• Hernan Epelman-Wang (hernan): Graphics System, Events System, Applications Framework. Also worked on CASE tools, Object Store and various documentation efforts.

• Sidney Markowitz (sidney): Object System, Condition System, Object Store, Build Process.

• Brian Roddy (brian, Brian Roddy, bjr, rod): User Interface, SK8Script, Collections, CASE tools, SK8 to Java output and the Java SK8 runtime. Also Group Manager.

• Adam Chipkin (adam, chip): worked on early SK8 graphics and then implemented the first real version of SK8Script. Left Apple in 1994.
• Ruben Kleiman (ruben, kleiman): Initial Creator of SK8. Directed the SK8 effort until he left Apple in 1994.
• David Vronay (ice): worked on the early versions of SK8 graphics and user interface. Left the SK8 effort in 1992.
• David Yost (yost): interface to QuickTime, Error checking, and safe use of system calls. Now in the User Experience Research Group in ARL.

And we would be remiss if we didn't thank the management who helped our project, most importantly the tireless efforts of Jim Spohrer, as well as the great work of Mark Miller and Rick LeFaivre.

There are many others who have helped us on SK8. The SK8 About Box is a small attempt at a list. Thanks to them all. We couldn't have done it without them.

How SK8 Grew
The SK8 project was created by Ruben Kleiman when he joined Apple in 1987. He came to Apple to develop a highly flexible, object-oriented user interface and multimedia development environment which could be used to create not only applications, but also high-level development environments suitable for any specific domains (e.g., training, games, planning and scheduling, accounting and finance, music theory and performance, games).

Apple was the ideal place to start this work. HyperCard, with its direct manipulation interface and scripting language, had already yielded drammatic increases in productivity for authors of multimedia titles. While HyperCard was great for simple applications built by end users, it was too restrictive for profesional programmers to use and its programming paradigm (i.e., stacks of cards) was fixed. One of the guiding questions for SK8 was how to extend these benefits to the wider programming community.

The first part of the work was devoted to developing a powerful, yet simple object system. The result was MacFrames, a very rich and powerful frame/object system. The main research focus was flexibility: to allow experimentation with object models in order to find an optimal object kernel for SK8. MacFrames was so flexible that by setting a myriad of preferences it could be used to emulate a large variety of object systems. This research, in concert with users developing actual applications and prototypes at Apple, yielded the simple and elegant model that is in SK8 today.

With this version of the object system in place, we started to work on the graphics and UI side of the system. The early SK8 graphics system used a metaphor slightly extending HyperCard (e.g., cards but with multiple layers instead of single fixed backgrounds). Around this time, the original version of SK8Script, a prototype for the first specification of the AppleScript language, was extended to a fully object-oriented scripting language based on the SK8 object model. At this time, a number of people in the Advanced Technology Group began to use SK8 for their projects, providing timely and intimate suggestions to improve the system. Certain universities and corporation fans began to participate: they either used SK8 as a research tool or examined it to provide detailed feedback to us.

In 1992 and 1993, to incorporate the necessary design changes while maintaining the system's elegance, we re-implemented SK8 from the ground up, resulting in the current SK8 architecture. The object system was reimplemented by manipulating the internals of the Macintosh Common Lisp CLOS (Common Lisp Object System) intrinsics. The card based metaphor was finally discarded for the more general graphical containment approach. The SK8Script syntax was completed and the compiler and runtime performance improved. The SK8 Project Builder was created to provide a very rich set of direct manipulation tools, including tools for building browsers through direct manipulation. An object store was added to the system.

Since then, aspects of the system have continually been redesigned to try to reach a deeper level of elegant simplicity and integration. Such work can never be finished: the system is comprehensive and rich. There is always another area to improve, another piece of functionality to provide, another kludge to remove. And although there are many parts of the system which remain unpolished or unfinished, we are proud of the number of innovations and ideas that are part of the system. We hope you enjoy them, too.

About the SK8 Painting

SK8 is unique among authoring systems in that it has its very own painting, called "Still life with SK8". The SK8 painting can be seen every time SK8 starts up, playing the role of the SK8 splash screen. It has also acted as the cover of SK8 CD releases.

The painting was done by Elizabeth Gomez-Freer and is now the property of Ruben Kleiman. It is painted on a square, 25" by 25", canvas using oil paint. It was completed in 1993.

What's New | Find It | Apple Computer, Inc. | Contact Us | Help