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Durra is a language and support environment for the specification and execution of distributed Ada applications. The Durra programmer specifies the distribution of application components by assigning them to virtual nodes called clusters. For each cluster named in an application description the Durra compiler generates an Ada package body with a standardized format. Within the confines of the format, the content of the package body varies according to the requirements placed upon the cluster by the Durra application description. The cluster-specific package body is compiled and linked with a fixed set of Ada compilation units, common to all clusters, to form a multitasking Ada program. The intended audience for this document is Durra application developers, who will need an understanding of the concepts presented here in order to be effective Durra application debuggers. Code generation, Distributed processing, Configuration management, Task-description languages, Distributed processing.

Durra is a language and support environment for the specification and execution of distributed Ada applications. A Durra programmer describes an application as a collection of processes and data links. More complicated application descriptions may also include a structuring of this collection that varies dynamically according to a set of reconsideration conditions. Each process defined in the application description is associated with an independently complied Ada subprogram that implements the behavior of that process. The Durra programmer specifies the distribution of application components by assigning them to virtual nodes called clusters. For each cluster, the Durra compiler generates a multithreaded Ada program that imports the code for the processes assigned to that node and manages their execution. Durra also facilitates rapid prototyping through the use of tools that interpret timing specifications associated with processes and generates Ada code to simulate their expected behavior.

Durra is a language designed to support PMS-level programming. PMS stands for Processor-Memory-Switch, the name of the highest level in th hierarchy of digital systems. An application or PMS-level program is written in Durra as a set of task descriptions and type declarations that prescribes a way to manage the resources of a heterogeneous machine network. The application describes the tasks to be instantiated and executed as concurrent processes. The types of data to be exchanged by the processes, and the intermediate queues required to store the data as they move from producer to consumer processes. The report describes the Durra Runtime Environment. The environment consists of three active components: the application tasks, the Durra server, and the Durra scheduler. After compiling the type declarations, the component task descriptions, and the application description, the application can be executed by starting an instance of the server on each processor, starting an instance of the scheduler on one of the processors, and downloading the component task implementations (i.e., the programs) to the processors. the scheduler receives an an argument the name of the file containing the scheduler program generated by the compilation of the application description. This step initiates the execution of the application., Sponsored in part by the DoD.

Durra is a language designed to support the construction of distributed applications using concurrent, coarse-grain tasks running on networks of heterogeneous processors. An application written in Durra describes the tasks to be instantiated and executed as concurrent processes, the types of data to be exchanged by the processes, and the intermediate queues required to store the data as they move from producer to consumer processes. This report describes an experiment in writing task descriptions and type declarations for a subset of the Generalized Image Library, a collection of computer programs developed at the Department of Computer Science at Carnegie Mellon University. The experiment illustrates the development of a typical Durra application. This is a three step process: first, a collection of tasks (programs) is designed and implemented (these are the GIL programs); second, a collection of task descriptions corresponding to the task implementations is written in Durra, compiled, and stored in a library; and finally, an application description is written in Durra and compiled, resulting in a set of resource allocation and scheduling commands to be interpreted at runtime. A few sample application descriptions were developed as part of the experiment and are also reported in this document. Keywords: Real time; Computer networks., Sponsored in part by the DoD.

Durra is a language designed to support the construction of distributed applications using concurrent, coarse-grain tasks running on networks of heterogeneous processors. An application written in Durra describes the tasks to be instantiated and executed as concurrent processes, the types of data to be exchanged by the processes, and the intermediate queues required to store the data as they move from producer to consumer processes. This report describes an experiment in implementing a command, control, communications and intelligence (C3I) node using reusable components. The experiment involves writing task descriptions and type declarations for a subset of the TRW testbed, a collection of C3I software modules developed by TRW Defense Systems Group. The experiment illustrates the developed of a typical Durra application. This is a three-step process: first, a collection of tasks (programs) is designed and implemented (these are the testbed programs); second, a collection of task descriptions corresponding to the task implementations is written in Durra, compiled, and stored in a library; and finally, an application description is written in Durra and compiled, resulting in a set of resource allocation and scheduling commands to be interpreted at runtime. This report illustrates the methodology for building complex, distributed systems supported by Durra. Keywords: Programming languages.

Durra is a language designed to support the development of large- grained parallel programming applications. This is the manual for users of the Durra compiler, runtime system, and support tools. Additional documents that describe the syntax and semantics of the language and the runtime environment are cited in the bibliography section.

Durra is a language designed to support the construction of distributed applications using concurrent, coarse-grained tasks running on networks of heterogeneous processors. An application written in Durra describes the tasks to be instantiated and executed as concurrent processes, the types of data to be exchanged by the processes, and the intermediate queues required to store the data as they move from producer to consumer processes. This report describes the Durra application debugger/monitor, a program that works in conjunction with the Durra runtime software to help the developer locate errors and/or performance bottlenecks in a Durra application.