Host Bus Adapter - Definition and Overview

In general terms, a Host Bus Adapter (HBA) is any adapter that allows a computer bus to attach to another bus or channel. Today, the term is most often used to refer to a Fibre Channel interface card. However, the term has, in the past, referred to other bus interconnects, including SCSI and ESCON. Recently, the advent of iSCSI has brought about Ethernet HBAs, some including TCP Offload Engines.

Fibre Channel HBAs are available for all major open systems computers and busses, including PCI and SBUS. Each HBA has a unique World Wide Name (WWN), which is similar to an Ethernet MAC address in that it uses an OUI assigned by the IEEE. However, WWNs are longer (16 bytes).