1. Reliability Andy Jensen Sandy Cabadas

2.  Understanding Reliability and its issues can help one solve them in relatable areas of computing Thesis

3.  What is Reliability?  Understanding differences between similar terms  Challenges of Reliability & How to Solve Them  Topics Impacted by Reliability Outline

4.  Reliability is the capability of a person or system to be able to perform and maintain its functions in any scenario given  The capacity of a designed, produced or maintained item to perform as required over time  The resistance to failure of an item over time Reliability

5.  Tries to avoid:  Anything going wrong  Inconsistencies  Tries to accomplish  Meeting requirements  Convenience Reliability

6.  Reliability is a process of many  Just a few…  Systems  Computer networks  Data  Engineering Dependents

7.  What is Reliability?  Understanding differences between similar terms  Challenges of Reliability & How to Solve Them  Topics Impacted by Reliability Outline

8.  Reliability  Expected time until incorrect service  System to perform and maintain its functions in routine circumstances, as well as hostile or unexpected circumstances.  Availability  % of time delivering correct service  Stability  the quality of being enduring and free from change or variation  Dependability  Measure of systems reliability, availability, and maintenance support Understanding the Differences

9.  Validity: Measuring what a system is supposed to do  Reliability: Getting the same results every time for a certain test  Reliability doesn’t matter if the test isn’t valid Reliability and Validity

11.  What is Reliability?  Understanding differences between similar terms  Challenges of Reliability & How to Solve Them  Topics Impacted by Reliability Outline

12.  Planning systems for reliability  Analyzing systems for reliability  Designing systems for reliability  Implementing systems for reliability  Reliability engineering  Complexity  Simulation for testing reliability  Tools to simulate  What to test  How to determine the results  What to do after Challenges of Reliability

13.  Constraints  Redundancy and error recovery mechanisms are required  May require new features  Rigorously verified to ensure their correct implementation Challenges of Reliability

14. System TypeUnavailabilityReliability Class(9’s) (min/year)(%) Unmanaged52,56090%1 Managed5,25699%2 Well-Managed52699.9%3 Fault-tolerant5399.99%4 High-reliability599.999%5 Very-highly reliable0.599.9999%6 Ultra-highly reliable0.0599.99999%7 Reliability Classes

15.  A measure of trust of results produced by a system  Idea and concept is there and all there is to it is recognizing the situation and knowing that it has to be reliable.  Sufficient for use  User satisfaction  Meet standards of reliability System Reliability

16.  To achieve system reliability  Make sure the components of the system are constructed properly  Make sure that any failure or anything that is detected to be wrong be taken care of and fixed Solving System Reliability

17.  User plays a specific role and that is being a tester and judging the system and how reliable it is  Knowledge  Experience  Inexperienced user will not be able to determine reliability, the wrong in a hardware or system  Unreliable source  Challenging to find users that are going to determine reliability of a system User Reliability

18.  Developers have to keep in mind all types of users.  Novice Users:  Intermediate Users  Expert Users  Developer have to keep in mind user will sacrifice software efficiency when the price is right for them.  Sometimes the issue with having a good server is that today to have a cost efficient server sometimes means using systems of less quality and so the reliability suffers there  To solve: Not focusing on the cost.  To solve: Understanding point of view of the users and dedication of the developer. User Reliability

19.  System designer detects and corrects errors  User is open minded about the designers updates  For example in software:  Free of bugs and software correctly written.  Software bugs are frequently seen in both software and hardware.  When a software system get to where it is considered highly reliable then it has been examined to where the system is close to no errors in the software. Solving User Reliability

20.  What is Reliability?  Understanding differences between similar terms  Challenges of Reliability & How to Solve Them  Topics Impacted by Reliability Outline

21.  Large Impact  Measured by the frequency of failure, the time it takes to recover from a failure, and the network’s robustness in a catastrophe  Ensuring that each segment that the source sends arrives at its destination  Reliable protocols > delivery of data  Networking outages > still needs to be reliable Reliability in Networking

22.  Large Impact  Hard to face for OS designers & implementers  Wide variety of environments  Many different users relying on OS Reliability in Operating Systems

23.  Large Impact  Database Performance  requested information is always correctly and reliably stored and accessed Reliability in Databases

24.  Data Redundancy  Occurs in databases when a field is repeated in 2+ tables  Customer data attached to each product bought  Same data  Data redundancy can prevent data reliability Data Reliability

25. Questions?