CS 5380 Software Engineering Chapter 11 Dependability and Security.
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Transcript of CS 5380 Software Engineering Chapter 11 Dependability and Security.
S
CS 5380 Software Engineering
Chapter 11 Dependability and
Security
Section 2
Section2 Dependability and Security Ch 10 SocioTechnical Systems Ch 11 Dependability and Security
Chapter 11 - Dependability and Security
Objectives – Chapter 11
First page of chapter
Chapter 11 - Dependability and Security
Dependability
Several topics Availability Reliability Safety Security
Each has further subtopics
Chapter 11 - Dependability and Security
Problem based learning
Student takes responsibility for learning
Solution of a problem is the foundation for learning the key principles
Different from Lecture Lecture/application of principles
Chapter 11 - Dependability and Security
Availability
Probability that a system is up and working
Measurement Max time down per instance Max number of times down Percentage of time down
May vary with time of day / day of week Allow for nighttime maintenance
System may have multiple measurement points
Can involve many aspects Hardware, network, power, OS, maintenance,
Affected by system loadChapter 11 - Dependability and Security
Availability
Real time systems (robotics, automotive)
Control systems (industrial)
Embedded (printers, medical equipment)
Communications (phone, network)
Financial
Chapter 11 - Dependability and Security
Reliability
Probability of failure free operation
Measurement Time between failures Failure per transaction Failures per time
Depends heavily upon the operation Multiple values
Depends on data Different types of data exercise different aspects of sotware
Chapter 11 - Dependability and Security
Reliability
Real time systems (robotics, automotive)
Control systems (industrial)
Embedded (printers, medical equipment)
Communications (phone, network)
Financial
Chapter 11 - Dependability and Security
Safety
Never harm people or property
Even if system fails to operate Power, network, hardware, system load
Primary vs Secondary Insulin Pump CAD
Author: Malfunctions often related to requirements specification
Hardware failure consideration
Chapter 11 - Dependability and Security
Safety
Hazard avoidance Car navigation system – disabled when vehicle
moving
Hazard detection Pressure, temperature, speed sensors Car – distance sensor
Damage limitation Insulin pump – manage failure of sensor.
Chapter 11 - Dependability and Security
Security
Protection from threats Intentional Unintentional
Unintentional Tsunami/earthquake
Chapter 11 - Dependability and Security
Security
Security from Modification Theft
Layers of Protection Networking Logon Authentication Limitation of data access
Chapter 11 - Dependability and Security
Security Terminology
Assets
Exposure
Vulnerability
Attack
Threat
Control
Chapter 11 - Dependability and Security
Dependability
Repairability Trace of activities Error logs / meaningful errors
Maintainability Much software evolves
Survivability Resistance to attack Threat identification
Error Tolerance
Chapter 11 - Dependability and Security