Maisie/PARSEC

Message-based, process-interaction approach

LP: programmed as an actor or entity
- all activities of an entity initiated on message receipts
- An LP cannot directly modify the state of another LP (only via messages) (encapsulation)

event: represented by message communications
- e(t,p,a): send message m(e) at time t to LP p

on receiving m(e), p executes actions a
- change its state (local variables)
- schedule events(messages) at time >=t
- unschedule previously scheduled events (e.g. timeout) ;