Reliability

Reliability is the basic ability of a software system to maintain the functional characteristics of a software system in the face of application or system errors, in the event of accidental or erroneous use.

Software reliability does not equal hardware reliability. The differences include the following:

• Complexity: Software is more complex than hardware, and most failures come from software failures.
• Physical degradation: Hardware failures are mainly caused by physical degradation, and software does not have physical degradation.
• Uniqueness: Software is unique, every COPY version is the same, and two hardwares cannot be exactly the same.
• Version update cycle: hardware is slower, software is faster.

Availability

Availability is the percentage of time a system is up and running.

There is little difference between usability and reliability. In architecture design, usability is often mentioned; in paper writing, reliability is often mentioned.

Reliability Indicators

• Mean Time To Failure&