In computer hardware, a host controller, host adapter, or host bus adapter (HBA) connects a host arrangement (the computer) to added arrangement and accumulator devices. The agreement are primarily acclimated to accredit to accessories for abutting SCSI, Fibre Channel and eSATA devices, but accessories for abutting to IDE, Ethernet, FireWire, USB and added systems may aswell be alleged host adapters. Recently, the appearance of iSCSI and Fibre Channel over Ethernet has brought about Ethernet HBAs, which are altered from Ethernet NICs in that they cover TCP Offload Engines. There are aswell converged HBAs that abutment both Ethernet and Fibre Channel alleged Converged Arrangement Adapters (CNAs).
Thursday, 29 March 2012
SCSI
A SCSI host adapter connects host arrangement to cossack from a SCSI device, but aswell facilitates agreement of the host adapter. Typically a accessory driver, affiliated to the operating system, controls the host adapter itself.
In a archetypal alongside SCSI subsystem, anniversary accessory has assigned to it a different after ID. As a rule, the host adapter appears as SCSI ID 7, which gives it the accomplished antecedence on the SCSI bus (priority descends as the SCSI ID descends; on a 16-bit or "wide" bus, ID 8 has the everyman priority, a affection that maintains affinity with the antecedence arrangement of the 8-bit or "narrow" bus).
The host adapter usually assumes the role of SCSI initiator, in that it issues commands to added SCSI devices.
A computer can accommodate added than one host adapter, which can abundantly access the amount of SCSI accessories available.
Major SCSI adapter manufacturers are HP, ATTO Technology, Promise Technology, Adaptec, and LSI Logic. LSI, Adaptec, and ATTO currently action PCIe SCSI adapters which fit in new Apple Mac, on Intel PCs, and humble motherboards from companies like HP (which now abridgement SCSI abutment due to the admittance of SAS and/or SATA connectivity)....
In a archetypal alongside SCSI subsystem, anniversary accessory has assigned to it a different after ID. As a rule, the host adapter appears as SCSI ID 7, which gives it the accomplished antecedence on the SCSI bus (priority descends as the SCSI ID descends; on a 16-bit or "wide" bus, ID 8 has the everyman priority, a affection that maintains affinity with the antecedence arrangement of the 8-bit or "narrow" bus).
The host adapter usually assumes the role of SCSI initiator, in that it issues commands to added SCSI devices.
A computer can accommodate added than one host adapter, which can abundantly access the amount of SCSI accessories available.
Major SCSI adapter manufacturers are HP, ATTO Technology, Promise Technology, Adaptec, and LSI Logic. LSI, Adaptec, and ATTO currently action PCIe SCSI adapters which fit in new Apple Mac, on Intel PCs, and humble motherboards from companies like HP (which now abridgement SCSI abutment due to the admittance of SAS and/or SATA connectivity)....
Fibre Channel
Today, the appellation host bus adapter (HBA) is a lot of generally acclimated to accredit to a Fibre Channel interface card. Fibre Channel HBAs are accessible for all above accessible systems, computer architectures, and buses, including PCI and SBus (obsolete today). Anniversary HBA has a altered World Wide Name (WWN), which is agnate to an Ethernet MAC abode in that it uses an OUI assigned by the IEEE. However, WWNs are best (8 bytes). There are two types of WWNs on a HBA; a bulge WWN (WWNN), which is aggregate by all ports on a host bus adapter, and a anchorage WWN (WWPN), which is altered to anniversary port. There are HBA models of altered speeds: 1Gbit/s, 2Gbit/s, 4Gbit/s, 8Gbit/s, 10Gbit/s and 20Gbit/s.
The above Fibre Channel HBA manufacturers are QLogic and Emulex. As of mid-2009, these vendors aggregate about 90% of the market.12 Other manufacturers cover Agilent, ATTO, Brocade, and LSI.
HBA is aswell accepted to be interpreted as High Bandwidth Adapter in cases of Fibre Channel controllers.
The above Fibre Channel HBA manufacturers are QLogic and Emulex. As of mid-2009, these vendors aggregate about 90% of the market.12 Other manufacturers cover Agilent, ATTO, Brocade, and LSI.
HBA is aswell accepted to be interpreted as High Bandwidth Adapter in cases of Fibre Channel controllers.
InfiniBand
The appellation host approach adapter (HCA) is usually acclimated to call InfiniBand interface cards
.
ATA
ATA host adapters are chip into motherboards of a lot of avant-garde PCs. They are generally break alleged deejay controllers. The actual appellation for the basic that allows a computer to allocution to a borderline bus is host adaptercitation needed. A able deejay ambassador alone allows a deejay to allocution to the aforementioned bus.
.
ATA
ATA host adapters are chip into motherboards of a lot of avant-garde PCs. They are generally break alleged deejay controllers. The actual appellation for the basic that allows a computer to allocution to a borderline bus is host adaptercitation needed. A able deejay ambassador alone allows a deejay to allocution to the aforementioned bus.
SAS and SATA
SAS or serial-attached SCSI is the accepted connectivity to alter the antecedent bearing parallel-attached SCSI (PAS) devices. Ultra320 was the accomplished akin of alongside SCSI available, but SAS has back replaced it as the highest-performing SCSI technology.
SATA is a agnate technology from the aspect of affiliation options. HBAs can be created application a individual adapter to affix both SAS and SATA devices.
Major SAS/SATA adapter manufacturers are Promise Technologies, Adaptec, HP, QLogic, Areca, LSI and ATTO Technology.
SATA is a agnate technology from the aspect of affiliation options. HBAs can be created application a individual adapter to affix both SAS and SATA devices.
Major SAS/SATA adapter manufacturers are Promise Technologies, Adaptec, HP, QLogic, Areca, LSI and ATTO Technology.
eSATA
External Serial ATA deejay enclosures and drives are more common[citation needed] in the customer accretion market, but not all SATA-compatible motherboards and deejay controllers cover alien SATA ports. As such, adapters to affix alien SATA accessories to ports on an centralized SATA bus are frequently available.
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.
Protocols acclimated by I/O channels to acquaint with borderline accessories cover ESCON and newer FICON.
Subscribe to:
Posts (Atom)