StateWORKS Newsletter 3/06


  1. Welcome
  2. The technical note "Lifetime and events"

1. Welcome

At last, the book "Modelling Software with Finite State Machines: A practical approach" has been printed and is available in several on-line book stores, as well as directly from the publisher. We have already announced its publication. I would like to remind you only that the purchase of the book will entitle the buyer to get the registration key for use of StateWORKS Studio LE without a time limit. We attach the electronic version of a book flyer prepared by the publisher. It is linked to the CRC Web site. Simply clicking on the book's title or the order form on the flyer will take you to the CRC site where you can quickly and easily see the details and place an order.

The lifetime of control signals is a topic which must be well understood when using the StateWORKS run-time systems. This is a topic of the technical note "Life time and events" which discusses in addition the closely related topic of generation of events by RTDB objects.

F. Wagner

2. The technical note "Life time and events"

If a specification of a state machine is just an informal diagram which expresses the general intention, but the details are solved later in the code we need not bother about implementation details while specifying the state machine: a programmer will do it.

On the other hand, using an RTDB based execution system operating with powerful objects requires a good understanding of the execution model. In addition, the VFSM concept of static virtual input demands from the designer some decisions about the life-time of consumable signals.

RTDB objects generate events if their values change. All clients are notified by events which trigger also the state machine executor. That mechanism must be well understood if we want to specify efficiently state machines and systems of state machines.

These topics are discusses in the technical note "Life time and events".