Host adapter

A host bus adapter occurs both as an optional extension ( plug-in card ) as well as in soldered onto the motherboard form.

Host bus adapters are in common parlance often referred to by the English word " Controller" (eg " IDE controller "). But this is - also in English - no correct term, because the attached devices nowadays have all their own controller and the host bus adapter does not fulfill this task. The term " controller " comes from a time when hard drives still did not own controller and the hard disk controller actually put a plug-in cards into the motherboards of computers ( see, eg, ST506, ATA / ATAPI: History ). Today, hard disk controllers are located on the underside of disks on their board. The latter also contains the interface to the bus system.

The term is used primarily in connection with the bus systems, SCSI, ATA ( IDE), SATA and Fibre Channel. In principle, however, is also a network card HBA.

Another type of HBA, the TCP Offload Engine ( TOE) represents a TOE is comparable to an active Ethernet network card, as it is often used in servers. The purpose of this map is to perform computationally intensive operations on the TOE and thus to relieve the CPU of the server.

An interesting development of the HBA associated with Fibre Channel over Ethernet is also the Converged Network Adapter (CNA ), with which terminals are directly connected to the FCoE fabric. Such an adapter provides both Fibre Channel host bus adapter and classic network interface card functions on a hardware.

Among the most famous manufacturers of HBA or TOE cards include Adaptec, QLogic, JNI, LSI ( Engenio ), Alacritech and Emulex.