SCSI

Small Computer System Interface (SCSI, /ˈskʌzi/ SKUZ-ee) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices. The SCSI standard defines command sets for specific peripheral device types; the presence of "unknown" as one of these types means that in theory it can be used as an interface to almost any device, but the standard is highly pragmatic and addressed toward commercial requirements.

SCSI is an intelligent, peripheral, buffered, peer to peer interface. It hides the complexity of physical format. Every device attaches to the SCSI bus in a similar manner. Up to 8 or 16 devices can be attached to a single bus. There can be any number of hosts and peripheral devices but there should be at least one host. SCSI uses handshake signals between devices, SCSI-1, SCSI-2 have the option of parity error checking. Starting with SCSI-U160 (part of SCSI-3) all commands and data are error checked by a CRC32 checksum. The SCSI protocol defines communication from host to host, host to a peripheral device, peripheral device to a peripheral device. However most peripheral devices are exclusively SCSI targets, incapable of acting as SCSI initiators—unable to initiate SCSI transactions themselves. Therefore peripheral-to-peripheral communications are uncommon, but possible in most SCSI applications. The Symbios Logic 53C810 chip is an example of a PCI host interface that can act as a SCSI target.

Read more about SCSI:  History, Interfaces, SCSI Command Protocol, Device Identification, Device Type, SCSI Enclosure Services

Other articles related to "scsi":

SCSI / ATA Translation
... SCSI / ATA Translation (SAT) is a standard defining how to communicate with ATA devices through a SCSI application layer ... The standard attempts to be consistent with the SCSI architectural model, the SCSI Primary Commands, and the SCSI Block Commands standards ... The standard allows for translation of common SCSI Block Commands such as SCSI Read Commands SCSI Write Commands The standard also provides the ability to control exactly what ATA operations are ...
SAF-TE
... In computer storage, a SCSI Accessed Fault-Tolerant Enclosure is an industry standard to interface an enclosure to a (parallel) SCSI subystem to gain ... A SAF-TE device is represented as a SCSI processor device that is polled every couple of seconds by e.g ... For SAS or Fibre Channel systems, SAF-TE is replaced by the more standardized SCSI Enclosure Services ...
SES-2 Enclosure Management
... The introduction of Serial Attached SCSI (SAS) as the most recent evolution of SCSI required to re-define the related standard for enclosure management ... SES-2, or SCSI Enclosure Management 2 first revision was introduced in 2002 and is now at revision 20 ... SES-2 SCSI Enclosure Services (SES) permit the management and sense the state of power supplies, cooling devices, LED displays, indicators, individual drives, and other non-S ...
SCSI Pass-Through Direct - See Also
... SCSI Advanced SCSI Programming Interface (ASPI) SCSI Pass Through Interface (SPTI) ...
SCSI Enclosure Services
... In larger SCSI servers, the disk-drive devices are housed in an intelligent enclosure that supports SCSI Enclosure Services (SES) ... The initiator can communicate with the enclosure using a specialized set of SCSI commands to access power, cooling, and other non-data characteristics ...