Chapter 14 - Quality Attribute Modeling and Analysis

Question 1

what is an analytic model

Answer 1

a model for quantitative describing how well an architecture performs with respect to some quality attribute

Question 2

5 components of performance models

Answer 2

• arrivals
• queue
• server (scheduling alg)
• routing of messages
• results

Question 3

8 performance model parameters

Answer 3

• arrival rate of events
• chosen queuing discipline
• scheduling alg
• service time for events
• network topology
• network bandwidth
• routing alg

Question 4

the cost of performance modeling?

Answer 4

determining/estimating the parameters

Question 5

the benefit of performance modeling

Answer 5

estimate of the latency

Question 6

When should or shouldn’t performance modeling be done

Answer 6

• SHOULD when latency is important

- SHOULD NOT if there is obviously sufficient capacity to satisfy demand

Question 7

2 parameters for availability modeling

Answer 7

• failure rates of components

- recovery time of components

Question 8

Basic probabilities to know

Answer 8

P(A and B) = P(A)*P(B)

P(A or B) = P(A) + P(B) - P(A and B)

Question 9

2 main purposes of a quality attribute checklist

Answer 9

• checking requirements

- auditing

Question 10

2 aspects of a checklist

Answer 10

• product requirements

- process requirements

Question 11

Intellectual basis of availability models

Answer 11

markov/statistical models

Question 12

Intellectual basis of interoperability models

Answer 12

conceptual framework

Question 13

Intellectual basis of modifiability models

Answer 13

-coupling an cohesion metrics

Question 14

Intellectual basis of performance models

Answer 14

queuing theory and real time scheduling theory

Question 15

Intellectual basis of testability models

Answer 15

component interaction metrics

Question 16

7 ways to analyze quality attributes

Answer 16

• analytic models
• checklists
• thought experiments
• back-of-the-envelop analysis
• experiments
• simulations
• prototypes

Question 17

What are the steps in thought-experiment analysis

Answer 17

• enumerate the steps of a use case
• at each step consider the mechanism being implemented to support a given quality requirement
• consider if the identified mechanism hinders the achievement of other quality attribute requirements
• record issues for later

Question 18

what is back-of-the-envelope analysis

Answer 18

rough and non-precise analysis that can provide general understanding

Question 19

2 types of tools that can help to perform experiments

Answer 19

request generators: create synthetic loads to test for scalability

monitors: perform non-intrusive resource usage detection

Question 20

The main use for prototypes?

Answer 20

to explore design options

Question 21

what are event-based simulators?

Answer 21

are used to simulate behavior of a system under various loads

Question 22

which 3 forms of analysis are used in requirements?

Answer 22

-analytic models and back-of-the-envelope to plan for capacity

checklists to ensure the requirements are correct

Question 23

which 4 forms of analysis are used in design?

Answer 23

• prototypes
• analytic models and simulations to understand bottlenecks
• checklist to determine if correct mechanism used

Question 24

which form of analysis are used in implementation?

Answer 24

-experiments

Question 25

which 2 forms of analysis are used after fielding?

Answer 25

• experiments

- monitors to determine actual behavior