Search results
Results from the WOW.Com Content Network
Availability is the probability that a system will work as required when required during the period of a mission. The mission could be the 18-hour span of an aircraft ...
In reliability engineering, the term availability has the following meanings: . The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, i.e. a random, time.
Availability is typically given as a percentage of the time a system is expected to be available, e.g., 99.999 percent ("five nines"). Serviceability or maintainability is the simplicity and speed with which a system can be repaired or maintained; if the time to repair a failed system increases, then availability will decrease. Serviceability ...
However, given the true definition of availability, the system will be approximately 99.9% available, or three nines (8751 hours of available time out of 8760 hours per non-leap year). Also, systems experiencing performance problems are often deemed partially or entirely unavailable by users, even when the systems are continuing to function.
Operational availability is used to evaluate the following performance characteristic. For a system that is expected to be available constantly, the below operational availability figures translate to the system being unavailable for approximately the following lengths of time (when all outages during a year are added together):
The terms high availability, continuous operation, and continuous availability are generally used to express how available a system is. [3] [4] The following is a definition of each of these terms. High availability refers to the ability to avoid unplanned outages by eliminating single points of failure. This is a measure of the reliability of ...
Minimum required availability of complex system is a key factor of many distributed and repairable systems like ATM network or Airliner. In Availability-based Contracts, [2] instead of parts, the supplier is paid for a guaranteed level of services, performance, and system capability, similar to availability-based tariffs for electric power. [3]
High availability software can help engineers create complex system architectures that are designed to minimize the scope of failures and to handle specific failure modes. A “normal” failure is defined as one which can be handled by the software architecture's, while a “catastrophic” failure is defined as one which is not handled.