A programming Methodology for Disconnected Operation

: State-of-the-art mobile computing devices offer substantial storage capacity and computing power. The recent emergence of sophisticated wireless communication technology will transform these mobile computing devices into mobile communicators, creating a new genre of powerful hand-held computing devices that can take advantage of distributed systems technology and applications. However, either to conserve battery power, or to reduce cost these new communication devices will inherently need to disconnect from the network. If the disconnection occurs during the execution of a distributed computation, then the computation may need to suspend until reconnecting to the network This paper presents a programming methodology that enables the programmer to write applications capable of adapting to disconnected operation. Our approach is based on experience building a disconnected NFS filesystem (D-NFS) for portable computers. 1 Introduction This paper describes a programming methodology for ..

An Extensible Protocol Architecture for Application-Specific Networking

Plexus is a networking architecture that allows applications to achieve high performance with customized protocols. Application-specific protocols are written in a typesafe language and installed dynamically into the operating system kernel. Because these protocols execute within the kernel, they can access the network interface and other operating system services with low overhead. Protocols implemented with Plexus outperform equivalent protocols implemented on conventional monolithic systems. Plexus runs in the context of the SPIN extensible operating system. 1 Introduction This paper describes the design and implementation of Plexus, a protocol architecture that allows arbitrary applications to define application-specific protocols. Plexus allows protocol processing to be tailored using application-level knowledge, thus providing the framework for supporting new protocols [CSZ92], and implementing optimizations to existing protocols such as integrated layer processing and applica..

Region Analysis: A Parallel Elimination Method for Data Flow Analysis

Parallel data flow analysis methods offer the promise of calculating detailed semantic information about a program at compile-time more efficiently than sequential techniques. Previous work on parallel elimination methods [1, 2] has been hampered by the lack of control over interval size; this can prohibit effective parallel execution of these methods. To overcome this problem, we have designed the region analysis method, a new elimination method for data flow analysis. Region analysis emphasizes flow graph partitioning to enable better load balancing in a more effective parallel algorithm. In this paper, we present the design of region analysis and the empirical results we have obtained that indicate (1) the prevalence of large intervals in flow graphs derived from real programs, and (2) the performance improvement of region analysis over parallel Allen-Cocke interval analysis. Our implementation analyzed programs from the Perfect Benchmarks [3] and netlib [4] running on a Sequent Sym..