communicating concurrent processes used in graphical Shen

[Mark Tarver]

Still a substantial amount of time is going into providing Shen Professional with graphics and the implementation will use the communicating concurrent process (CCS) model introduced in SP 5.0 in February.  So the various pieces of SP are starting to work together and this is my first serious experience working with CCS.  The style of programming requires considering how events may interact.  This is not true of the simple or restricted theory which Willi used to gain the 5X speedup for his primes program - this used non-communicating parallelism.  Understanding the importance enabled me to gain a grasp on some odd bugs (to do with background processes eating data) and eliminate them.  It certainly is a different way of thinking.   I now have more sympathy with those programmers working with real time avionics systems which must be vastly more complex.    

Anyway news is; the system is developing well.  This is likely to be a long term project because TCL/tk is vast.  Expect delivery around July-August and continuing upgrades as more and more of TCL/tk is placed under Shen and sequent calculus.    I'll place a few screen videos on this.

Mark