exam 4 Flashcards
What is the definition of a (web) service
A loosely coupled, reusable software component that encapsulates discrete functionality, which may be distributed and programmatically accessed
List 4 benefits of using a service-oriented approach to software engineering.
Services can be offered by any service provider
info about the service public
Applications can delay the binding of services
new services is possible thru linking existing ones in new ways
Service users can pay for services according to their use rather than their provision
What is service engineering and what are the key service engineering process stages?
The development of dependable, reusable services
Identifying candidate services
Define interface and implement
Test and deploy
What is a workflow (related to service-oriented SE)?
logical sequences of activities that, together, model a coherent business process
For example, provide a travel reservation services which allows flights, car hire and hotel bookings to be coordinated
What are the six stages in service construction by composition?
formulate outline workflow
discover services
select possible services
refine workflow
create workflow program
test completed service or application
What is the difference between a technical and a sociotechnical system?
Technical computer-based systems include hardware and software but not humans or organizational processes
Sociotechnical systems include technical systems plus people who use and manage these systems and the organizations that own the systems and set policies for their use
What are the four principal stages of systems engineering?
conceptual design
procurement or acquisition
development
operation
What are three influences on the reliability of a system?
hardware reliability
software reliability
operator reliability
What five activities are part of the conceptual design process?
concept formulation
problem understanding
system proposal development
feasibility study
system structure development
What are the five main drivers for system procurement decisions?
The state of other organizational systems and whether or not they need to be replaced
The need to comply with external regulations
External competition
Business re-organization
Available budget
What are the five main factors (including costs) that influence the lifetime of a system?
loss of expertise
replacement cost
return on investment
risks of change
system dependencies
List 5 important characteristics of embedded systems that differentiate these systems from other types of computer system.
run continuously
interactions with system’s envi are unpredictable
physical limitations that affect system design
direct hardware interaction
issues of safety & reliability
What are the two types of stimuli that must be handled in a real-time system?
periodic
aperiodic
What is a circular buffer and how is it used in real-time systems?
Producer processes collect data and add it to the buffer. Consumer processes take data from the buffer and make elements available.
The buffer must stop producer processes adding information to a full buffer and consumer processes trying to take information from an empty buffer.
Why are state machine models used in the design of embedded real-time software processes?
The effect of a stimulus in a real-time system may trigger a transition from one state to another
