Virtual Machines: Versatile Platforms for Systems and Processes

Virtual Machine technology applies the concept of virtualization to an entire machine, circumventing real machine compatibility constraints and hardware resource constraints to enable a higher degree of software portability and flexibility. Virtual machines are rapidly becoming an essential element in computer system design. They provide system security, flexibility, cross-platform compatibility, reliability, and resource efficiency. Designed to solve problems in combining and using major computer system components, virtual machine technologies play a key role in many disciplines, including operating systems, programming languages, and computer architecture. For example, at the process level, virtualizing technologies support dynamic program translation and platform-independent network computing. At the system level, they support multiple operating system environments on the same hardware platform and in servers.

Historically, individual virtual machine techniques have been developed within the specific disciplines that employ them (in some cases they aren't even referred to as "virtual machines”), making it difficult to see their common underlying relationships in a cohesive way. In this text, Smith and Nair take a new approach by examining virtual machines as a unified discipline. Pulling together cross-cutting technologies allows virtual machine implementations to be studied and engineered in a well-structured manner. Topics include instruction set emulation, dynamic program translation and optimization, high level virtual machines (including Java and CLI), and system virtual machines for both single-user systems and servers.

• Examines virtual machine technologies across the disciplines that use them-operating systems, programming languages and computer architecture-defining a new and unified discipline.
• Reviewed by principle researchers at Microsoft, HP, and by other industry research groups.
• Written by two authors who combine several decades of expertise in computer system research and development, both in academia and industry.

About the Authors

James E. Smith is a Professor in the Department of Electrical and Computer Engineering at the University of Wisconsin-Madison. He first joined the University of Wisconsin in 1976, after receiving his PhD in Computer Science from the University of Illinois. From 1979 to 1981, he took a leave of absence to work for the Control Data Corporation in Arden Hills, MN, participating in the design of the CYBER 180/990. From 1984 to 1989, he participated in the development of the ACA ZS-1, a scientific computer employing a dynamically scheduled, superscalar processor architecture. In 1989, he joined Cray Research, Inc. in Chippewa Falls, WI. While at Cray Research, he headed a small research team that participated in the development and analysis of future supercomputer architectures.

In 1994, he re-joined the ECE Department at the University of Wisconsin. His recent research concerns the development of the virtual machine abstraction as a technique for providing high performance through co-design and tight coupling of virtual machine hardware and software. Prof. Smith was the recipient of the 1999 ACM/IEEE Eckert-Mauchly Award for his contributions to the field of computer architecture.

Ravi Nair has been a Research Staff Member since 1978 at the IBM Thomas J. Watson Research Center, where he has helped in the architecture and design of a number of processors. He has worked in the areas of computer architecture, performance analysis, multiprocessor virtualization, design automation, and testing, and has several publications, patents, and IBM awards in these areas. Among the many design and analysis tools he has developed are binary rewriting tools for profiling, trace generation, and simulation. His current interests include processor microarchitecture, dynamic compilation, and virtual machine technology. Dr. Nair graduated with a B.Tech. degree in electronics and electrical communication from IIT, Kharagpur in 1974, and with a Ph.D. degree in Computer Science from the University of Illinois in 1978. He spent a sabbatical year at Princeton University and has also taught at Columbia University. Dr. Nair is a member of the IBM Academy of Technology and a Fellow of the IEEE.