Ground Systems Development Environment (GSDE) interface requirements and prototyping plan

This report describes the data collection and requirements analysis effort of the Ground System Development Environment (GSDE) Interface Requirements study. It identifies potential problems in the interfaces among applications and processors in the heterogeneous systems that comprises the GSDE. It describes possible strategies for addressing those problems. It also identifies areas for further research and prototyping to demonstrate the capabilities and feasibility of those strategies and defines a plan for building the necessary software prototypes

Ground Systems Development Environment (GSDE) interface requirements analysis

A set of procedural and functional requirements are presented for the interface between software development environments and software integration and test systems used for space station ground systems software. The requirements focus on the need for centralized configuration management of software as it is transitioned from development to formal, target based testing. This concludes the GSDE Interface Requirements study. A summary is presented of findings concerning the interface itself, possible interface and prototyping directions for further study, and results of the investigation of the Cronus distributed applications environment

Acquisition of computer research equipment

Issued as Final report, Project no. G-36-61

Implementation of an activity coordinator for an activity-based distributed system

Distributed computing systems offer a number of potential benefits, including: - improved fault-tolerance and reliability - increased processor availability - faster response time - flexibility of system configuration - effective management of geographically distributed resources - integration of special purpose machines into applications In order to realize this potential, support systems that aid in the development of distributed programs are needed. An Activity System facilitates the design and implementation of distributed programs: (1) By allowing the programmer to group functionally related objects into an activity (or job) which is recorded within the system. The information stored concerning relationships between objects may then be used to control their interactions and thus to manage distributed resources. (2) By effectively eliminating the need for the programmer to deal with the underlying details of inter-process communication. The system handles the establishment of communication links between objects in an activity, and controls the routing of messages to activity members. To evaluate the uses of activities in developing distributed programs, I have implemented a portion of such a system; namely, an Activity Coordinator , together with Activity System components and test tools required to verify its functionality. Within the context of an Activity System, the Activity Coordinator provides certain key functions: (1) It maintains a database of information pertaining to objects and activities, and (2) It handles the routing of activity related messages. In future versions of the activity system the Activity Coordinator may also play a more active role in fault recovery. These possibilities will also be discussed

A hierarchical distributed control model for coordinating intelligent systems

A hierarchical distributed control (HDC) model for coordinating cooperative problem-solving among intelligent systems is described. The model was implemented using SOCIAL, an innovative object-oriented tool for integrating heterogeneous, distributed software systems. SOCIAL embeds applications in 'wrapper' objects called Agents, which supply predefined capabilities for distributed communication, control, data specification, and translation. The HDC model is realized in SOCIAL as a 'Manager'Agent that coordinates interactions among application Agents. The HDC Manager: indexes the capabilities of application Agents; routes request messages to suitable server Agents; and stores results in a commonly accessible 'Bulletin-Board'. This centralized control model is illustrated in a fault diagnosis application for launch operations support of the Space Shuttle fleet at NASA, Kennedy Space Center

Literature Review For Networking And Communication Technology

Report documents the results of a literature search performed in the area of networking and communication technology

Fault tolerance distributed computing

Issued as Funds expenditure reports [nos. 1-4], Quarterly progress reports [nos. 1-3], and Final report, Project no. G-36-63