested using an interpreter. The program is compiled for a sequential machine. Its performance is analysed and improved. Annotation‐driven transformations are applied to the program to indicate parallel tasks. Simulations at task level, basic block level and bus transaction level make it possible to analyse the parallel performance of the program at three levels of detail. When the performance is optimised using the simulators, the program is executed on a genuine parallel machine. Several programs have been developed with the toolkit. A program that simulates tidal flow in an estuary of the North sea is presented as a case study to demonstrate the merits of the toolkit when developing complex parallel programs.The toolkit not only supports the design of parallel applications, it also allows the study of important concepts in parallel computer architecture. These include the behaviour of cached memory systems, bus protocols, scheduling algorithms and memory management algorithms.

Mission critical operating systems

Part 1 Operating system design concept: the StarLite operating system choices for mission critical computing operating system correctness is a mission critical requirement the ISIS distributed programming toolkit and the meta distributed operating system - a brief overview the structure of the clouds distributed operating system operating system constructs for managing real-time software complexity. Part 2 Real-time operating system: V - a foundation for mission critical distributed systems MARUTI - an environment for hard real-time applications the spring kernel the ARTS kernel - toward predicatable distributed real-time systems DRAGON SLAYER/MELODY - a highly adaptive distributed operating system for mission critical computing a real-time operating system for HARTS imprecise computations SDEX/44 and 43RSS - navy standard operating systems the kernel computational model of the alpha real-time distributed OS the distributed iRMX operating system - a real-time distributed operating system. Part 3 ADA-based real-time systems: understanding ada runtime environments real-time scheduling theory and ada an overview of DARK.

Event reconstruction in high-energy physics

Cooperative Processes Software (CPS), a parallel programming toolkit developed at Fermilab for processing CPU-intensive experimental data in the area of high-energy physics, is described. CPS allows physicists to solve computationally intensive problems on a collection of reduced-instruction-set-computer (RISC) workstations that work in parallel to provide solutions within a reasonable time frame. This mode of parallel processing provides a cost effective and easily scalable solution to CPU-bound computational problems that can be classified as large grained and loosely coupled. The performance of CPS on a typical experiment of Fermilab, which has 1000 to 2000 8 mm tapes of raw event data that needs to be reconstructed, is discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The ISIS project

The ISIS project has developed a distributed programming toolkit and a collection of higher level applications based on these tools. ISIS is now in use at more than 300 locations world-wise. The lessons (and surprises) gained from this experience with the real world are discussed.

A tool kit for database programming in Ada

This paper describes an Ada-compatible database application development environment being designed and prototyped at Computer Corporation of America. This environment is intended to provide uniform access to centralized, homogeneously distributed, and heterogeneously distributed databases. There are two key interfaces: an interactive interface called Daplex which is based on a semantically rich data model and a powerful access language, and an application program interface called Adaplex which consists of an expression level integration of Daplex with Ada. The objective of this paper is to explain our rationale for designing Adaplex and to describe its support environment.