Visual Formal Methods R J Walters

Introduction Motivation The Language The tools An example Conclusion

Issues in large systems Connecting the parts Getting the result to make sense

RDT Draw your processes (components) Draw how they are connected Run the model in the execution tool Use a model checker on it - SPIN * Limitations are accepted in exchange for ease of use

RDT: Processes Process has state Displayed as a picture Built using system of dialogue boxes 3 types of event –Receive –Send –Create

RDT: Events, Receive

RDT: Events, Send

RDT: Events, Create

An example process

RDT: Models Add instances of processes to your model Describe how these instances are (initially) connected

Models: Process Instances

Models: Connections

Example model

What next? Execute the model Use a model checker on it

Channels: Communication in RDT is founded on the pi-calculus Similar identity between values and channels RDT also permits asynchronous communication –Need channels in the execution tool

Executing the model Each Process instance has a window which shows: –Name and type –State –List of available actions –List of local channel names mapping these to instances of channels

Executing the model Each Channel (instance) has a window which shows: –Name –List of values held in the channel

The Execution tool

RDT: Conclusion Language, model construction tool, execution tool, translation tool Builds formal models using “informal” methods