Alan C. Kay

Back to the future: the story of Squeak, a practical Smalltalk written in itself

Squeak is an open, highly-portable Smalltalk implementation whose virtual machine is written entirely in Smalltalk, making it easy to. debug, analyze, and change. To achieve practical performance, a translator produces an equivalent C program whose performance is comparable to commercial Smalltalks.Other noteworthy aspects of Squeak include: a compact object format that typically requires only a single word of overhead per object; a simple yet efficient incremental garbage collector for 32-bit direct pointers; efficient bulk-mutation of objects; extensions of BitBlt to handle color of any depth and anti-aliased image rotation and scaling; and real-time sound and music synthesis written entirely in Smalltalk.

The early history of Smalltalk

Most ideas come from previous ideas. The sixties, particularly in the ARPA community, gave rise to a host of notions about “human-computer symbiosis” through interactive time-shared computers, graphics screens and pointing devices. Advanced computer languages were invented to simulate complex systems such as oil refineries and semi-intelligent behavior. The soon to follow paradigm shift of modern personal computing, overlapping window interfaces, and object-oriented design came from seeing the work of the sixties as something more than a “better old thing”. That is, more than a better way: to do mainframe computing; for end-users to invoke functionality; to make data structures more abstract. Instead the promise of exponential growth in computing/

A Personal Computer for Children of All Ages

/volume demanded that the sixties be regarded as “almost a new thing” and to find out what the actual “new things” might be. For example, one would compute with a handheld “Dynabook” in a way that would not be possible on a shared mainframe; millions of potential users meant that the user interface would have to become a learning environment along the lines of Montessori and Bruner; and needs for large scope, reduction in complexity, and end-user literacy would require that data and control structures be done away with in favor of a more biological scheme of protected universal cells interacting only through messages that could mimic any desired behavior. Early Smalltalk was the first complete realization of these new points of view as parented by its many predecessors in hardware, language and user interface design. It became the exemplar of the new computing, in part, because we were actually trying for a qualitative shift in belief structures—a new Kuhnian paradigm in the same spirit as the invention of the printing press—and thus took highly extreme positions which almost forced these new styles to be invented.

Croquet - a collaboration system architecture

This note speculates about the emergence of personal, portable information manipulators and their effects when used by both children and adults. Although it should be read as science fiction, current trends in miniaturization and price reduction almost guarantee that many of the notions discussed will actually happen in the near future.

Interview with Alan Kay

Croquet is a computer software architecture built from the ground up with a focus on deep collaboration between teams of users. It is a totally open, totally free, highly portable extension to the Squeak (Ingalls et al., 2002) programming system. Croquet is a complete development and delivery platform for doing real collaborative work. There is no distinction between the user environment and the development environment. Croquet is focused on interactions inside of a 3D shared space that is used for context based collaboration, where each user can see all of the others and what their current focus is. This allows for an extremely compelling shared experience. A new collaboration architecture/protocol called TeaTime has been developed to enable this functionality. The rendering architecture is built on top of OpenGL (Woo et al., 1999).

Recommendations for interdisciplinary study of tipping points in natural and social systems

The legendary Alan Kay and Roy E. Disney have graciously appeared on camera for interviews and joined the ACM Computers in Entertainment magazines editorial board. Alan and Roy are two of the nicest people to talk to and work with. Alan talked about soft fun versus hard fun, and his research on Squeak for enhancing and amplifying learning in childrens education. Roy told us about educators versus entertainers, and his views on traditional and CGI animations. The video clips of the interviews are available at http://www.acm.org/pubs/cie/oct2003/index.htmlAlan Kay, HP Fellow and President of Viewpoints Research Institute, is best known for the idea of personal computing the conception of the intimate laptop computer, and the inventions of the now ubiquitous overlapping-window interface and modern object-oriented programming. His deep interests in children and education were the catalyst for these ideas, and they continue to be a major source of inspiration. In the past, Alan has been a Xerox Fellow, Chief Scientist of Atari, Apple Fellow, and Disney Fellow. More information is available at http://www.squeakland.org/community/biography/alanbio.html and http://www.viewpointsresearch.org/alan.html

Scalability of Collaborative Environments

In September 2009, the U.S. National Science Foundations (NSF) Advisory Committee for Environmental Research and Education (AC-ERE) released “Transitions and Tipping Points in Complex Environmental Systems,” a report that advocates sweeping change in the way environmental research and education are sponsored and conducted. The conviction of the committee that physical and life scientists, engineers, educators, and social scientists must work collaboratively to understand the dynamics of complex environmental systems should resonate with AGUs membership. A major theme of the AC-ERE report is that scientists need to understand environmental systems that, partly owing to human activity, may be approaching thresholds for irreversible change. This theme echoes sentiments expressed in the geosciences community, such as by Rockstrom et al. [2009], who estimate the magnitudes of thresholds for irreversible changes in nine key Earth subsystems and focus on how human activities have driven systems closer—or even past—some thresholds. The AC-ERE report argues that understanding natural systems will require integrated research among geoscientists, social scientists, ecologists, and others.

The Dynabook - Past, Present, and Future

Collaborative environments range from the very primitive (IM) to a rich mixture of media, computation, and three-dimensional graphics. Critical to all such systems is scalability: how many users can a system support in a single session? How many simultaneous sessions can be supported? These questions ultimately reduce to bandwidth and computation consumption of the collaborative system; the values, in turn, depend upon the architectural choices made in the implementation. Should the system be client-server or peer-to-peer? Should data or computation be replicated? Are there tradeoffs? Does it depend on the nature of the collaboration? In this paper, we derive bounds on bandwidth and latency for consistent collaborative systems. A consistent system is one in which all participants agree on the order of events across all peers. We examine and calculate the bandwidth and latency bounds on various system architectures. We calculate a theoretical lower bound for computational and bandwidth complexity, and compare the architectural bounds to the lowest global bound

Graphical user interfaces

Paper not received in time for inclusion in the Conference Proceedings. A full paper will be distributed at the Conference.

The cuneiform tablets of 2015

Alan Kay presented the history of man-machine interfaces, in particular graphical user interfaces. His lecture gained its vividness mainly from demonstrations and several historical videos. This is hardly reproducible in a paper. Therefore, we refer the reader to the DVD recording of Alan Kay’s talk (DVD No. 2).