Image courtesy of MIT

On March 10, Massachusetts Institute of Technology professor Barbara Liskov won this year's $250,000 Turing Award. Often described as the “Nobel Prize in computing,” the award was given for helping to make computer programs more reliable, secure and easy to use. Liskov is only the second woman to receive the honor.

“Her exceptional achievements have leapt from the halls of academia to transform daily life around the world,” MIT Provost L. Rafael Reif said. “Every time you exchange e-mail with a friend, check your bank statement online or run a Google search, you are riding the momentum of her research.”

The Association for Computing Machinery, which awards the Turing, noted that  Liskov was the first U.S. woman to be awarded a Ph.D. in computer science, which she received from Stanford University in 1968. Liskov heads the Programming Methodology Group in the Computer Science and Artificial Intelligence Laboratory at MIT, where she has conducted research since 1972. She is currently working in grid computing, on projects such as the Infrastructure for Resilient Internet Systems, or IRIS — research aimed at developing a novel decentralized infrastructure, based on distributed hash tables (DHTs), that will enable a new generation of large-scale distributed applications. (DHTs are robust in the face of failures, attacks and unexpectedly high loads. The IRIS website says: “DHTs are scalable, achieving large system sizes without incurring undue overhead. They are self-configuring, automatically incorporating new nodes without manual intervention or oversight. They provide a simple and flexible interface and are simultaneously usable by many applications.”)

Liskov's early innovations in software design have been the basis of every important programming language since 1975, including Ada, C++, Java and C#. Liskov's most significant impact stems from her influential contributions to the use of data abstraction, a valuable method for organizing complex programs. She was a leader in demonstrating how data abstraction could be used to make software easier to construct, modify and maintain. Many of these ideas were derived from her experience at Mitre Corp in building the VENUS operating system, a small, interactive timesharing system.

Advances in software design

In another contribution, Liskov designed CLU, an object-oriented programming language incorporating clusters to provide coherent, systematic handling of abstract data types. She and her colleagues at MIT subsequently developed efficient CLU compiler implementations on several different machines, an important step in demonstrating the practicality of her ideas. Data abstraction is now a generally accepted fundamental method of software engineering that focuses on data rather than processes.

Building on CLU concepts, Liskov followed with Argus, a distributed programming language. Its novel features led to further developments in distributed system design that could scale to systems connected by a network. This achievement laid the groundwork for modern search engines, which are used by thousands of programmers and hundreds of millions of users every day and which face the challenges of concurrent operation, failure and continually growing scale.

Her most recent research focuses on techniques that enable a system to continue operating properly in the event of the failure of some of its components. Her work on practical Byzantine fault tolerance demonstrated that there were more efficient ways of dealing with arbitrary (Byzantine) failures than had been previously known. Her insights have helped build robust, fault-tolerant distributed systems that are resistant to errors and hacking. This research is likely to change the way distributed system designers think about providing reliable service on today's modern, vulnerable Internet.

The Turing Award is given annually by the Association for Computing Machinery and is named for British mathematician Alan M. Turing, who helped the Allies crack the Nazi Enigma code during World War Two. Liskov will formally receive the award at an ACM gathering on June 27 in San Diego.

 —Dan Drollette, iSGTW. Portions excerpted from MIT Tech Talk