IBM 86655RY Hardware Maintenance Manual - Page 221

DDD Defunct disk drive. defunct Unrecoverable; failed; not responding. DHS Defunct hot-spare. A hot-spare or standby hot-spare drive enters the defunct hot-spare (DHS) state if it fails to respond to the adapter commands. Once a Defunct (DHS) drive is replaced, its state changes from DHS to HSP. Only the IBM ServeRAID adapter has the DHS state. disk array A grouping of hard disks that can be logically considered one drive. A grouping of hard disks over which a data file is spread. electronically erasable programmable read-only memory (EEPROM) A PROM that can be erased by a special process and reused. EMP Empty. No device is present in the SID or the adapter cannot communicate with the drive. This state is represented with dashes (- - -) on the IBM ServeRAID configuration screen, or a blank space on the Administration and Monitor screen. Only the IBM ServeRAID adapter has this state. GB Gigabyte; equal to approximately one billion bytes. hard disk drive A stand-alone disk drive that reads and writes data on rigid disks. hot-spare drive A hard disk drive that is installed in a computer and configured by the system for use in the event of a drive failure. HSP Hot-Spare. In the ServeRAID family of controllers, a hot-spare (HSP) drive is a drive designated to be a replacement for the first Defunct (DDD) drive that occurs. The state of the drive appears as HSP. When a Defunct (DDD) drive occurs and a HSP is defined, the hot-spare drive takes over for the drive that appears as Defunct (DDD). The HSP drive is rebuilt to be identical to the Defunct (DDD) drive. During the rebuilding of the HSP drive, this drive changes to the Rebuild (RBL) state. The RBL state will turn to ONL once the drive is completely rebuilt and fully operating for the Defunct (DDD) drive. initialize To set counters, switches, addresses, or contents of storage to zero or other starting values at the beginning of, or at prescribed points in, the operating of a computer routine. To prepare for use; for example, to initialize a hard disk or diskette. interleave To arrange parts of one sequence of things or events so that they alternate with parts of one or more other sequences of the same nature and so that each sequence retains its identity. interleave depth The granularity at which data from one file is stored on one drive of the array before subsequent data is stored on the next drive in the array. interleaving The simultaneous accessing of two or more bytes or streams of data from distinct storage units. ISPR Interrupt Status Port register. KB Kilobyte; equal to approximately 1000 bytes. LDM Logical drive migration. logical drive Part of an array. Installing and configuring ServeRAID controllers 211