Program: Sunday, Monday

Software, Abstraction, and Visualisation, James Noble

Abstract. Abstraction is rather out of fashion in contemporary computer science. Why waste time and effort struggling to design interfaces, APIs, or domain models when vibe-coding firms are valued in the billions, when UML is more despised than COBOL, and when people have "had enough of experts" (carbon based experts, anyway)? Why try to visualise the design and operation of our computer systems, let alone formalise or attempt to understand them, when we can talk to our programs as easily as Adam & Eve could talk to the snake in the garden of Eden?

In this keynote, I'll argue that while current commodity laptops are tens of thousands of times more powerful than the ZX81 that I started on, they're not ten thousand times better at supporting programming, at helping people to learn how to program, and especially not at helping people understand what their programs do. I'll argue that the way people relate to computers is based on human psychology, rather than machine performance. Finally, I'll speculate that instead of bringing an end to programming, we are just as likely to be on the verge of a new beginning.

Bio. James Noble is an independent creative researcher & programmer based in Wellington, New Zealand. After completing honours and doctoral degrees at Victoria University of Wellington (VUW), James worked at the University of Technology, Sydney, the Microsoft Research Institute at Macquarie University, and is recovering from a long stint as professor of computer science & software engineering at VUW. James’s research centres around software design. This includes the design of the users’ interface, the parts of software that users have to deal with every day, and the programmers’ interface, the internal structures and organisations of software that programmers see only when they are designing, building, or modifying software. His research in both of these areas is coloured by a longstanding interest in object-oriented approaches to design, and topics he has studied range from aliasing and object ownership, programming languages, design patterns, agile methodology, via usability, visualisation and computer music, to postmodernism and the semiotics of programming.

Visualizing Program State in the Pernosco Debugger, Robert O’Callahan (Joint Keynote with SCAM)

Abstract. "Omniscient" debuggers have efficient and complete access to all program states that occurred during some run(s) of the program. The question then is, what is the best way to visualize this data to enable users to debug their programs in the most effective, time-efficient and fun manner?
The "Pernosco" debugger is one attempt to answer this question.
I will describe the principles we used when designing the Pernosco interface, some of the novel visualizations of dynamic state supported by Pernosco, and what we learned as we built it and deployed it to customers. In particular I will focus on the value of visualizing state across time as opposed to traditional debuggers that mostly only render the state at a given point in time. I will try to distinguish visualizations that are useful from those that are merely visually appealing. A critical aspect of debugging is mapping machine state back to "source level" state, typically via "debuginfo" emitted by the compiler. I'll talk about how Pernosco visualizes the relationship of state to source code, and how that could be extended in the future if we had a deeper understanding of the source code.

Bio. Robert O'Callahan did academic research (PhD Carnegie Mellon, IBM Research) for several years and then joined Mozilla to work on the Firefox browser engine for many more years, becoming a Distinguished Engineer at Mozilla. While at Mozilla he led the rr project to develop a practical, open-source record-and-replay debugger; rr has many users and he continues to maintain it today. In 2016 he left Mozilla to found Pernosco, a commercial omniscient debugger built on rr. In 2022 he joined Google Research to work on various projects mostly unrelated to debugging. He lives in New Zealand and enjoys hiking, board games and lay preaching.