Barbara Liskov Wins Turing Award
ACM cites 'foundational innovations' in programming language design
By
Dr. Dobb's Journal
Mar 10, 2009
URL:http://www.ddj.com/hpc-high-performance-computing/215801518
Barbara Liskov has won
the Association for Computing Machinery's A.M. Turing Award, one of the
highest honors in science and engineering, for her pioneering work in
the design of computer programming languages. Liskov's achievements
underpin virtually every modern computing-related convenience in
people's daily lives.
Liskov, the first U.S. woman to earn a PhD in computer science,
was recognized for helping make software more reliable, consistent and
resistant to errors and hacking. She is only the second woman to
receive the honor, which carries a $250,000 purse and is often
described as the "Nobel Prize in computing."
Liskov heads the Programming Methodology Group in the Computer
Science and Artificial Intelligence Laboratory at MIT, where she has
conducted research since 1972. Last year, she was named an Institute
Professor, the highest honor awarded to an MIT faculty member.
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
MIT in building the VENUS operating system, a small timesharing system
that dramatically lowers the cost of providing computing and makes it
more interactive.
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.
On the occasion of her winning the Turing Award, MIT Institute
Professor Barbara Liskov discussed her role in shaping in the past,
present and future of computer science.
Q: When you began your career in computer science, it was still
a relatively young field. How have you seen this discipline evolve over
time -- at MIT and elsewhere?
A: The change has been tremendous. When I started, most of the
field was unexplored and there were obvious problems everywhere -- lots
of low-hanging fruit, but also very fundamental issues that were poorly
understood and very confusing. Today the field is on a very sound
foundation. There are still many problems to work on, but now this work
happens in the context of all that has gone before. When I started,
this context was missing, so you just struck out on your own.
Q: Looking back at your career, what is the single accomplishment of which you are most proud?
A: Probably the development of the concept of data abstraction
and the CLU programming language. This work was done at MIT in the
1970s.
Q: Where do you plan to focus your research going forward?
A: Today I am working primarily on distributed systems --
systems that run on many computers connected by a network like the
Internet. My focus recently has been on the security of online storage.
I believe that more and more users will store their information online,
but the storage they use needs to be implemented so that they don't
lose their information, their information is available when they need
it, and they can be confident that their confidential information will
not be leaked.
Q: As the first woman to earn a PhD in computer science, what
advice would you give to other women who are considering going into
this field?
A: I have found computer science to be a wonderful field to work
in. I think the main reason is that the kind of thinking and
problem-solving it requires matches my abilities. I believe that
finding work to do that you like and are good at is the most important
way to find a satisfying career. Young women (and young men) who find
that computer science is a match for them should pursue it. There is
lots of interesting work remaining to be done.
Q: When you began studying computer science at Stanford,
computers were big mainframes and the Internet was still in the distant
future. Today, computers fit in the palm of our hands -- many are much
smaller -- and the Internet is ubiquitous. Given that you have watched
these transformations over the last five decades from a front-row seat,
what do you think the next half-century will hold?
A: I don't have a crystal ball! It seems obvious that computers
and the Internet will continue to be very important to individuals,
companies and society. But I don't know the exact form this will take.
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