Book Review: The Power of PenPoint

The Power of PenPoint Strikes a Good Compromise

A good place to start your exploration of pen-based computing technology is with Robert Carr and Dan Shafer’s book, The Power of PenPoint (Addison-Wesley, 1991). This new book, co-authored by the architect of GO’s PenPoint operating system, Robert Carr, strikes a good compromise between technical detail and general information, providing both prospective developers as well as curious observers with an excellent introduction to the concepts behind PenPoint in particular and pen-based technology in general. The book is similar to Gordon Letwin’s Inside OS/2 (Microsoft Press), in that it represents an introduction to a new operating system by its chief architect.

Not a Line of Code

As the book’s introduction states, there is not a single line of sample code in The Power of PenPoint. The emphasis is on concepts and the general techniques for implementing those concepts rather than on the specifics of writing code. Although there is no sample code, there are plenty of diagrams and PenPoint screen shots to illustrate the key features and concepts behind PenPoint. And the lack of code does not imply a lack of technical thoroughness. The book covers in detail technical topics such as the pre-emptive multitasking and object oriented messaging systems used in PenPoint. As a further example, the book looks in detail at the embedded document architecture (EDA) of PenPoint and gives developers guidelines on how to develop their applications to work successfully within EDA.

The book starts out with an overview of the requirements of a pen-based system, and how these requirements differ from those of a traditional desktop computing environment. The discussion covers issues such as mobile computing and the new tasks and interfaces required by this type of computing — detachable networks, handwriting recognition, new hardware requirements, and the rationale behind designing a new operating system.

The book then moves right into the concepts of PenPoint, with a look at the notebook user interface and the concept of “ink as a data type,” followed by an introduction to developing software for PenPoint and the software development kit (SDK). Following chapters include details on the PenPoint kernel and windowing system, the application framework and the embedded document architecture, the ImagePoint graphics and imaging system, the user interface toolkit, the file system, and chapters on resource management and connectivity.

Appendices include a list of the important data structures, classes, and messages supported by PenPoint. A separate appendix covers handwriting recognition and criteria for evaluating the accuracy and speed of various handwriting recognition systems. The book ends with a comprehensive glossary of PenPoint terms and a topic index.

Required Reading

The Power of PenPoint is certainly not a programmers’ manual or a “how to” book for PenPoint software developers. But it provides an excellent overview of PenPoint and should be considered required reading for anyone contemplating PenPoint software development. In addition, it is useful to general readers interested in the technical issues and concepts underlying pen-based computing.

The Power of PenPoint, by Robert Carr and Dan Shafer
Addison-Wesley, 1991
(ISBN 0-201-57763-1)
Paperback, 342 pages
$22.95