December 2008

Zorap, Web-Based Video Chat

Zorap web pages are multi-party multimedia environments. Video from your webcam and audio from your microphone, photos, music and video from your own computer are shared to tens of your friends via a Zorap Server. Web content, including YouTube and other video sites are similarly shared, all in an exciting and customizable drag-and-drop interface.

Electric Magic implemented the Mac-specific portions of the Zorap web plugin, supporting Safari, Firefox and other modern web browsers.

May 2006

Knowledge Forum 4.6

Knowledge Forum 4.6's minor version number change belies just how different from its predecessor it really is.

Under the hood KF 4.6 has moved from using ZDBase for its backing store, instead using a tuplebase. This makes it possible to split HTML page generation into separate processes, potentially running on multiple front end machines. It also restores support for a rich client application, now written in Java, using ZTSoup to efficiently communicate changes in the tuplebase, whether made by other clients or by the web interface.

January 2006


WebDAV is an extension to the HTTP protocol. It is the basis for Apple's iDisk and Windows' Web Folders, standard features of Mac OS X and Windows XP. It is thus the easiest way for a server to make data available to a client machine without requiring that client software be installed first.

ZooLib provides a generic WebDAV server. Your application need only implement subclasses of ZNodeRep to represent nodes in your desired hierarchy. Standard subclasses of ZNodeRep let you lay one tree over another, or expose part of the server's file system to clients.

Frankly, WebDAV is an inelegant protocol. It puts some information in the URL, some in header lines, and some is encoded as XML in the body of requests and responses. But it has three sterling characteristics:

  • It exists
  • It works
  • It's usable out of the box on Mac, Windows and many flavors of UNIX

August 2003

Knowledge Forum 4.5

Knowledge Forum 4.5 was a significant refinement of Knowledge Forum 4.0, with a much richer web interface, although still constrained by the need to support Netscape 4.x-era web browsers.

New features included support for upload and download of files as attachments to views and notes, headings within views, full text and attribute-based searches, and notification by email. It also supported graphs of useful metrics, implemented across platforms using ZDC_ZooLib.

On the back end, a significant change was moving from the original blockstore implementation to one based on B+Trees that uses a neat upward propagting copy-on-write of nodes to make it virtually bullet-proof - only a physical failure of the backing store can cause data loss.

November 2002

Web Browser Plugins

ZooLib's UI code requires only that there be a ZFakeWindow-derivative at the top of the enclosure hierarchy. In the distant past ZooLib included implementations of ZFakeWindow for Mac control panel cdevs, HyperCard XCMD windows, MacroMind Director XObject windows, Zoom closures, MacApp views and of course still does for ZOSWindows.

It was thus relatively straightforward to implement ZFakeWindow_NSPlugin, which translates between the Netscape browser plugin and the ZFakeWindow APIs. What was actually more difficult was finding a decent implementation of the plugin glue code and header files. In 2002 there wasn't anything that would work with current compilers and with current browsers, so most of the effort was in putting together ZNSPlugin, which is a usable implementation of the glue.

September 2002

Knowledge Forum 4.0

Knowledge Forum 4.0 took the radical direction of being web-only. We'd had some support for web access by virtue of a perl program that used the client's communications protocol to talk directly to the server, but perl wasn't pre-installed on Mac OS (Classic) or Windows, and it had some performance problems. So we ported the perl software to C++ and incorporated it into the server directly.

For a time we had native client and web access running simultaneously, but never in a released version. The 3.x client remains buildable as of May 2006, but still talks only to a 3.x server.

December 2000


ZooLib is an Open Source (MIT License) C++ library that makes it easy to write one set of source and build an application for Windows, Mac and UNIX. It provides a foundation suite of facilities that in essence form a virtual operating system API, and wide range of higher-level facilities that build on that foundation.

ZooLib abstracts threads, files, networking, graphics and the user interface. And there are escape hatches whereby OS-specific features can be accessed without compromising the platform-agnostic nature of the rest of the code.

ZooLib has been under continual development since 1992, and incorporates fixes for every OS bug or anomaly I've encountered, and generally provides cleaner mechanisms for most tasks than OSes traditionally provide. It's been the basis of Measurement in Motion, NetPhone, and every version of the Knowledge Forum server and client applications.

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