Discretionary Access Control (DAC): A type of access control where the owner or administrator of the protected system, data, or resource sets the policies defining who or what is authorized to access the resource. In DAC models, access is based on the discretion of the owner. Users can be granted permission by an owner to read, write, or execute a file or program. This model is contrasted with mandatory access control (MAC), where access rights are regulated by a central authority based on multiple levels of security. DAC is known for its flexibility but can be less secure than MAC, as it allows users to control access to their own data, which they may not always do securely. DAC can lead to security risks if users are not careful in managing permissions.

Diskless Workstations: Computers that do not have internal storage. Instead, they rely on a network connection to a server from which they access operating systems, applications, and data. This approach can reduce the risk of local data theft or loss and makes system maintenance easier, as updates and changes can be performed centrally on the server.

Disk Mirroring: A technique used to protect data by duplicating it onto two or more disks. By writing the same data to a pair of storage devices, an exact copy, or mirror, is created. This strategy allows for data consistency and instant data recovery in case of a single disk failure, thereby ensuring high availability and resilience against data loss. While disk mirroring provides redundancy, it does not protect against data corruption since the same data is written to both disks.

Disk Striping: Splitting data across multiple physical disk drives can improve performance by allowing multiple drives to read and write data concurrently. Each piece of data is broken down into blocks, and each block is written to a separate disk. Disk striping does not provide data redundancy, meaning that if a single drive fails, all data in the stripe is lost.

Disk Striping With Parity: A technique that combines the performance benefits of disk striping with added redundancy for data protection. In addition to splitting data across multiple drives, it also writes parity information. Parity information is a kind of checksum that can be used to reconstruct data if a single drive fails. This approach provides a balance between performance and data safety.

Distance-Vector Routing Protocol: A network routing protocol that calculates the best path for data delivery by using metrics or distances. Each router communicates with its immediate neighbors to exchange information about network topology. Changes in the network are communicated across routers to prevent loops and ensure reliable data transmission.