Overview of The Concurrent Development Model

The concurrent development model, sometimes called concurrent engineering The concurrent process model can be represented schematically as a series of major technical activities, tasks, and their associated states.
It makes use of state charts to represents the concurrentrelationship among tasks associated within a framework of activities. It isrepresented schematically by a series of major technical tasks, and associated states. The user's need, management decisions and review results drive theover-all progression of the development.

The concurrent model is often more appropriate for system engineering projects where different engineering teams are involved. The concurrent process model defines a series of events that will trigger transitions from state to state for each of software engineering activities, actions or tasks. This generates the event analysis model correction which will trigger the analysis action from done state to awaiting changes state.

The concurrent process model is applicable to all types of software development and provides an accurate picture of the current state of a project. Rather than confining software engineering activities, actions and tasks to a sequence of events, it defines a network of activities. Each activity on the network exists simultaneously with other activities, actions or tasks. Events generated at one point in the process network trigger transitions among the states.

Testing for Real-Time Systems - Effective Strategy for testing real time systems

The nature of real time systems is time-dependent and its asynchronous nature. This nature adds a difficult element to the testing mix and that is time. Test case designer need to consider:
- event handling
- timing of the data
- parallelism of the tasks that handle the data
The intimate relationship between real time software and its hardware environment causes testing problems.

An effective four step strategy for testing a real time system are:
Task Testing:
The first step is to test each task independently. Each task has conventional tests designed for them and each task is executed. It helps to uncover errors in logic, function.
Behavioral Testing:
The behavior of a real time system can be simulated using system models created with automated tools. These analysis activities can serve as the basis for the designing of test cases.
Intertask Testing:
Once the task and system related errors are identified, asynchronous tasks that communicate with one another with different data rates and load are tested against errors. Tasks that communicate through a message queue or data store are tested to uncover errors.
System Testing:
System tests are done to uncover errors at the software/hardware interface. Testing the handling of boolean events is essential. The tester develops a list of possible interrupts using state diagram and control specification. Tests that are designed are:
- Interrupt priorities are properly assigned and handled?
- Processing for interrupt is correct?
- Does performance procedure conform to requirements?
- Does high volume of interrupts arriving at critical times create problems in performance?