Thursday, March 29, 2007

Mark McCahill at Duke

I am quite pleased to announce that Mark McCahill is leaving the University of Minnesota for a position here at Duke University as our architect of e-learning and collaborative systems!

Mark has been developing and popularizing a number of Internet technologies since the late 1980s. He will bring to Duke the benefits of his deep background and rich experiences in collaborative systems development, large scale information system development and deployment, and 3D visualization.

After receiving a bachelor's degree in chemistry at the University of Minnesota, Mark took a job doing analytical chemistry and analyzing the results on the campus mainframe. In 1989, Mark led a team at the University of Minnesota that developed one of the the first popular Internet e-mail clients (POPmail) for the Macintosh (and later the PC).

In 1991, Mark led the original Internet Gopher development team and helped invent a simple way to navigate distributed information resources on the Internet. Internet Gopher's menu-based hypermedia paved the way for the popularization of the Web and was the de-facto standard for Internet information systems in the early-to-mid 1990s. In 1994-95 Mark's team developed GopherVR, a 3D user interface to Internet Gopherspace.

Working with other pioneers such as Tim Berners-Lee, Marc Andreessen, Alan Emtage and Peter J. Deutsch (creators of Archie) and Jon Postel, Mark was also involved in creating and codifing the standard for Uniform Resource Locators (URLs). Most recently Mark has served as one of the six principal architects of the Croquet project and was instrumental in founding the Croquet Consortium.

I look forward to working closely with Mark as we apply the lessons learned from first generation Internet information systems to next generation collaborative systems including enterprise-integrated applications based on Croquet.

Wednesday, March 21, 2007

Changing Times

In a recent Point of View article in The Chronicle Review, Cathy N. Davidson expresses her opinion on the Middlebury College History Department's recent snubbing of Wikipedia and why academic institutions can no longer ignore the changes that are being brought about by social software technologies and the types of creative dynamics they enable. The issues discussed in Cathy's piece have relevance to social collaborative tools such as wikis and the types of co-constructed knowledge spaces that Croquet-based educational environments make possible.

Today's co-constructed 3D environments provide us with the potential to disseminate ideas as visual and dynamic objects in the way that text-based facts and ideas are constructed and disseminated via today's Wikipedia. This capability will have a profound effect on the academic world in that it has the potential to fundamentally change to how we communicate and learn. The changing legitimacy of Wikipedia is only the tip of the iceberg. The advent of social software and self-regulating large-scale group dynamics stands to challenge traditional models of instruction, authorship, copyright, and the value of static auteur-generated scholarly works.

Monday, March 12, 2007

Metaverse Scalability

Back in the mid-1990s, while we were designing ViOS as a large-scale commercial server-dependent and massively-multiuser metaverse application, I was deeply concerned that its success as a widely-used platform would be its undoing. Thats because, unlike the web, multi-user immersive environments require relatively constant interactions between clients and servers - and those interactions don't scale well for large numbers of users.

Virtual environments such as multi-user flight simulators and first-person shooters rely on many independent server sessions that are limited to a relatively few users at any one time. Massively multi-user metaverses, on the other hand, require the client to be updated as fast as things happen within the environment. This means that large-scale metaverses need a lot of horsepower in the server layer since every move and every action of every avatar must be conveyed to every client. This puts a tremendous load on a few servers for even the most trivial of interactions. The approach simply doesn't scale to support the widespread global information systems that the Croquet architecture is being designed to make possible.

Our strategy back at ViOS, Inc. was to simply re-tune the system and put up more servers as the loads increased - hoping for the best. That approach would work well for Intranet applications that serviced relatively small numbers of clients. It even worked well for ViOS' initial user base of around 15,000 unique users. Problem was that once we had several thousand simultaneous Viosians tooling about in the landscape, they began to overload our interactivity servers, resulting in performance problems and service interruptions. Since there wasn't a lot of cash flow or investment capital during the 2001 post dot-com financial downdraft, we were unable to add servers at a rate that could meet the demand. If we had, it might have led to another few years of success for the ViOS metaverse platform - but sooner or later we would have been brought down by fundamental flaws in our approach as a bottlenecked client-server based architecture.

The Croquet technology has been developed with these lessons in mind. It is designed to scale in support of interconnected multiverses of millions of users without the need for any dedicated server infrastructure. Croquet's architecture makes it possible to develop metaverse applications in which, anyone can freely put up content in islands of any size, interlink those islands with any number of other islands, and control access to those islands.

By contrast Second Life makes money by controlling who can create islands and how those islands are linked to each other. It also has a very similar technical architecture to that of ViOS - a vintage twentieth century client-server architecture with with single points of failure, inertia, and control. It's been interesting to watch Linden Lab's struggle with the inevitable technical problems faced by Second Life as a result of its recent popularity, constrained architecture, and non-scaling technical approach. For details on some of those struggles click here, here, and here.

Sunday, March 04, 2007

Metaverse Interoperability

For some time now, Laurence Rozier has been developing a message format that, among other things, can allow for interoperability between metaverse environments. Called Remote Actions Packets (RAP), it basically makes it possible for someone to do something in, say, Second Life and have that same action replicated in Croquet - and vice versa. RAP messages consist of an actor identifier, an action name, and an encoded list of stage directions.

In this simple video, you will see a Croquet window (on the right) side by side with a Second Life window (on the left). Each shows a live running world containing a simple cube. When the cube in Second Life is clicked, a script runs that causes the cube to move. Almost immediately, you will see this action replicated in the Croquet world. Next, a Croquet menu select initiates a move of the cube in the Croquet window. After a short delay, the simple cube movement is mirrored in Second Life.

The implications of Laurence's work are that Croquet worlds can now be made to mirror aspects of Second Life worlds - and vice versa. This also means that there's now a way by which actions taken within metaverses such as Croquet can be logged to text files. That particular capability would be of great importance to educators, researchers, and marketers who are interested in understanding what kinds of things have taken place in Croquet environments.

Thursday, March 01, 2007


Sophie is new open source Squeak Smalltalk-based software application for creating digital multimedia books that are easy to build. A product of the Institute for the Future of the Book, It is in essence a multimedia authoring system. Sophie-generated books can resemble regular books containing text and pictures, or they may also contain video, audio clips, images in a slide show, other books, links out to the web, and allow for reader interaction.

Sound a lot like what the web was supposed to be? You bet. The difference is that Sophie has been developed as a tool to enable non-technical people to assemble digital documents without needing to learn complex computer languages or to rely on programmers. Still, Sophie uses a human-readable distributed XML format to ensure that a user's content remain accessible for decades to come. Should a particular title need features beyond those provided by Sophie (such as performance or databasing) there is little in the way of preventing those systems from being plugged in on a per book or per distribution basis.

The intent of Sophie is to facilitate the shift from page to screen as a means of scholarly communication. Many academics find it difficult to move to the digital medium because of the technical barriers to doing so in a sophisticated manner. That has a lot to do with why the Research in Information Technology Program of the the Andrew W. Mellon Foundation and the University of Southern California School of Cinematic Arts chose to fund this project.

Sophie is device and OS independent - and best of all, because of its implementation in Squeak, it is fundamentally compatible as a powerful tool within Croquet-based immersive environments. In fact, we are currently exploring what it might take to combine these powerful technologies into a single application and in so doing, bring to bear the power of distributed multimedia authoring directly into late-binding and device-independent collaborative immersive environments - kind of like a powerful open source groupware solution with 3D capabilities. To bring these technologies together would be of great value to education and beyond - and would represent an excellent choice for our developing communities. :)

Sophie is available here, and a video demo is here (the demo starts at: 23:32).