Question

Describe examples of the same for software systems. • How can the degree of reliability be measured? • What engineering is necessary to detect a exception (a failure to operate normally)? • What is the goal of an exception handler?

Answer 1

Reliability is the degree to which an assessment tool produces stable and consistent results. Reliability refers to the consistency of a measure. Four most common approaches of measuring reliability for any empirical method or metric is belew test-retest reliability • parallel forms reliability • inter-rater reliability Internal consistency reliability In terms computer science it is an different approach as below we can measure reliability as a combination of two important measurements: Mean Time Between Failures (MTBF) and Mean Time to Repair (MTTR). Mean Time Between Failures (MTBF) is the measurement of time between system breakdowns, but it only includes the time the system is working and not being worked on). A system that had been running strong for a year may suddenly have two down times in a one-month period; this will drag down MTBF. It should also warrant discussion on what updates/patches may have been missed during those long stretches of uptime. Mean Time to Repair (MTTR) is the number you use to measure the average time it takes to fix a system

Engineering neccesary to detect an exception Fault tolerance is the property that enables a system to continue operating properly in the event of the failure of (or one or more faults within) some of its components. Fault tolerance on a system is a feature that enables a system to continue with its operations even when there is a failure on one part of the system. The system can continue its operations at a reduced level rather than be failing completely For example, Amazon Web Services (AWS) provides a platform that is ideally suited for building fault-tolerant software systems. The AWS platform enables you to build fault-tolerant systems that operate with a minimal amount of human interaction and up-front financial investment

Goal of exception handler The goal of exception handler is to handle the exception normally without crashing the application An exception handler is code that handles the error normally that is caught and stops the program with an error message and avoids program crash. Exception handling ensures that the flow of the program doesn't break when an exception occurs. For example, if a program has a bunch of statements and an exception occurs mid way after executing certain statements, then the statements after the exception will not execute and the program will terminate without crashing. Exception handling is the method of building a system to detect and recover from exceptional conditions. Exceptional conditions are any unexpected occurrences that are not accounted for in a system's normal operation. It is difficult to protect a system from the effects of exceptional conditions because, by nature, all unusual occurrences cannot be anticipated when the system is designed. Some examples of exceptional conditions are incorrect inputs from the user, bit level memory or data corruption, software design defects that cause a system to enter an undefined state, and environmental anomalies. If these exceptional conditions are not properly caught and handled, they can cause an error or failure in the system.