Real Time Systems

1
Real Time Systems

• An overview of the RoseRT Services Library
  Framework

2
Outline

• Framework
• real-time services
• code generation
• ObjecTime / ROOM terminology
• Capsules
• Ports

3
The RoseRT Framework

• recall that a framework is an inverted library
• provides a skeleton of a real-time application
• messaging
• timing
• dynamic structure
• event-based processing
• platform independence
• the developers job is to fill in skeleton
• classes, capsules and protocols
• state machine specific behavior

4
The RoseRT Framework

• powerful code generation capability
• user defined UML notations along with user
  provided state machine action codes get converted
  to C and integrated with the frameworks
  real-time system services.
• Effective use of the tool requires
• understanding the basic design of the framework
• understanding the implementation of the 5 main
  services (their classes and methods)

5
The RoseRT Framework

• Terminology translation from ROOM to UML
• actor capsule instance
• actor reference capsule role
• actor class capsule
• SAP unwired protected port for accessing a
  service (service access port)
• SPP unwired public port for providing a service
  (service provider port)

6
Capsules

• capsule instances become subclasses of RTActor
• RTActor contains the state machine processing and
  the message behavior used by all capsules
• sample operations getMsg(), getError(),
  getIndex(), getName()
• capsule instances have access to RTMessage
  objects through msg
• sample RTMessage operations getData(),
  getSignal(), getPriority(), reply()
• capsule instances have access to their controller
  object (through context)

7
Capsules

• capsule class information is kept separate from
  RTActor instances in RTActorClass metaclass
• for example the interface ports
• capsule roles are attributes of RTActorRef
• RTActorRef has only one public operation and it
  is size( ), used to determine the capsule
  cardinality
• capsule roles are place holders for zero or more
  capsule instances
• replicated capsule roles

8
Ports

• ports are Protocol type attributes in RTActor
  subclasses
• the port attribute will be a subclass of the
  common base class, RTProtocol
• sample RTProtocol operations registerSAP/SPP()
  recall(), purge(), size() ...
• RTProtocol depends on three types of signals
  RTInSignal, RTOutSignal and RTSymmetricalSignal
• Timing, Log, Exception and Frame ports are
  subclasses of RTProtocol
• protocols become 2 classes - base conjugate

9
Ping Pong Example
/pong
/ping
/talk
/talk
ltltport1gtgt
ltltport1gtgt