A host computer.

An I/O adapter.

A disk array whose Array Management Function executes in host computer(s) rather than in a disk system. The member disks of a host-based array may be part of different disk systems.

A host I/O bus.

An I/O adapter that connects a host I/O bus to the host’s memory system.

Any computer system to which disks are attached and accessible for data storage and I/O. Mainframes, servers, workstations and personal computers, as well as multiprocessors and computer complexes such as clusters and sysplexes are all referred to as host computers in RAID Advisory Board publications.

An I/O bus used to connect a host computer to storage systems or storage devices.

A disk being used as a hot standby component.

The substitution of a replacement unit in a storage system for a defective unit, where the substitution can be performed while the system is performing its normal function. Hot swaps are manual operations typically performed by humans.