later, another variant, which was named intellisafe, was created by computer manufacturer compaq and disk drive manufacturers seagate, quantum, and conner. the disk drives would measure the disk’s "health parameters", and the values would be transferred to the operating system and user-space monitoring software. each disk drive vendor was free to decide which parameters were to be included for monitoring, and what their thresholds should be. the unification was at the protocol level with the host.