MIT Reports to the President 1995-96


The MIT Laboratory for Computer Science (LCS) is an interdepartmental laboratory whose principal goal is research in information science and technology toward a better life for all people.

Founded as Project MAC in 1963, the Laboratory developed one of the world's earliest time-shared computer systems. This early research on the Compatible Time Sharing System (CTSS) and its successor, MULTICS, made possible in the 60s and early 70s innovative developments such as the writing of operating systems in high-level programming languages, virtual memory, tree directories, on-line scheduling algorithms, line and page editors, secure operating systems, concepts and techniques for access control, computer-aided design, and two of the earliest computer games, space wars and computer chess.

These early developments laid the foundation for the Laboratory's work in the 1970s on knowledge based systems -- for example, the MACSYMA program for symbolic mathematics -- natural language understanding, and (with BBN) the development and use of packet networks via the ARPANET. During this same period, the Laboratory developed theoretical results in complexity theory and linked cryptography to computer science through concepts and algorithms for public encryption. In the late 1970s, Project MAC, renamed as the Laboratory for Computer Science, embarked on research in clinical decision making, public cryptography, distributed systems and languages and parallel systems. These led to the RSA encryption algorithm, data abstractions, the CLU and ARGUS distributed systems, the dataflow principle and associated languages and architectures of parallel systems, local area ring networks, program specification and workstation development, where the Laboratory contributed the earliest UNIX ports and compilers, and the Nubus architecture, now used in commercial computers, such as Apple's Macintosh. This research also led to the X Window System, a computer intercommunication and user interface system, developed together with Project Athena and widely used by industry.

The Laboratory's current research falls into four principal categories: Information Infrastructure and Distributed Systems; Human Interaction/Intelligent Systems; Computationally Intense Systems; and Theory. The principal goals of these four categories are as follows:

In the areas of Information Infrastructure and Distributed Systems, we wish to understand principles and pursue technologies for the architecture and use of highly scaleable information infrastructures from the organizational to the international level. Transactions among such distributed systems are likely to involve beyond conventional electronic mail and file transfer, the purchase and sale of information and information services (electronic commerce), electronic shopping, health care, education, groupwork across space and time, automation of computer-to-computer actions and many more.. This research is expected to have a broad impact on future systems because virtually every machine will be connected to some information infrastructure and such infrastructures are expected to last for a very long time..

In the Human Interaction/Intelligent Systems area, our technical goals are to understand and construct programs and machines that have greater and more useful sensory and cognitive capabilities so that they may communicate with one another and with people toward useful ends. Examples include the use of advanced graphics and interactive spoken dialogue between people and machines. This area also includes programs that reason about clinical issues and help in clinical decision making and health care.

In the Computationally Intense Systems area, we strive to harness the power and economy of numerous processors working on the same task. Research in the area involves the analysis and construction of various parallel hardware architectures, programming languages and operating systems that yield, over a broad set of applications, cost-performance improvements of several orders of magnitude relative to single processors. We are also carrying out research on the uses of computationally intense systems in several application areas for the purpose of improving architectures and programs that we develop, based on their utility.

Taken together, these three thrusts in infrastructure, human interaction/intelligent systems and computationally intense systems define the Laboratory's overarching goal: development, understanding and better human communication with tomorrow's information systems.

In the Laboratory's fourth category of research, Theory, we strive to discover and understand the fundamental forces, rules, and limits of Information Science and Technology. As a result, theoretical work permeates our research efforts in the other three areas; for example, in the pursuit of parallel algorithms, fault tolerant computer networks, and privacy and authentication of communications. Theory also touches on the logic of programs, the inherent complexity of computations, and the use of cryptography and randomness in the formal characterization of knowledge. The Laboratory expends a great deal of effort in theoretical computer science because its impact upon our world is expected to continue its past record of improving our understanding and helping us pursue new frontiers with new models, concepts, methods, and algorithms.

Research highlights during the reporting period are as follows:

The World Wide Web (W3): The Laboratory has founded a W3 Consortium similar to the X Consortium. As of this report, 146 organizations have joined this consortium in order to participate in and contribute to the orderly evolution of the World Wide Web (W3). That process, and the consortium, are directed by Mr. Tim Berners-Lee, the inventor of W3. A team of researchers and developers has been assembled at LCS and at our European affiliate INRIA (France), to staff the consortium effort. The team currently is very close to its planned size of some 15 full-time equivalents at each site, plus students. We are currently exploring a relationship in Japan similar to that with INRIA so that we may have Asian contributions to the evolution of W3. We are proud to be involved in the continued development of W3, which is widely used by millions of people and which enhances and is enhanced by the pursuit of our objectives in understanding and building scaleable international information infrastructures.

Curl : A New Distributed Environment : Professor Stephen Ward and his research group (Computer Architecture Group) have embarked on a very ambitious effort--the development of a new language system, called Curl, which is aimed to become for future distributed systems what languages and operating systems are to today's individual computer systems. Curl is a gentle slope system (GSS) meaning that incremental human effort results in incrementally greater functionality, without major discontinuities. Curl should make possible for non-programmers and programmers alike the tailoring of distributed systems to their needs.

Multiprocessor Architectures: Professor Arvind's group is currently engaged in building the StarT family of parallel computers. The group has recently entered into a joint research agreement with IBM based on StarT-Voyager technology. In addition, the group is involved in the construction and evaluation of StarT-jr. -- a tightly-coupled network of workstations built using existing technologies. The computation nodes are Pentium/Pentium Pro workstations donated by Intel running Linux. An important role of StarT-jr is to serve as a development platform for StarT-Voyager software. The group is also active in all aspects of parallel software research through exploration of implicitly parallel programming languages (like pH and Id) and the development of applications in these languages through collaborations with physical scientists.

Spoken Language Systems: Our Spoken Language Systems Group has expanded and strengthened its capabilities through continued development of its constituent component technologies. The speech recognizer was modified to incorporate a novel probabilistic framework which learns from both positive and negative examples. Research in multilingual language processing continues, with new emphasis on Mandarin. Research in dialogue modeling was conducted in the area of "displayless" human-computer interactions. Remote access to the worldwide web has been introduced using telephone-based speech recognition, and a new knowledge domain of detailed restaurant information has been developed.

Advanced Graphics: A new effort has begun at LCS under the leadership of Professor Seth Teller. It involves the automatic digitization of large physical environments, such as the City of Cambridge, through use of vehicular cameras that travel the streets of the city. The Synthetic Imagery Group is also investigating strategies for rendering visually the contents of immense datasets, and interactive teaching techniques for undergraduates. We are currently in the process of expanding this important area of research with additional faculty. We aspire to complement our spoken language systems with advanced visual approaches toward a more integrated and more natural human machine interaction.

Novel Operating System Approaches : Research by Professor Frans Kaashoek and his research group (Parallel and Distributed Operating Systems Group) has led to a new approach for constructing tomorrow's operating systems. Called Exokernels, this approach entails a very efficient and "thin" operating system aimed at high performance and a library of desirable functions which are available to applications, as needed. Performance improvements of more than an order of magnitude have been measured using this approach.

During this reporting period, the Laboratory's Distinguished Lecturer Series included presentations by Professor John Ousterhout, Distinguished Engineer, University of California at Berkeley, Dr. Andrew J. Viterbi, Chief Technical Officer, Qualcomm, Incorporated, Dr. James Clark, Chairman and CEO, Netscape, Dr. Arati Prabhakar, Director of the Nation Institute of Standards and Technology, Dr. Robert Metcalfe, Executive Correspondent, Infoworld and Mr. Bill Gates, Chairman and CEO, Microsoft.

The Laboratory is organized into 18 research groups, an administrative unit, and a computer service support unit. The Laboratory's membership comprises a total of 443 people, including 84 faculty and research staff, 142 graduate students, 116 undergraduate students, 65 visitors, affiliates, and postdoctoral associates and fellows, and 36 support staff. The academic affiliation of most of the Laboratory's faculty and students is with the Department of Electrical Engineering and Computer Science (EECS).

About 70 percent of the Laboratory's funding comes from the US Government's Defense Advanced Research Projects Agency (DARPA). The Laboratory is also funded by and has extensive links with industrial organizations. These include partnerships for the construction of major hardware systems, consortia for the development and maintenance of standards, such as the World Wide Web, and joint studies on research areas of common concern.

Michael L. Dertouzos

MIT Reports to the President 1995-96