Definition - What does Availability mean?
Availability, in the context of a computer system, refers to the ability of a user to access information or resources in a specified location and in the correct format.
Techopedia explains Availability
Availability is one of the five pillars of Information Assurance (IA). The other four are integrity, authentication, confidentiality and nonrepudiation.
When a system is regularly non-functioning, information availability is affected and significantly impacts users. In addition, when data is not secure and easily available, information security is affected, i.e., top secret security clearances. Another factor affecting availability is time. If a computer system cannot deliver information efficiently, then availability is compromised.
Data availability must be ensured by storage, which may be local or at an offsite facility. In the case of an offsite facility, an established business continuity plan should state the availability of this data when onsite data is not available. At all times, information must be available to those with clearance.