ch 7

Question 1

acceptance

Answer 1

When an organization decides to accept a risk because the cost of avoiding the risk outweighs the potential loss of the risk. A decision to accept a risk can be extremely difficult and controversial when dealing with safety-critical systems because making that determination involves forming personal judgments about the value of human life, assessing potential liability in case of an accident, evaluating the potential impact on the surrounding natural environment, and estimating the system’s costs and benefits.

Question 2

agile development

Answer 2

A software development methodology in which a system is developed in iterations lasting from one to four weeks. Unlike the waterfall system development model, agile development accepts the fact that system requirements are evolving and cannot be fully understood or defined at the start of the project.

Question 3

annualized loss expectancy (ALE)

Answer 3

The estimated loss from a potential risk event over the course of a year. The following equation is used to calculate the annual loss expectancy: A× SLE = ALE. Where ARO is the annualized rate of occurrence, an estimate of the probability that this event will occur over the course of a year and SLE is the single loss expectancy, the estimated loss that would be incurred if the event happens.

Question 4

annualized rate of occurrence (ARO)

Answer 4

An estimate of the probability that a risk event will occur over the course of a year.

Question 5

avoidance

Answer 5

The elimination of a vulnerability that gives rise to a particular risk in order to avoid the risk altogether. This is the most effective solution but often not possible due to organizational requirements and factors beyond an organization’s control.

Question 6

best practice

Answer 6

A method or technique that has consistently shown results superior to those achieved with other means and that is used as a benchmark within a particular industry.

Question 7

black-box testing

Answer 7

A type of dynamic testing that involves viewing the software unit as a device that has expected input and output behaviors but whose internal workings are unknown (a black box).

Question 8

breach of warranty

Answer 8

When a product fails to meet the terms of its warranty.

Question 9

business information system

Answer 9

A set of interrelated components—including hardware, software, databases, networks, people, and procedures—that collects and processes data and disseminates the output.

Question 10

Capability Maturity Model Integration (CMMI) models

Answer 10

Collection of best practices that help organizations improve their processes.

Question 11

CMMI-Development (CMMI-DEV)

Answer 11

A specific application of CMMI frequently used to assess and improve software development practices.

Question 12

decision support system (DSS)

Answer 12

A type of business information system used to improve decision making in a variety of industries.

Question 13

dynamic testing

Answer 13

A QA process that tests the code for a completed unit of software by actually entering test data and comparing the results to the expected results.

Question 14

failure mode

Answer 14

A description of how a product or process could fail to perform the desired functions described by the customer.

Question 15

failure mode and effects analysis (FMEA)

Answer 15

An important technique used to develop ISO 9000-compliant quality systems by both evaluating reliability and determining the effects of system and equipment failures.

Question 16

hazard log

Answer 16

A logging and monitoring system used by safety engineers to track hazards from a project’s start to its finish.

Question 17

high-quality software system

Answer 17

Systems that are easy to learn and use because they perform quickly and efficiently; they meet their users’ needs; and they operate safely and reliably so that system downtime is kept to a minimum.

Question 18

integration testing

Answer 18

Software testing done after successful unit testing, where the software units are combined into an integrated subsystem that undergoes rigorous testing to ensure that the linkages among the various subsystems work successfully.

Question 19

ISO 9001 family of standards

Answer 19

A set of standards written to serve as a guide to quality products, services, and management. It provides a set of standardized requirements for a quality management system.

Question 20

N-version programming

Answer 20

An approach to minimizing the impact of software errors by independently implementing the same set of user requirements N times (where N could be 2, 3, 4 or more); the N-versions of software are run in parallel; and, if a difference is found, a “voting algorithm” is executed to determine which result to use.

Question 21

product liability

Answer 21

The liability of manufacturers, sellers, lessors, and others for injuries caused by defective products.

Question 22

quality assurance (QA)

Answer 22

Methods within the development process that are designed to guarantee reliable operation of a product.

Question 23

quality management

Answer 23

The defining, measuring, and refining of the quality of the development process and the products developed during its various stages. The objective of quality management is to help developers deliver high-quality systems that meet the needs of their users.

Question 24

redundancy

Answer 24

The provision of multiple interchangeable components to perform a single function in order to cope with failures and errors.

Question 25

reliability

Answer 25

A measure of the rate of failure in a system that would render it unusable over its expected lifetime

Question 26

single loss expectancy (SLE)

Answer 26

The estimated loss that would be incurred if a risk event occurs.

Question 27

software defect

Answer 27

Any error that, if not removed, could cause a software system to fail to meet its users’ needs.

Question 28

software development methodology

Answer 28

A standard, proven work process that enables systems analysts, programmers, project managers, and others to make controlled and orderly progress in developing high-quality software.

Question 29

static testing

Answer 29

A software-testing technique in which software is tested without actually executing the code. It consists of two steps—review and static analysis.

Question 30

strict liability

Answer 30

A situation in which the defendant is held responsible for injuring another person, regardless of negligence or intent.

Question 31

system safety engineer

Answer 31

Someone who has explicit responsibility for ensuring that a system will operate in a safe and reliable manner while meeting its users’ needs.

Question 32

system testing

Answer 32

Software testing done after successful integration testing, where the various subsystems are combined to test the entire system as a complete entity.

Question 33

transference

Answer 33

A risk management strategy in which the risk, should it happen, does not rest solely on one individual or organization. For example, a common way to accomplish risk transference is for an individual or an organization to purchase insurance, such as auto or business liability insurance. Another way to transfer risk is to outsource the risk by contracting with a third party to manage the risk.

Question 34

unit testing

Answer 34

A software-testing technique that involves testing individual components of code (subroutines, modules, and programs) to verify that each unit performs as intended.

Question 35

user acceptance testing

Answer 35

Software testing done independently by trained end users to ensure the system operates as expected.

Question 36

waterfall system development model

Answer 36

A software development methodology that involves a sequential, multistage system development process in which development of the next stage of the system cannot begin until the results of the current stage are approved or modified as necessary.

Question 37

white-box testing

Answer 37

A type of dynamic testing that treats the software unit as a device that has expected input and output behaviors but whose internal workings, unlike the unit in black-box testing, are known.