Robert Firth's research while affiliated with Carnegie Mellon University and other places

This document defines the functionality of the Distributed Ada Real-Time Kernel (hereafter called the Kernel). The Kernel is being developed as one artifact of the Distributed Ada Real-Time Kernel Project (hereafter called the project). The goal of the Kernel is to support effectively the execution of the distributed Ada applications in an embedded computer environment. The Kernel provides use's with support for language functionality (i.e., the ability to execute Ada programs in a distributed, real-time environment); it does not provide support for language features (i.e., Ada tasking primitives). As a result, the Kernel specification places certain requirements (restrictions and conventions) on the Ada application programs that use the Kernel. These will become apparent to the reader as the definition of the Kernel is expounded. This document is divided into three parts: (1) Kernel Background: describes the models on which the Kernel is based and outlines the scope of its capabilities; (2) Requirements: describes the functionality and performance required of the Kernel; and (3) Kernel Primitives: describes the mechanisms and primitive capabilities the Kernel provides to implement the requirements. (kr)

This document characterizes a specific version of the Distributed Ada Real-Time Kernel (DARK) software artifact and supplies documentation for its installation and use. This document is geared toward: the engineer responsible for installing the Kernal, engineers responsible for proting and maintaining the Kernel, and engineers using the Kernel and needing an awareness of changes from the previous release. Keywords: Ada< DARK, Distributed, Kernel, Operating systems, Real-time.

This document contains the detailed description of the Kernel. The overall system architecture and the rationale for it are presented as relevant to both the application (i.e., the external view of the Kernel) and the Kernel maintainer (i.e., the internal view of the Kernel). This document presents the algorithms and data structures needed to implement the functionality defined in the Kernel Facilities Definition. This document also contains an in-depth description for the communication protocol used by the Kernel, both the network software and hardware that compose the DARK testbed at the SEI, and a detailed enumeration of all compiler dependencies exploited by Kernel software. This document is geared toward engineers responsible for porting and maintaining the Kernel and engineers requiring detailed information about the internals of the Kernel.

This document contains detailed descriptions of various computer program packages. Keywords: Ada, Computer networks, Configurations, Interfaces.

This document describes the modifications made to the Distributed Ada Real-Time Kernel (DARK) software when porting it from its original execution environment, the 68020-based testbed built at the Software Engineering Institute, to a VAX/VMS system. This document also contains information about logical extensions to the Kernel, and the impacts thereof, should the Kernel be used in operational systems. Ada, DARK, Distributed, Kernel, Operating system, Real-time.

Ada is now being mandated for a large number of DoD development projects as the sole programming language to be used for developing software. Many of these projects are trying to build distributed real-time systems. Many project managers and contractors are anxious to support this effort, to reap the advantages of Ada, and to use the newer techniques of software engineering that Ada can support. This transition, however, has not always been smooth; some serious problems have been encountered. This paper discusses several of thes e problems and describes a prototype software artifact, called the Distributed Ada Real-Time Kernel (DARK), built to address these concerns and to support execution of real-time Ada applications in a distributed, embedded environment. This prototype is not intended to solve all the problems of real-time, embedded systems, but it does provide one viable, near-term option demonstrating that Ada can be used in real-time systems today.

This manual describes the models underlying the Kernel and its concept of operations, presents the primitives available to the application program, and provides a number of abstractions that may readily be built on top of Kernel primitives. The Kernel is a body of code that implements real-time facilities which can be invoked by applications written in Ada for execution on a distributed target. The requirements for the Kernel, both behavior and performance, are provided in the Kernel Facilities Definition, and its design will be provided in the forthcoming Kernel Architecture Model. The Kernel was built at the Software Engineering Institute by the Distributed Ada Real-Time Kernel (DARK) Project. Ada is now being mandated for a large number of DoD development projects as the sole programming language to be used for developing software. Many of these projects are trying to build distributed real-time systems. Many project managers and contractors are anxious to support this effort, to reap the advantages of Ada, and to use the newer techniques of software engineering that Ada can support. This tradition, however has not always been smooth; some serious problems have been encountered.

Defines the conceptual design of the Kernel by specifying: ? The underlying models, assumptions, and restrictions that govern the design and implementation of the Kernel; and ? The behavioral and performance requirements to which the Kernel is built. This document is the requirements and top level design document for the Kernel.