Editing Host adapter (section)

==Mainframe channel I/O==
{{Main|Channel I/O}}
In the [[mainframe computer|mainframe]] field, the terms ''host adapter'' or ''host bus adapter'' were traditionally not used.
A similar goal was achieved since the 1960s with channel I/O, a separate processor that can access [[main memory]] independently, in parallel with CPU (like later [[Direct memory access|DMA]] in [[personal computer]] field), and that executes its own I/O-dedicated [[computer program|program]]s when pointed to such by the controlling CPU.{{cn|reason=Broad statement which is hard to verify –  is there a specific example of this?|date=July 2019}}

Protocols used by channel I/O to communicate with [[peripheral device]]s include [[ESCON]] and newer [[FICON]].