host adapter
A host controller ( host controller ), host adapter ( host adapter ) or host bus adapter ( host bus adapter , HBA ) is a computer hardware that connects a computer as the host system to other network or storage devices . The term primarily refers to expansion cards that connect to SCSI , SAS , or Fiber Channel devices . However, expansion cards that connect to IDE , SATA , Ethernet , IEEE 1394 , USB , or other buses may also be called host adapters.
Fiber Channel host bus adapter (a 64 -bit PCI-X board)
SCSI host bus adapter (a 16 -bit ISA board)
The term network interface controller (NIC) more commonly refers to a device that connects to a computer network .
SCSI
In a typical parallel SCSI subsystem, each device is assigned a unique numerical ID. In general, host adapters appear as SCSI ID 7, which gives it the highest priority on the SCSI bus (priority decreases with SCSI ID; on 16-bit or "wide" buses, ID 8 has the lowest priority , the design is guaranteed to be compatible with priority schemes for 8-bit or "narrow" buses).
A host adapter typically assumes the role of a SCSI initiator because it issues commands to other SCSI devices.
Computers can contain multiple host adapters, which can increase the number of SCSI devices available.
Major SCSI adapter manufacturers include Hewlett-Packard , ATTO Technology, Promise Technology, Adaptec, and LSI Corporation .
fiber channel
Each Fiber Channel HBA has a unique World Wide Name (WWN), which is similar to the IEEE- assigned Organizationally Unique Identifier (OUI)-Ethernet MAC address . However, the WWN is longer (8 bytes). There are two types of WWNs on an HBA: node WWNs (WWNNs) are shared by all ports on the host bus adapter, and port WWNs (WWPNs) are unique to each port.
The major Fiber Channel HBA manufacturers are QLogic and Emulex. As of 2009, these suppliers shared approximately 90% market share. [1] [2] Other manufacturers include Agilent Technologies , ATTO, Brocade, and LSI Corporation .
InfiniBand
Host Channel Adapter (HCA) is often used to describe an InfiniBand interface card.
ATA
ATA host adapters are integrated into most modern PCs . They are often called disk controllers.
SAS and SATA
SAS (Serial SCSI) is the current connection method that replaces Parallel SCSI (PAS, obsolete) devices. Ultra320 is the most advanced parallel SCSI available, but SAS has replaced it as the highest performance SCSI technology. SAS/SCSI generally requires the operating system to have built-in/installed drivers for the HBA.
SATA is ATA using serial technology, which has replaced the IDE interface invented by Western Digital. SATA is mainly used in low-end applications such as personal computers. The SAS port of the SAS HBA can be connected to a SATA device, whereas the SATA port of the SATA controller cannot be connected to a SAS device. The SATA controller can use the AHCI operation mode or the IDE operation mode (but starting from the Intel 9 series PCH , the SATA controller of Intel's PC chipset no longer supports the IDE operation mode). AHCI is the native operation mode of SATA, and Windows starting from Windows Vista has a built-in general Microsoft AHCI driver. IDE mode is to simulate the SATA hard disk as an IDE device to support Windows XP and other operating systems that do not support AHCI, which will cause a certain degree of performance loss.
Major SAS adapter manufacturers are: Promise Technologies, Adaptec, HP , QLogic, Areca, LSI /AVAGO, and ATTO Technology. Most chipsets have built-in SATA functionality.
host I/O channel
In mainframe computers , the terms host adapter or host bus adapter are not traditionally used. A different technology has been used since the 1960s to accomplish a similar goal: an I/O channel, or simply a "channel", which is a separate processor that can independently access main memory in parallel with the CPU, similar to DMA in a personal computer , and they execute their own I/O-specific computer programs when directed by the CPU .
Protocols used by I/O channels for communicating with external devices include ESCON and the newcomer FICON.
see
- network card
- fiber channel
- converged network adapter
- host controller interface for USB and FireWire host adapters,