Introduction
Reliability: accuracy of data or the correspondence of data with the real world. Data may be unreliable if: entered incorrectly; outdated. Reliability determines our confidence in their value.
EX: Medical record that dissociates from the patient it refers to becomes unreliable.
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Reliable Hardware:
EX: Microsoft updates because it is exploiting the vulnerability of the software. This means that it is vulnerable for attacks from outside
Software Reliability is the probability of failure-free software operation for a specified period of time in a specified environment. Software Reliability is also an important factor affecting system reliability. It differs from hardware reliability in that it reflects the design perfection, rather than manufacturing perfection. The high complexity of software is the major contributing factor of Software Reliability problems. Software Reliability is not a function of time - although researchers have come up with models relating the two. The modeling technique for Software Reliability is reaching its prosperity, but before using the technique, we must carefully select the appropriate model that can best suit our case. Measurement in software is still in its infancy. No good quantitative methods have been developed to represent Software Reliability without excessive limitations. Various approaches can be used to improve the reliability of software, however, it is hard to balance development time and budget with software reliability.
Integrity: safeguarding the accuracy and completeness of stored data. Data lacks integrity when: changed accidentally or tampered with.
Examples: information is duplicated in relational database and only one copy is updated; data maliciously altered.
Data integrity
Refers to the validity of data
Data integrity can be compromised in a number of ways:
• Human errors when data is entered
• Errors that occur when data is transmitted from one computer to another
• Software bugs or viruses
• Hardware malfunctions, such as disk crashes
• Natural disasters, such as fires and floods
There are many ways to minimize these threats to data integrity. These include:
• Backing up data regularly
• Controlling access to data via security mechanisms
• Designing user interfaces that prevent the input of invalid data
• Using error detection and correction software when transmitting data