Scalar i500 User’s Guide 233Glossary1U, 2U, 3U, etc.Racks manufactured for mounting computer hardware often define vertical space as "units." Thecomponents that are mounted in the racks are defined by how many units of rack space they require. Forexample, the height of a unit in a rack is 1.75". If a component is 5.25" in thickness, the component is saidto be a 3U component.Arbitrated loopA Fibre Channel configuration that attaches multiple communicating ports in a loop. Two or more ports caninterconnect, but only two ports can communicate simultaneously.ArbitrationThe submission of a request to gain access to an arbitrated loop by a device, so that it can transmit data inthe loop.AvailabilityA RAS attribute that refers to the accessibility of a system resource in a timely manner; for example, themeasurement of a system’s uptime.BarcodeA printed array of varied rectangular bars and spaces that can be scanned and read for object identification.BusA transmission channel through which electrical signals are carried from one device to another device.CAN (Controller Area Network)A serial bus network of microcontrollers that connects devices, sensors and actuators in a system or sub-system for real-time control applications. There is no addressing scheme used in controller area networks,as in the sense of conventional addressing in networks (such as Ethernet). Rather, messages are broadcastto all the nodes in the network using an identifier unique to the network.CartridgeA container that is a protective housing for storage media, such as cartridges for tapes or optical disks.Channel zoningA method of subdividing a storage area network into disjoint zones on a per-channel basis in order toenhance security and qualify access.Cleaning tape / cleaning cartridgeA tape used to clean recording heads and reading heads on a tape drive.Cleaning slotThe physical home where a cleaning tape or cartridge resides.CLI (Command Line Interface)A method of interfacing with a file system in which the user types commands, using a specific commandsyntax, from a command line.
