March 2008

Mac/BlackBerry SDK

The BlackBerry is a very popular mobile communications device. Official Mac support from Research in Motion is limited to providing the PocketMac utility as a free download. With no official SDK the Mac/BlackBerry ecosystem has seen very little activity.

ZBlackBerry is a suite of code that implements the BlackBerry USB communications protocol in a generic fashion. A few hundred lines of code let Macs use that protocol. A few hundred more allow multiple Mac applications to talk to a single BlackBerry simultaneously, something that has not been possible till now.

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January 2008

iMobimac Modem

The Research In Motion Blackberry is famous for its connectivity. iMobimac Modem runs on a Blackberry and the Mac to which it is connected, and lets Mac applications access the Internet using the Blackberry's connection.

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October 2007

Embedding Lua in Zen

Lua is a very nice little programming language, which combines a clean C-ish syntax with the power of Scheme. Rather than requiring a particular programming style it provides building blocks that allow one to work in any combination of object-oriented, functional or imperative styles. Lua is something of a hidden gem, having found a keen but un-publicized audience amongst game developers who generally use it for scripting in-game behavior. My interest in it is to provide customizability of behavior in the Zen home automation system.

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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.

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.

October 2002

Tuplebase

ZooLib's tuplebase is derived from the tuplespace concept initially explored in the Linda coordination language, another well known derivation of which is Sun's JavaSpaces system. Whereas JavaSpaces is Java-only and relies on many of that languages's features, ZooLib's tuplebase works today with C++ and Java, and is well suited to work with other languages.

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October 2002

ZDC_ZooLib: Portable Graphics

ZooLib defines and implements a graphics API that produces identical results across all supported platforms. It is geared towards creating user interface elements and so is pixel-based rather than geometric so that a programmer can know precisely which pixels will be touched by a drawing operation. It supports pixel-plotting, lines of any thickness, text, rectangles, rounded rectangles, ovals, arbitrary regions and the drawing of masked-pixmaps. ZDC_ZooLib is an implementation of this API using no OS facilities at all, and thus can be used in server applications without the difficulties that normally poses (gaining access to a window or graphics server from a low-privilege process).

The implementation uses operations on ZBigRegion instances to decide which pixels to touch, decomposes the regions into rectangles and then calls ZDCPixmapBlit to actually do the work.

June 2001

BlockStore: File System in a File

Applications often have to satisfy two conflicting requirements. On the one hand the data created by a user has a structure whose parts should be managed independently of one another, ideally with each piece placed in its own file. On the other hand users like to think of their data as a single entity which can be copied, emailed and backed up in its entirety. Although Mac OS X has the notion of a bundle, a specially marked directory which behaves like a single file when manipulated by the Finder, other operating systems do not.

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March 2001

Assets: Portable resources

I picked the name 'asset' as an alternative to 'resource', a term that already has too many disparate meanings on different platforms. That said, assets are used in the same situations that MacOS/Win32/BeOS resources would be, although the mechanism is more flexible.

The data making up an asset tree is directly usable by any processor, big or little-endian. It can be kept in a file, loaded into RAM, memory-mapped from disk or accessed from a stream.

December 2000

ZooLib

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.

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August 1999

NPainter

NPainter is a suite of classes that provides a MacPaint-like interface, but supporting indexed and true color, across all platforms supported by ZooLib.

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January 1998

ZFiber: Threads At Interrupt Time

Fibers, at least in this context, are threads implemented using setjmp/longjmp to transfer control in a manner reminiscent of co-routines. They are a generalization of the stack-swapping used by NetPhone to run in the constrained environment it experienced when its deferred tasks were scheduled when an application with a tiny stack was current (yes Print Monitor, I'm talking about you).

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January 1995

NetPhone

In 1994 the Internet was just starting to be available in people's homes and offices. NetPhone was the first application to support what's now known as VOIP (Voice Over IP) without requiring a high-speed connection.

January 1994

Measurement in Motion

Measurement in Motion is a pioneering math and science analysis and investigation tool. It lets students take measurements from real-world video footage, then tabulate, graph and derive secondary measurements from their data. Conversely, students can generate data algorithmically and superimpose it over video to provide visceral confirmation of hypothesized behavior.

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