Jim Gast's Selected Publications

Supported by the Anthony C. Klug NCR Fellowship in Computer Science

On-Line Talks

• Various on-line talks during CS-740. CS-740 is the seminar course for Advanced Topics in Networking at University of Wisconsin / Madison. I taught the course and led half of the discussions. Each student led one discussion. The CS-740 talks web page contains pointers to the on-line talks, including an introduction by me. The Main CS-740 Web Page contains related information about the course and the papers discussed.

Internet Backbone

• Representing the Internet as a Succinct Forest in IEEE Networks, March, 2004. Vol 45/1. Combining previous techniques for inferring the structure of the Internet ISP connections, this paper creates an acyclic tree that can be used for Internet size and Internet growth estimation. A practical use for solving cache placement problems is presented. Available in PDF.
• Topology Aware Estimation Methods for Internet Traffic Characteristics Ph.D. Thesis, August, 2003. Presents a model for analyzing aggregate traffic at one edge of Internet 2 to infer congestion in the backbone based on one-way delay experiments from the Surveyor project. The nature of harmonic congestion propagation is explored and measurements are proposed that can be used to inform future growth. Available in PDF and Postscript.
• Cache Placement Methods Based on Client Demand Clustering. This Technical Report (workshop version in HTML or full version PS) presents a method for optimal placement of proxy caches and web services in the Internet. Placing redundant services like Content Distribution Networks close to clients improves performance from the client perspective. The paper uses information from Border Gateway Protocol to derive a forest of trees that represent the major branches of the Internet. Client demand from web server logs is aggregated and a dynamic programming algorithm identifies optimal points in the trees for service placement.
• Resource Deployment based on Autonomous System Clustering. This conference paper has been accepted for Global Internet 2002, Taiwan, Nov. 2002. It presents algorithms for annotating and augmenting an Internet Topology representation to combine BGP tables with traceroute results. The resultant AS forest is a compact representation of the Internet that has better prediction capabilities. Available in PDF or Postscript.
• Internet Congestion Characteristics and Implications, This document was my prelim paper and slides to present my research agenda to my thesis committee. It poses the basic questions of tracking, graphing, and ultimately understanding how congestion affects traffic flow in the Internet. In particular, what does a congestion event look like? Does congestion propagate to neighboring links? How can we visualize global Internet congestion in a meaningful way in near-real-time? Since the prelim document is a research proposal, it asks more questions than it answers, but even the questions are thought-provoking. How would you build a lab that could emulate the Internet backbone? Even if you knew the parameters, how would you validate that the parameters used in the model legitimately reflect the values seen in the real backbone?

Tape and Removable Storage

• Sample article from Computer Systems Review, March, 1991. This particular article was one of the few to survive. It describes the Fault Tolerance used in 8mm tapes and shows how tapes after 1992 can hold far more data than prior technologies.
• SIDF

Architecture

• RunAhead. Slides for a talk on predicting the future disk reads of processes. The proposed technique uses speculative threads to run ahead of the real thread of execution.
• Using Priority to Increase Throughput of Explicitly Parallel Applications. Proposes techniques for prioritization of threads in Simultaneous Multi-Threaded processors. This was a student paper presented in CS-752.

Distance Learning

• Global Collaboration for a Joint University Course on the Next Generation Internet presented at INET 2000. The paper covers an experiment done during the fall semester, 1999 in which Computer Science 640 was shared between Japan and Wisconsin via full-motion video in real time. See Joint lectures with Japan for more information..
  The full semester of lectures are archived at the Japanese site.

Disk and File Servers

• Metrics to Use on the Road to Hierarchical Storage Management. A paper presented at IEEE CompCon, 1995. The paper presents a set of metrics for managing and maintaining a storage farm that includes both high and low latency storage. Simple metrics like "youngest file migrated" and "bytes of files de-migrated" are presented and explained. The paper concludes with ways to optimize future spending to tradeoff the utility of adding more on-line storage versus the utility of adding more bandwidth and capacity to robotically-available near-line capacity.
• Storage Networking Industry Association. This introduction was the talk given at the formation meeting September 5, 1997 in Provo, Utah. After welcoming the first 6 companies, the talk introduces the challenges and opportunities of an industry consortium based on moving proprietary interfaces into an open market and creating open standards where new ones are needed. Since then, the SNIA has grown to over 300 member companies.
• Impact of Distributed File Systems on Storage Management Services. A talk presented at Network Storage '96, May, 1996. This talk introduced the new concepts and APIs needed for backup, replication, and archiving in a multi-architecture environment. Replicas of files need to include extra metadata beyond simply the owner and permissions. Original files need to know about their protection status, backup files need to know if their original file has disappeared or changed, and replicas need to know how often to synch up.
• Managing Distributed Data on the Smart Global Network. A talk presented at Brainshare 1996, Salt Lake City, April, 1996. This talk was the first public peek at Novell's new NetWare Storage System and the changes that would be needed to take full advantage of some of the new features. This 64-bit file system erased limitations of the prior file system. Many of the existing third-party backup and archiving systems would automatically gain the benefits if they were correctly using the Storage Management Services APIs.
• Developing SMS Backup. A tutorial presented at Interop 1994, Atlanta, September, 1994. This tutorial introduced the concepts and APIs of Storage Management Services, a cross-platform architecture for preserving and restoring all of the data and metadata of files. Platform-dependent Target Service Agents translated metadata into System Independent Data Format. This work went on to become the first, new ISO standard tape and optical disk format in over a decade (ECMA-208 and ISO/IEC-14863). This tutorial also discussed the Universal Disk Format (UDF) which was later extended by the Optical Storage Technology Association and used as the disk format for all current DVDs.
• FileSys Presentation. Slides for my talk on the difference between kernel-level file servers and user-level file servers.
• Common file sequence prediction. This paper examines the sequence of file opens typically seen by programs like Microsoft Word. Dozens of DLLs and initialization files are opened in a sequence that could be easily optimized. File systems that recognize the onset of such sequences can accelerate the file opens in anticipation. (hardcopy only, I have to re-type it?!?)
• Talks on file replication via http to be added.

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