Decentralizing UNIX abstractions in the exokernel architecture

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 49-51).by Héctor Manuel Briceño Pulido.M.Eng

Asynchronous event handing

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 55-56).by Sandeep Chatterjee.M.S

Sampling benchmarks : methods for extracting intersecting segments of programs

Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (leaves 46-49).by Peter D. Finch.S.B.and M.Eng

The influence of protocol choice on network performance

Bibliography: leaves 100-102.Computer communication networks are a vital link in providing many of the services that we use daily, and our reliance on these networks is on the increase. The growing use of networks is driving network design towards greater performance. The greater need for network connectivity and increased performance makes the study of network performance constraints important. Networks consist of both hardware and software components. Currently great advances are being made in network hardware, resulting in advances in the available raw network performance. In this thesis, I will show through measurement that it is difficult to harness all the raw performance and to make it available to carry network services. I will also identify some of the factors limiting the full utilization of a high speed network

Flexible and efficient sharing of protected abstractions

Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 73-76).by George M. Candea.S.B.and M.Eng

Design and implementation of XML-based Linux file system runner

This thesis presents the design and implementation of XML_based Linux File System Runner (XML_LFS), a file system simulator that integrates the representation ability of Extensible Markup Language (XML) with the beauty of Linux file system architecture. XML_LFS uses a layered approach to design a generic file system runner from scratch utilizing Java programming language and JDOM. The hierarchical directory structure of the file system is kept in an XML file for easy manipulation as well as on disk for crash recovery. UNIX-like file systems such as the Second Extended File System (Ext2), a native mini file system (mini3fs) and Linux kernel codes for file system operations are explored for the real implementation work.;Traditional file system consists of a hierarchical tree, composed of directories and files. Each directory can contain both files and subdirectories. This is an equivalent concept to semi-structured elements in XML. Embedding an XML log file layer into the Linux file system architecture can speed up the directory look up by combining the power of XML and XQuery as well as eliminating the limitations of the existing fixed-attribute file system model by treating files as elements to a customizable XML document. Thus, the whole development environment is more useful for future file system research. The future of XML file system is discussed in detail. Complete system architecture and functionalities are built and the process is described in the thesis. Initial Bonnie-like and Andrew-like benchmarks of the prototype implementation show that XML_LFS achieves the expected performance results

Title of Dissertation: Supporting Distributed Multimedia Applications on ATM Networks

ATM offers a number of features, such as high-bandwidth, and provision for per-connection quality of service guarantees, making it particularly attractive to multimedia applications. Unfortunately, the bandwidth available at ATM's data-link layer is not visible to the applications due to operating system (OS) bottlenecks at the host-network interface. Similarly, the promise of per-connection service guarantees is still elusive due to the lack of appropriate traffic control mechanisms. In this dissertation, we investigate both of these problems, taking multimedia applications as examples. The OS bottlenecks are not limited to the network interfaces, but affect the performance of the entire I/O subsystem. We propose to alleviate OS's I/O bottleneck by according more autonomy to I/O devices and by using a connection oriented framework for I/O transfers. We present experimental results on a video conferencing testbed demonstrating the tremendous performance impact of the proposed I/O architecture on networked multimedia applications. To address the problem of quality of service support in ATM networks, we propose a simple cell scheduling mechanism, named carry-over round robin (CORR). Using analytical techniques, we analyze the delay performance of CORR scheduling. Besides providing guarantees on delay, CORR is also fair in distributing the excess bandwidth. We show that albeit its simplicity, CORR is very competitive with other more complex schemes both in terms of delay performance and fairness. (Also cross-referenced as UMIACS-TR-95-88

The design and implementation of a prototype exokernel operating system

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 99-106).by Dawson R. Engler.M.S

Robust services in dynamic systems

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 191-202).Our growing reliance on online services accessible on the Internet demands highly- available systems that work correctly without interruption. This thesis extends previous work on Byzantine-fault-tolerant replication to meet the new requirements of current Internet services: scalability and the ability to reconfigure the service automatically in the presence of a changing system membership. Our solution addresses two important problems that appear in dynamic replicated services: First, we present a membership service that provides servers and clients in the system with a sequence of consistent views of the system membership (i.e., the set of currently available servers). The membership service is designed to be scalable, and to handle membership changes mostly automatically. Furthermore, the membership service is itself reconfigurable, and tolerates arbitrary faults of a subset of the servers that are implementing it at any instant. The second part of our solution is a generic methodology for transforming replicated services that assume a fixed membership into services that support a dynamic system membership. The methodology uses the output from the membership service to decide when to reconfigure.(cont.) We built two example services using this methodology: a dynamic Byzantine quorum system that supports read and write operations, and a dynamic Byzantine state machine replication system that supports any deterministic service. The final contribution of this thesis is an analytic study that points out an obstacle to the deployment of replicated services based on a dynamic membership. The basic problem is that maintaining redundancy levels for the service state as servers join and leave the system is costly in terms of network bandwidth. To evaluate how dynamic the system membership can be, we developed a model for the cost of state maintenance in dynamic replicated services, and we use measured values from real-world traces to determine possible values for the parameters of the model. We conclude that certain deployments (like a volunteer-based system) are incompatible with the goals of large- scale reliable services. We implemented the membership service and the two example services. Our performance results show that the membership service is scalable, and our replicated services perform well, even during reconfigurations.by Rodrigo Seromenho Miragaia Rodrigues.Ph.D