Redundancy Check: A process used to ensure data integrity during storage or transmission by including additional data (such as parity bits or checksums). This added data allows the detection and sometimes correction of errors that may have occurred, enhancing the reliability of the data being delivered or retrieved.

Redundant Array of Independent Disks (RAID): A method of storing the same data in different places on multiple hard disks or solid-state drives to protect data in the case of a drive failure. Depending on the RAID level used, the benefits can include increased data reliability, improved system performance, or a combination of both. The RAID level chosen depends on the specific needs and resources of the organization.

Redundant Server: A backup server that duplicates the functions and data of a primary server. It is typically kept in standby mode and is designed to take over immediately in the event of a failure or downtime of the primary server, ensuring minimal or no disruption to the services. This level of redundancy is a vital part of maintaining high availability and disaster recovery capabilities in a network environment. It provides an additional layer of protection against data loss and service interruptions.

Redundant site: A mirror or duplicate of the primary site, housing the same data and capabilities. It serves as a backup or disaster recovery solution, enabling continued operations even when the main site experiences downtime, disruptions, or catastrophic events. Its role can be passive, waiting in the wings to take over when needed, or active, participating in load balancing to improve performance and reliability.

Refactoring: The process of restructuring or reorganizing existing code while maintaining its functionality. This practice is used to enhance code readability, reduce complexity, improve source code maintainability, and optimize system efficiency. It also facilitates easier troubleshooting and upgradeability, helping in identifying potential vulnerabilities and ensuring code adheres to the latest coding standards.

Reference monitor: A critical component of an access control system. It's responsible for regulating interactions between subjects (users or processes) and objects (resources) within a system. This is done by enforcing an access control policy that determines who or what can access certain resources and what operations they can perform. Its design must be tamper-proof and constantly active to ensure reliable enforcement of security policies.