Office: 2212 VTKW-2

Office hours: TBD and by appointment

Phone: 540-231-3046

Email: gback@cs.vt.edu

The best way to contact me is by email, but it's okay to drop by anytime my door is open. Send me email if you want to make sure I am there.

Here's my Google calendar - (access may require a Google account)

Current Students

I am looking for both MS and PhD students. If you are interested in doing research in systems at any level of the software stack, from middleware to hypervisor, send me an email!

MS:

• Andrew Phelps
  

I am also advising a number of undergraduate students in undergraduate research projects.

Past Students

Ruslan Nikolaev. PhD, 2013. previously at Microsoft, Inc. and Pure Storage, now Virginia Tech
Dissertation: Design and Implementation of the VirtuOS Operating System

Mehmet Belgin. PhD, 2010. now at Georgia Tech, Academic & Research Technologies
Dissertation: Structure-based Optimizations for Sparse Matrix-Vector Multiply (co-advised with Dr. Ribbens)

Shahrooz Feizabadi. PhD, 2006.
Dissertation: Garbage Collection Scheduling for Utility Accrual Real-Time Systems

Eric Williamson MS, 2018. now at Facebook, Inc.
Thesis: Hybrid Analysis Tools for Computer Systems Education

William Naciri MS, 2017. now at Verisign, Inc.
Thesis: Bug Finding Methods for Multithreaded Student Programming Projects

Lance Chao MS, 2016. now at Facebook, Inc.
Thesis: Symmetric MultiProcessing for the Pintos Instructional Operating System

Xiaozhong Pan MS, 2015. now at Amazon, Inc.
Thesis: Rich Cloud-based Web Applications with Cloudbrowser 2.0

Sushrut Shirole MS, 2014. now at Cisco
Thesis: Performance Optimizations for Isolated Driver Domains

Sony Vijay MS, 2013. now at Bank of America/Merrill Lynch
Thesis: The LibX LibApp Builder

Brian McDaniel MS, 2012. now at Rackspace
Thesis: The CloudBrowser Web Application Framework

Brian Nicholson MS, 2011. now at Mozilla Foundation
Thesis: LibX 2.0

Mike Woods (Co-advised with Dr. Edwards), MS, 2011. now at Cisco
Thesis: CloudSpace: A Web Development Environment for CS1 Courses

Amarjyoti Deka MS, 2010. now at Microsoft, previously at Acision Inc.
Thesis: ScriptSpaces: An Isolation Abstraction for Web Browsers

Tilottama Gaat MS, 2008. now at Rackspace Hosting.
Thesis: The LibX Edition Builder

Jaishankar Sundaramanan MS, 2008. now at Google.
Thesis: HDPV: Highly Interactive, Faithful, In-Vivo Runtime State Visualization for Software Programs

Nathan Baker. MS, 2007. now at NetApp, Inc.
Thesis: LibX IE: An Internet Explorer Add-On for Direct Library Access

Abhijit Deodhar. MS, 2007. now at NetApp, Inc.
Thesis: COPS: A Framework for Consumer Oriented Proportional share Scheduling

Vijay Kumar Muthukumaraswamy Sivakumar. MS, 2007. now at Microsoft.
Thesis: An Evaluation of the Linux Virtual Memory Manager to Determine Suitability for Runtime Variation of Memory

Prasad Gopal. MS, 2006. now at Google.
Thesis: Top: An Infrastructure for detecting Application-Specific Program Errors by Binary Runtime Instrumentation

Veena Basavaraj. MS, 2006. now at LinkedIn
Thesis: Optimality of Heuristic Schedulers in Utility Accrual Real-time Scheduling Environments

Research Interests

My current research interests lie in a variety of areas related to computer systems.

Current Research

I am always looking for good students that are interested in all aspects of software systems. My current research focuses on the development of new execution environments for cloud (e.g. web) applications, both client and server-side.

Past research involves dynamic runtime checking, static analysis on the programming language side, and real-time scheduling, garbage collection, memory management, network simulation, and parallel programming on the OS side.

Major ongoing research efforts include

VirtuOS. For an overview, see our SOSP 2013 paper.

CloudBrowser. For an overview, see our SPLASH/Wavefront 2012 paper.

LibX. For an overview, see this talk.

Top and HDPV. See this paper for an overview.

Enhance Thyself - automatic program enhancement. See this paper for an overview.

Virtualization for High-End Computing.

Past Research

• MJ: I developed MJ, a system which applies meta-level compilation techniques to Java. We have used meta-level compilation as a static analysis tool for finding bugs in large software systems. It found thousands of bugs in the Linux kernel, for instance.

  Of course, in a system written in a weakly-typed language such as C, bugs are a dime a dozen. The challenge in MJ is to apply meta-level compilation to a type-safe language from which simple bugs, such as dangling pointers, have already been eliminated.

• KaffeOS: Single-language runtime systems, in the form of Java virtual machines, are widely deployed platforms for executing untrusted mobile code. These runtimes provide some of the features that operating systems provide: inter-application memory protection and basic system services. They do not, however, provide the ability to isolate applications from each other, or limit their resource consumption. KaffeOS is a Java runtime system that provides these features. The KaffeOS architecture takes many lessons from operating system design, such as the use of a user/kernel boundary, and employs garbage collection techniques, such as write barriers. While KaffeOS has not been released, a successor project, JanosVM is available here.

• DataScript: DataScript is a language to describe and manipulate binary data formats as types. DataScript consists of two components: a constraint-based specification language that uses DataScript types to describe the physical layout of data and a language binding that provides a simple programming interface to script binary data. A DataScript compiler generates Java libraries that are linked with DataScript scripts. A release of the software is available at SourceForge.

• OSKit: The OSKit is a framework and a set of 34 component libraries oriented to operating systems, together with extensive documentation. By providing in a modular way not only most of the infrastructure "grunge" needed by an OS, but also many higher-level components, the project's goal is to lower the barrier to entry to OS R&D and to lower its costs. The OSKit makes it vastly easier to create a new OS, port an existing OS to the x86, or enhance an OS to support a wider range of devices, file system formats, executable formats, or network services. For language researchers and enthusiasts, the OSKit lets them concentrate on the real issues raised by using advanced languages inside operating systems, such as Java, Lisp, Scheme, or ML--- instead of spending six months or years groveling inside ugly code and hardware. The OSKit homepage.

• Kaffe: I was a contributor to the Kaffe project, an open source Java virtual machine.

This semester (Spring 2020)

CS 3214 - Computer Systems

Courses taught in the past:

• Spring 2018: CS 3214 - Computer Systems
• Spring 2016: CS 3214 - Computer Systems
• Fall 2015: CS 5204 - Operating Systems.
• Spring 2015: CS 4284 - Systems & Networking Capstone.
• Fall 2014: CS 3214 - Computer Systems
• Spring 2014: CS 6204 - Cloud Environments.
• Fall 2013: CS 5204 - Operating Systems.
• Spring 2013: CS 4284 - Systems & Networking Capstone.
• Fall 2012: CS 5204 - Operating Systems.
• Spring 2012: CS 5565 - Networking Architectures and Protocols.
• Fall 2011: CS 3214 - Computer Systems
• Spring 2011: CS 6204 - Advanced Topics Execution Environments for Cloud Applications
• Fall 2010: CS 3214 - Computer Systems
• Spring 2010: CS 3214 - Computer Systems
• Spring 2010: CS 1114 - Introduction to Software Design
• Fall 2009: CS 3214 - Computer Systems
• Spring 2009: CS 5565 - Networking Architecture and Protocols
• Fall 2008: CS 3204 - Operating Systems.
• Fall 2007: CS 3204 - Operating Systems.
• Fall 2007: CS 5204 - Operating Systems.
• Spring 2007: CS 3204 - Operating Systems.
• Fall 2006: CS 3204 - Operating Systems.
• Spring 2006: CS 3204 - Operating Systems.
• Spring 2006: CS 5565 - Networking Architecture and Protocols.
• Fall 2005: CS 5204 - Operating Systems
• Spring 2005: CS 5565 - Networking Architecture and Protocols.
• Fall 2004: CS 5204 - Operating Systems
• Fall 2002, Summer 2003: CS 143 - Compilers (at Stanford)

I've been Associate Professor at Virginia Tech since June 2010, having joined in 2004.

I worked as a postdoctoral researcher with Dawson Engler's Meta-Level Compilation Group at Stanford until summer 2004.

I received my PhD from the University of Utah in May 2002. My advisor was Prof. Wilson Hsieh. The topic of my dissertation is "Isolation, Resource Management, and Sharing in the KaffeOS Java Runtime System."

While a graduate student at Utah I was a member of the Flux Group, where I helped design and build the OSKit and Fluke Microkernel projects.

I worked on the Itsy project during a summer internship at the Compaq Western Research Laboratory in 1999.

I studied from 1989 to 1993 at the Humboldt University Berlin and the Technical University Berlin.

While in Berlin I worked for Mummert Consulting, a leading German consulting company in the banking and finance sector. I also interned at the Konrad-Zuse-Zentrum Berlin with the Scientific Visualization group in 1994.

I grew up in Sonneberg, Germany and went to high school at the Goetheschule in Ilmenau.

Godmar Back's Publications

1. "Rich Cloud-Based Web Applications with CloudBrowser 2.0." Xiaozhong Pan and Godmar Back. Proceedings of the 31st Annual ACM Symposium on Applied Computing. April 2016. pp. 758--765. (Best Paper Award).
   
   
2. "Tools and technologies: Visualizing research activity in the discovery layer in real-time." Data Visualization: A Guide to Visual Storytelling for Librarians. Godmar Back and Annette Bailey. Editted by Lauren Magnuson. Lanham, MD. Rowman & Littlefield. 2016.
   
   
3. "LUC: Limiting the Unintended Consequences of Power Scaling on Parallel Transaction-Oriented Workloads." Hung-Ching Change, Bo Li, Godmar Back, Ali R. Butt, and Kirk W. Cameron. Proceedings of the 29th IEEE Parallel and Distributed Processing Symposium. May 2015. pp. 324--333. [URL]
   
   
4. "Hacking Summon 2.0 The Elegant Way." Godmar Back and Annette Bailey. code4lib Journal. no. 26, . October 2014. [URL]
   
   
5. "VirtuOS: an operating system with kernel virtualization." Ruslan Nikolaev and Godmar Back. Proceedings of the Twenty-Fourth ACM Symposium on Operating Systems Principles. New York, NY, USA. 2013. pp. 116--132. [URL]
   
   
6. "Streamlining access to library resources." Robots in the Academic Library. Annette Bailey and Godmar Back. Editted by Edward Iglesias. Hershey, PA. IGI Global. 2013.
   
   
7. "The CloudBrowser Web Application Framework." Brian McDaniel and Godmar Back. Proceedings of the 3rd annual conference on Systems, Programming, and Applications: Software for Humanity. New York, NY, USA. 2012. pp. 141--156. [URL]
   
   
8. "A Library for Pattern-based Sparse Matrix Vector Multiply." Mehmet Belgin, Godmar Back, and Calvin J. Ribbens. International Journal of Parallel Programming. 39 (1). 2011. pp. 62--87.
   
   
9. "Perfctr-Xen: a Framework for Performance Counter Virtualization." Ruslan Nikolaev and Godmar Back. Proceedings of the 7th ACM SIGPLAN/SIGOPS International Conference on Virtual Execution Environments. New York, NY, USA. 2011. pp. 15--26. [URL]
   
   
10. "Operation Stacking for Ensemble Computations with Variable Convergence." Mehmet Belgin, Godmar Back, and Calvin J. Ribbens. International Journal of High Performance Computing Applications. 24 (2). 2010. pp. 194-212.
    
    
11. "Applicability of Pattern-based Sparse Matrix Representation for Real Applications." Mehmet Belgin, Godmar Back, and Calvin J. Ribbens. Proceedings of International Conference on Computational Science, ICCS 2010. 2010. pp. 203--211. [URL]
    
    
12. "An Infrastructure for Teaching CS1 in the Cloud." Michael Woods, Godmar Back, and Stephen Edwards. ASEE Southeast Section Annual Conference. 2010.
    
    
13. "Diagnosing memory leaks using graph mining on heap dumps." Evan K. Maxwell, Godmar Back, and Naren Ramakrishnan. Proceedings of the 16th ACM SIGKDD international conference on Knowledge discovery and data mining. New York, NY, USA. 2010. pp. 115--124. [URL]
    
    
14. "Web Services and Widgets for Library Information Systems." Godmar Back and Annette Bailey. Information Technologies and Libraries. 29 (2). June 2010. pp. 76--86. [URL]
    
    
15. "Fine-grained Isolation in Web Browsers Using Script Spaces." Amarjyoti Deka and Godmar Back. Poster at Usenix WebApps 2010 (WebApps'10). June 2010.
    
    
16. "Rating ILS Interoperability: A Proposal." Annette Bailey and Godmar Back. Information Standards Quarterly. 21 (4). 2009. pp. 17--19.
    
    
17. "Pattern-based sparse matrix representation for memory-efficient SMVM kernels." ICS '09: Proceedings of the 23rd international conference on Supercomputing. New York, NY, USA. 2009. pp. 100--109.
    
    
18. "The Pintos Instructional Operating System Kernel." Ben Pfaff, Anthony Romano, and Godmar Back. Proceedings of the 40th ACM Technical Symposium on Computer Science Education (SIGCSE 2009). Chattanooga, TN. March 2009. pp. 453--457.
    
    
19. "A Fast JPEG2000 Encoder That Preserves Coding Efficiency: The Split Arithmetic Encoder." Krishnaraj Varma, Hima B. Damecharla, Amy E. Bell, Joan E. Carletta, and Godmar Back. IEEE Transactions on Circuits and Systems I. 55 (11). December 2008. pp. 3711--3722.
    
    
20. "Pattern-based Code Generation for SMVM Kernels." Mehmet Belgin, Godmar Back, and Calvin J. Ribbens. Poster at Supercomputing 2008 (SC'08). November 2008.
    
    
21. "HDPV: interactive, faithful, in-vivo runtime state visualization for C/C++ and Java." Jaishankar Sundararaman and Godmar Back. Proceedings of the 4th ACM Symposium on Software Visualization (SoftVis'08). Ammersee, Germany. September 2008. pp. 47--56. [URL]
    
    
22. "Increasing the visibility of web-based information retrieval systems via client-side mash-ups." Godmar Back and Annette Bailey. Proceedings of the 8th ACM/IEEE-CS Joint Conference on Digital Libraries (JCDL'08). Pittsburgh, PA. June 2008. pp. 418. [URL] Demonstration.
    
    
23. "Program, Enhance Thyself! Demand-Driven Pattern-Oriented Program Enhancement." Eli Tilevich and Godmar Back. Proceedings of the Seventh International Conference on Aspect-Oriented Software Development (AOSD 2008). Brussels, Belgium. April 2008. pp. 13--24. [URL]
    
    
24. "ReplayCache: Exploiting Similarities for Predicting the Future." Ganesh C.N., Jaishankar Sundararaman, Ali R. Butt, and Godmar Back. Poster at 6th USENIX Conference on File and Storage Technologies (FAST 2008). February 2008.
    
    
25. "Application-Specific System Customization on Many-Core Platforms: The VT-ASOS Framework." Godmar Back and Dimitrios S. Nikolopoulos. STMCS: Second Workshop on Software Tools for Multi-Core Systems (STMCS). San Jose, CA. March 2007. [URL]
    
    
26. "Retrieving Known Items with LibX." Annette Bailey and Godmar Back. The Serials Librarian. 53 (4). 2007. pp. 125--140.
    
    
27. "Garbage collection-aware utility accrual scheduling." Shahrooz Feizabadi and Godmar Back. Real-Time Systems. 36 (1-2). 2007. pp. 3--22.
    
    
28. "An operation stacking framework for large ensemble computations." Mehmet Belgin, Calvin J. Ribbens, and Godmar Back. ICS '07: Proceedings of the 21st annual international conference on Supercomputing. Seattle, Washington. New York, NY, USA. 2007. pp. 83--92.
    
    
29. "From Uncertainty to Belief: Inferring the Specification Within." Ted Kremenek, Paul Twohey, Godmar Back, Dawson Engler, and Andrew Ng. accepted to Seventh Symposium on Operating Systems Design and Implementation (OSDI '06). USENIX Association. Seattle, WA. November 2006. pp. 161--176.
    
    
30. "The Distributed Open Network Emulator: Using Relativistic Time for Distributed Scalable Simulation." Craig Bergstrom, Srinidhi Varadarajan, and Godmar Back. Proceedings of the 20th Workshop on Principles of Advanced and Distributed Simulation. Singapore. May 2006. pp. 19--28. [URL]
    
    
31. "Automatic Memory Management in Utility Accrual Scheduling Environments." Shahrooz Feizabadi and Godmar Back. Proceedings of the 9th IEEE International Symposium on Object and component-oriented Real-time distributed Computing (ISORC 2006). IEEE. Gyeongju, South Korea. April 2006. pp. 11--19. [URL]
    
    
32. "LibX - A Firefox Extension for Enhanced Library Access." Annette Bailey and Godmar Back. Library Hi Tech. 24 (2). 2006. pp. 290--304.
    
    
33. "Java Garbage Collection Scheduling in Utility Accrual Scheduling Environments." Shahrooz Feizabadi and Godmar Back. 3rd Workshop on Java Technologies for Real-time and Embedded Systems (JTRES) colocated with OOPSLA 2005. ACM. October 2005. [URL] This workshop paper is superceded by the ISORC-2006 paper..
    
    
34. "The KaffeOS Java Runtime System." Godmar Back and Wilson C Hsieh. ACM Transactions on Programming Languages and Systems. 27 (4). 2005. pp. 583--630. [URL]
    
    
35. "Isolation, Resource Management and Sharing in the KaffeOS Java Runtime System." , Doctoral Dissertation, Godmar Back. University of Utah. 2002. [URL]
    
    
36. "DataScript - A Specification and Scripting Language for Binary Data." Godmar Back. Proceedings of the ACM Conference on Generative Programming and Component Engineering Proceedings (GPCE 2002), published as LNCS 2487. ACM. Pittsburgh, PA. October 2002. pp. 66-77. [URL]
    
    
37. "Reverse-Engineering Instruction Encodings." Wilson C. Hsieh, Dawson R. Engler, and Godmar Back. Proceedings of the USENIX 2001 Annual Technical Conference. USENIX Association. Boston, MA. June 2001. pp. 133--146. [URL]
    
    
38. "Quantifying the Energy Consumption of a Pocket Computer and a Java Virtual Machine." Keith Farkas, Jason Flinn, Godmar Back, Dirk Grunwald, and Jennifer Anderson. Proceedings of SIGMETRICS '00. Santa Clara, CA. June 2000. pp. 252--263. [URL]
    
    
39. "Processes in KaffeOS: Isolation, Resource Management, and Sharing in Java." Godmar Back, Wilson C. Hsieh, and Jay Lepreau. Proceedings of the Fourth Symposium on Operating Systems Design and Implementation (OSDI). USENIX Association. San Diego, CA. October 2000. pp. 333--346. [URL]
    
    
40. "Techniques for the Design of Java Operating Systems." Godmar Back, Patrick Tullmann, Leigh Stoller, Wilson C. Hsieh, and Jay Lepreau. Proceedings of the USENIX 2000 Annual Technical Conference. USENIX Association. San Diego, CA. June 2000. pp. 197--210. [URL]
    
    
41. "Drawing the Red Line in Java." Godmar Back and Wilson C. Hsieh. Proceedings of the Seventh Workshop on Hot Topics in Operating Systems (HOTOS). IEEE Computer Society. Rio Rico, Arizona. March 1999. pp. 116--121. [URL]
    
    
42. "The Flux OSKit: A Substrate for OS and Language Research." Bryan Ford, Godmar Back, Greg Benson, Jay Lepreau, Albert Lin, and Olin Shivers. Proceedings of the 16th ACM Symposium on Operating Systems Principles (SOSP). St. Malo, France. October 1997. pp. 38--51. [URL]
    
    
43. "Formal Methods: A Practical Tool for OS Implementors." Patrick Tullmann, Jeff Turner, John McCorquodale, Jay Lepreau, Ajay Chitturi, and Godmar Back. Proceedings of the Sixth Workshop on Hot Topics in Operating Systems (HOTOS). IEEE Computer Society. Cape Cod, MA. May 1997. pp. 20--25. [URL]
    
    
44. "Microkernels Meet Recursive Virtual Machines." Bryan Ford, Mike Hibler, Jay Lepreau, Patrick Tullmann, Godmar Back, and Stephen Clawson. Proceedings of the Second Symposium on Operating Systems Design and Implementation (OSDI). USENIX Association. Seattle, WA. October 1996. pp. 137--151. [URL]
    
    

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