Editing Disk array controller (section)

== Front-end and back-end side ==
A disk array controller provides front-end interfaces and back-end interfaces.
* The back-end interface communicates with the controlled disks. Hence, its protocol is usually [[Advanced Technology Attachment|ATA]] (a.k.a. PATA), [[Serial ATA|SATA]], [[SCSI]], [[Fibre Channel|FC]] or [[Serial Attached SCSI|SAS]].
* The front-end interface communicates with a computer's [[host adapter]] (HBA, Host Bus Adapter) and uses:
** one of ATA, SATA, SCSI, FC; these are popular protocols used by disks, so by using one of them a controller may transparently [[emulator|emulate]] a disk for a computer.
** somewhat less popular dedicated protocols for specific solutions: [[FICON]]/[[ESCON]], [[iSCSI]], [[HyperSCSI]], [[ATA over Ethernet]] or [[InfiniBand]].

A single controller ''may'' use different protocols for back-end and for front-end communication. Many enterprise controllers use FC on front-end and SATA on back-end.