Distributed Virtual System (DIVIRS) Project

As outlined in our continuation proposal 92-ISI-50R (revised) on contract NCC 2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to program parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the virtual system model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed

DIstributed VIRtual System (DIVIRS) project

As outlined in our continuation proposal 92-ISI-50R (revised) on NASA cooperative agreement NCC2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to develop and execute parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the Virtual System Model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed

DIstributed VIRtual System (DIVIRS) Project

The development of Prospero moved from the University of Washington to ISI and several new versions of the software were released from ISI during the contract period. Changes in the first release from ISI included bug fixes and extensions to support the needs of specific users. Among these changes was a new option to directory queries that allows attributes to be returned for all files in a directory together with the directory listing. This change greatly improves the performance of their server and reduces the number of packets sent across their trans-pacific connection to the rest of the internet. Several new access method were added to the Prospero file method. The Prospero Data Access Protocol was designed, to support secure retrieval of data from systems running Prospero

Coaches' learning and sustainability in high performance sport

In undertaking their complicated and multi-faceted work, high performance coaches have previously been shown to be influential in the performance of athletes. It has also been noted that high performance coaches are learners by necessity. However, what remains unclear is how coaches' learning influences their engagement in sustainable practice. This study draws on three cohorts of full-time high performance coaches employed in Olympic and professional sports throughout Australia. Semi-structured interviews were conducted face-to-face and were inductively analysed. The results revealed that the coaches were presented with a variety of opportunities to learn, with the most valued sources being 'learning on the job', 'discussions with others' and 'experience as athletes'. These unmediated learning opportunities are critiqued along with other mediated opportunities in relation to notions of sustainability. The dominance of unmediated sources of learning meant that sustainable practice was present but was not assured. Sustainable practice is also discussed in relation to the dominant models of high performance athlete development and the demands of coaching work

Prospero: A Tool for Organizing Internet Resources

Recent growth of the Internet has greatly increased the amount of information that is accessible and the number of resources that are available to users. To exploit this growth, it must be possible for users to find the information and resources they need. Existing techniques for organizing systems have evolved from those used on centralized systems, but these techniques are inadequate for organizing information on a global scale. This article describes Prospero, a distributed file system based on the Virtual System Model. Prospero provides tools to help users organize Internet resources. These tools allow users to construct customized views of available resources, while taking advantage of the structure imposed by others. Prospero provides a framework that can tie together various indexing services producing the fabric upon which resource discovery techniques can be applied

The Prospero File System: A Global File System Based on the Virtual System Model

Distributed file systems have come into widespread use in recent years. Many allow files to be accessed over large geographic areas and across organizational boundaries. However, few systems to date have given much thought to how information should be organized in such a global environment. This paper describes the Prospero File System, a file system based on the Virtual System Model, a model for building large systems within which users construct their own virtual systems by selecting and organizing the objects and services of interest. This customized view of a globaJ file system makes it easier for users to keep track of files that they have identified as being of interest. The use of multiple name spaces can cause confusion. Such confusion is eliminated by support for closure: ever) ' object has an associated name space, and names specified by the object are resolved in that name space. Tools are provided to allow views to be kept up-to-date, and to allow views to be defined as functions of other (possibly changing) views. These tools promote sharing and enable the organization of files in ways that make it easier to identify information of interest than it is in existing systems. The prototype implementation has been used to organize information available from Internet archive sites; its directory service has been used from more than 7,500 systems in 29 countries. This paper discusses the goals of the Prospero File System, describes the prototype implementation, and discusses experience with the use of the system to date