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Enclosure Services Interface
The Enclosure Services Interface (ESI) is a computer protocol used in SCSI enclosures. This is part of a chain of connections that allows a host computer to communicate with the enclosure to access its power, cooling, and other non-data characteristics. This overall approach is called SCSI attached enclosure services: The host computer communicates with the disks in the enclosure via a Serial SCSI interface (which may be either FC-AL or SAS). One of the disk devices located in the enclosure is set up to allow SCSI Enclosure Services (SES) communication through a LUN. The disk-drive then communicates with the SES processor in the enclosure via ESI. The data sent over the ESI interface is simply the contents of a SCSI command and the response to that command. In fault-tolerant enclosures, more than one disk-drive slot has ESI enabled to allow SES communications to continue even after the failure of any of the dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI
Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interfaces. 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. The initial Parallel SCSI was most commonly used for hard disk drives 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 ancestral SCSI standard, X3.131-1986, generally referred to as SCSI-1, was published by the X3T9 technical committee of the American National Standards Institute (ANSI) in 1986. SCSI-2 was published in August 1990 as X3.T9.2/86-109 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI Attached Enclosure Services
SCSI Enclosure Services (SES) is a protocol for more modern SCSI enclosure products. An initiator can communicate with the enclosure using a specialized set of SCSI commands to access power, cooling, and other non-data characteristics. SES devices There are two major classes of SES devices: * Attached enclosure services devices allow SES communication through a logical unit within one SCSI disk drive located in the enclosure. The disk-drive then communicates with the enclosure by some other method, the only commonly used one being Enclosure Services Interface (ESI). In fault-tolerant enclosures, more than one disk-drive slot has ESI enabled to allow SES communications to continue even after the failure of any of the disk-drives. The definition of the ESI protocols is owned by an ANSI committee and defined in their specifications ANSI SFF-8067 and SFF-8045. * Standalone enclosure services enclosures have a separate SES processor which occupies its own address on the SCSI bus. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbitrated Loop
The arbitrated loop, also known as FC-AL, is a Fibre Channel topology in which devices are connected in a one-way loop fashion in a ring topology. Historically it was a lower-cost alternative to a fabric topology. It allowed connection of many servers and computer storage devices without using then very costly Fibre Channel switches. The cost of the switches dropped considerably, so by 2007, FC-AL had become rare in server-to-storage communication. It is however still common within storage systems. * It is a serial architecture that can be used as the transport layer in a SCSI network, with up to 127 devices. The loop may connect into a fibre channel fabric via one of its ports. * The bandwidth on the loop is shared among all ports. * Only two ports may communicate at a time on the loop. One port wins arbitration and may open one other port in either half or full duplex mode. * A loop with two ports is valid and has the same physical topology as point-to-point, but still ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI Enclosure Services
SCSI Enclosure Services (SES) is a protocol for more modern SCSI enclosure products. An initiator can communicate with the enclosure using a specialized set of SCSI commands to access power, cooling, and other non-data characteristics. SES devices There are two major classes of SES devices: * Attached enclosure services devices allow SES communication through a logical unit within one SCSI disk drive located in the enclosure. The disk-drive then communicates with the enclosure by some other method, the only commonly used one being Enclosure Services Interface (ESI). In fault-tolerant enclosures, more than one disk-drive slot has ESI enabled to allow SES communications to continue even after the failure of any of the disk-drives. The definition of the ESI protocols is owned by an ANSI committee and defined in their specifications ANSI SFF-8067 and SFF-8045. * Standalone enclosure services enclosures have a separate SES processor which occupies its own address on the SCSI bus. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Unit Number
In computer storage, a logical unit number, or LUN, is a number used to identify a logical unit, which is a device addressed by the SCSI protocol or by Storage Area Network protocols that encapsulate SCSI, such as Fibre Channel or iSCSI. A LUN may be used with any device which supports read/write operations, such as a tape drive, but is most often used to refer to a logical disk as created on a SAN. Though not technically correct, the term "LUN" is often also used to refer to the logical disk itself. Examples To provide a practical example, a typical multi-disk drive has multiple physical SCSI ports, each with one SCSI target address assigned. An administrator may format the disk array as a RAID and then partition this RAID into several separate storage-volumes. To represent each volume, a SCSI target is configured to provide a logical unit. Each SCSI target may provide multiple logical units and thus represent multiple volumes, but this does ''not'' mean that those volumes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI Command
In SCSI computer storage, computers and storage devices use a client-server model of communication. The computer is a client which requests the storage device to perform a service, e.g., to read or write data. The SCSI command architecture was originally defined for parallel SCSI buses but has been carried forward with minimal change for use with Fibre Channel, iSCSI, Serial Attached SCSI, and other transport layers. In the SCSI protocol, the initiator An initiator can refer to: * A person who instigates something. * Modulated neutron initiator, a neutron source used in some nuclear weapons ** Initiator, an Explosive booster ** Initiator, the first Nuclear chain reaction * Pyrotechnic initiato ... sends a SCSI command information unit to the target device. Data information units may then be transferred between the computer and device. Finally, the device sends a response information unit to the computer. SCSI commands are sent in a command descriptor block (CDB), which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibre Channel Network Protocols
Communication between devices in a fibre channel network uses different elements of Fibre Channel standards. Transmission words and ordered sets All Fibre Channel communication is done in units of four 10-bit codes. This group of 4 codes is called a transmission word. An ordered set is a transmission word that includes some combination of control (K) codes and data (D) Fibre Channel 8b/10b encoding, codes. AL_PAs Each device has an Arbitrated_loop, Arbitrated Loop Physical Address (AL_PA). These addresses are defined by an 8-bit field but must have neutral disparity as defined in the Fibre Channel 8b/10b encoding, 8b/10b coding scheme. That reduces the number of possible values from 256 to 134. The 134 possible values have been divided between the fabric, FC_AL Computer_port_(hardware), ports, and other special purposes as follows: Meta-data In addition to the transfer of data, it is necessary for Fibre Channel communication to include some metadata. This allows for the sett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI Send Diagnostic Command
Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interfaces. 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. The initial Parallel SCSI was most commonly used for hard disk drives 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 ancestral SCSI standard, X3.131-1986, generally referred to as SCSI-1, was published by the X3T9 technical committee of the American National Standards Institute (ANSI) in 1986. SCSI-2 was published in August 1990 as X3.T9.2/86-109, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI Diagnostic Pages
SCSI target devices provide a number of SCSI diagnostic pages. These can be used by a Send Diagnostic command to tell a target device to run a specialised self-test. The Receive Diagnostic Results command is used where the results from the self-test operation are non-trivial. Most of the common SCSI devices such as disk-drives support only one or two diagnostic pages. SES SES, S.E.S., Ses and similar variants can refere to: Business and economics * Socioeconomic status * Scottish Economic Society, a learned society in Scotland * SES, callsign of the TV station SES/RTS (Mount Gambier, South Australia) * SES S.A., ... devices can support many diagnostic pages. List of SCSI diagnostic pages SCSI uses a one byte addressing scheme for diagnostic pages, allowing for a total 256 possible pages. There is a standard map of diagnostic page addresses shown below. Note that any given SCSI device type will only support a subset of these diagnostic pages. Some diagnostic pages ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCSI Standalone Enclosure Services
SCSI standalone enclosure services is a computer protocol used mainly with disk storage enclosures. It allows a host computer to communicate with the enclosure to access its power, cooling, and other non-data characteristics. The host computer communicates with one or more SCSI Enclosure Services (SES) controllers in the enclosure via a SCSI interface which may be Parallel SCSI, FC-AL, SAS, or SSA. Each SES controller has a SCSI identity (address) and so can accept direct SCSI commands. Implemented commands The following SCSI commands are implemented by standalone enclosure services devices: Note 1: The initiator An initiator can refer to: * A person who instigates something. * Modulated neutron initiator, a neutron source used in some nuclear weapons ** Initiator, an Explosive booster ** Initiator, the first Nuclear chain reaction * Pyrotechnic initiator, ... needs to send a SCSI inquiry to interrogate the SCCS bit which says whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Storage Architecture
Serial Storage Architecture (SSA) was a serial transport protocol used to attach disk drives to server computers. History SSA was invented by Ian Judd of IBM in 1990. IBM produced a number of successful products based upon this standard before it was overtaken by the more widely adopted Fibre Channel protocol. SSA was promoted as an open standard by the SSA Industry Association, unlike its predecessor the first generation Serial Disk Subsystem. A number of vendors including IBM, Pathlight Technology and Vicom Systems produced products based on SSA. It was also adopted as an American National Standards Institute (ANSI) X3T10.1 standard. SSA devices are logically SCSI devices and conform to all of the SCSI command protocols. SSA provides data protection for critical applications by helping to ensure that a single cable failure will not prevent access to data. All the components in a typical SSA subsystem are connected by bi-directional cabling. Data sent from the adaptor can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
