Modern disks

Modern disks are more like the Winchester disks used as PC hard drives and are supplied in multiple within a cabinet containing both its own processor and memory.

This type of disk is not recognised by the mainframe Operating Systems, so the inbuilt processor needs to act as an emulator for the CKD devices the Operating System understands.

This type of disk sub-system offers all the capabilities of a Redundant Array of Inexpensive Disks (RAID).

See more on cache.