GOST: Global Operating System Technologies

University of Southern California
Information Sciences Institute

Faculty and Staff

• B. Clifford Neuman(Group Leader)
• Brian Tung
• Dongho Kim
• Tatyana Ryutov

Former Faculty and Staff

• Steven Augart
• Sridhar Gullapalli
• Padma Haldar
• John Heidemann
• Katia Obraczka
• Nader Salehi
• Gene Tsudik
• Diana Ehrlich
• Rebecca Jordan

Students graduated with the Ph.D.

• Sukumal Imudom
• Dongho Kim
• Konstadinos Kutsikos
• Ari Gennady Medvinsky
• Santosh Rao
• Sung-Wook Ryu
• Tatyana Ryutov
• Brenda Timmerman

Former Students

• Kemal Bicakci
• Sio-Man Cheang
• Ho Chung
• Grig Gheorghiu
• Eul Gyu Im
• Wen-Hui Gao
• Charlie Lai
• Prasad Upasani
• Elliot Yan

Project Goals

Technical Approach and Project Innovations

Transitive indexing allows users and applications to locate files and objects across the network by building indices for hierarchical information based on attributes from the current node and summaries from other indices. Transitive indexing is designed to be scalable in an environment lacking centralized administrative control.

The Prospero File Access Protocol (PFAP) enables the hierarchical caching and retrieval of bulk data across the Internet. PFAP provides a single uniform interface to multiple caching mechanisms including whole file caching and block caching depending on the reference characteristics of the data and the requirements of clients and servers. PFAP has been integrated with security and payment mechanisms to support controlled access to data objects with restricted access policies.

The GOST project has developed a new efficient garbage collection algorithm for distributed systems using the propagation of last referencable time and registration of links. Garbage collection allows the reclamation of storage for objects which are no longer needed. Support for link maintenance has been developed as part of the garbage collection algorithm, allowing the update of references to objects that have moved across nodes.

Through the work of the GOST project on replication, multiple replication methods and associated consistency algorithms are supported. The specific method to be used may be specified at the granularity of individual objects, files, or directories based on the characteristics and requirements of the individual object, file, or directory. Where existing methods do not meet the needs of an object, application specific methods may be inserted into and are supported by the GOST framework for replication.

The PDS provides a common access protocol through which applications and middleware can retrieve and modify directory information and object attributes. The present implementation of the PDS provides gateways to existing applications such as WWW, FTP, Prospero Mail and a web management tool.

In the area of parallel processing, the GOST project is developing tools that provide support for fault-tolerant and real-time distributed and parallel applications under the Prospero Resource Manager (PRM). Efforts include debugging, compilation, reconfiguration and performance tools that simplify the development of parallel applications, providing support for running sequential applications without re-compilation, improving the communication libraries used by parallel applications and, improving remote I/O performance.

Project Accomplishments (upto July 1998)

• A multi-threaded version of the ARDP (a secure, lightweight transport protocol) client library has been designed and implemented. The new library has been integrated with Prospero, and it enables multiple threads within a client process to access Prospero server(s) simultaneously, without waiting for other threads' requests to complete.

• A new secure version of ARDP transport protocol has been designed and developed. ARDP is a lightweight, reliable request-response type transport protocol. The built-in security context now enables the protocol to provide secure client-server communications. The functionality includes data privacy and integrity functions, such as Kerberos-based encryption, authentication, and integrity. Development on ARDP spans DARPA funded GOST, SOAP and SILDS projects.

• A new tool managing web services called the Prospero Web Management System has been developed. It enables authorized users controlled access to view and modify contents and properties of distributed data objects. It also provides security and reliability services. The implementation is multi-threaded providing high-performance access to managed data.

• A new Prospero based e-mail system allows users to access e-mail messages from multiple mailboxes, across different administrative domains in a location transparent manner. This system reduces storage requirements by enabling sharing of copies of messages sent to a group of users, and reduces network traffic by deferring delivery of the actual content of a message to each recipient. The middleware services integrated with the PDS are used by the e-mail system to control access to, search for, replicate messages, and to support disconnected operation. The Prospero Mail system is being provided as an Application Programming Interface (API) to enable application developers to build applications on top of this framework.

• A new, efficient garbage collection algorithm for distributed computing environment has been developed. Garbage collection is the mechanism that allows the reclamation of storage for objects which are no longer needed. Garbage collection in distributed systems is difficult to implement because objects are under the control of many organizations, not all of whom operate under the same rules and policies. The algorithm developed is especially suitable for web-like information spaces, where only loose control over the participating systems exists.

Technical Plan for the coming year (1998-99)

• Development of compilation and configuration tools that automatically generate configuration information for parallel applications, and store this information in the PDS.
• Provision of support for fault-tolerant and real-time applications. Software supporting such applications will be released and deployed as part of the Prospero Resource Manager (PRM) environment.

• Extensions will be designed that will enable peer-to-peer access to disconnected objects when peers are disconnected from central nodes, but able to share cached or pre-staged data. To the extent practical given funding constraints, these extensions will be implemented for the Prospero mail messaging system. Ultimately we would like to support this functionality to support complete "drop-in" information infrastructure.
• New versions of our secure ARDP transport protocol (Version 1.1) and the Prospero Directory Service (Version 5.5) will be released for deployment.

Technology Transition

Technology will be transferred through channels that have already been established as part of previous work on the Prospero Directory Service, and the Prospero Resource Manager. Prior releases of PDS have been distributed widely, and it has been used as an embedded service by applications running from more than 100,000 systems on the Internet. Stand-alone modules for incorporation with application are available, allowing the resulting extensions to be used by others.

We have been working with a venture capital firm, Media Technology Ventures to transfer Prospero technology to a startup firm, Brevity Technology, which is designing a meta-directory product around Prospero that will integrate information from multiple legacy systems.

We have also been in discussions with Rendezvous Software, of Palo Alto, California. Rendezvous intends to use the Prospero Directory Service as part of a new product; the details of this product are currently protected by a Non-Disclosure Agreement.