Building Tcl-Tk GUIs for HRT-HOOD systems

This work explores Tcl-Tk 8.0 as a building tool for script-based GUIs in Ada95 real-time systems. Tcl-Tk 8.0 is a library that makes graphic programming easier, but it suffers from being non-thread-safe. An application architecture is proposed, the deferred server, which provides transparent use of Tcl-Tk to multithreaded Ada95 applications via TASH, a thick binding that allows Ada95 single-threaded code to use Tcl-Tk. We find that only a minimal extension to Tcl-Tk 8.0 and TASH is required to support it, while a successful prototype has been implemented based on these ideas. Likewise, the early integration of Tcl-Tk graphic user interfaces in HRT-HOOD designs is examined; unfortunately, in this respect, we conclude that this is not feasible. However, a HRT-HOOD conform distributed configuration is outlined in wich the user interface becomes a multithreaded remote service based on the deferred server architecture.