Mainframe I/O channels

In the mainframe field, the agreement host adapter or host bus adapter were commonly not used. A agnate ambition is accomplished back 1960s with a altered technique: I/O channel, or artlessly channel, is a abstracted processor that can admission capital anamnesis independently, in alongside with CPU (like after DMA in claimed computer field), and that executes its own I/O-dedicated programs if acicular to such by the authoritative CPU.

Protocols acclimated by I/O channels to acquaint with borderline accessories cover ESCON and newer FICON.