Initialization—The process of writing zeros to the data fields of a logical drive and generating the corresponding parity to bring the logical drive to a ready state. Initializing erases previous data and generates parity so that the logical drive will pass a consistency check. Arrays can work without initializing, but they can fail a consistency check because the parity fields have not been generated.

Logical Disk—A set of contiguous chunks on a physical disk. Logical disks are used in array implementations as constituents of logical volumes or partitions. Logical disks are normally transparent to the host environment, except when the array containing them is being configured.

Logical Drive—A virtual drive within an array that can consist of more than one physical drive. Logical drives divide the contiguous storage space of an array of hard drives or a spanned group of arrays of drives. The storage space in a logical drive is spread across all the physical drives in the array or spanned arrays. Configure at least one logical drive for each array.

Mapping—The conversion between multiple data addressing schemes, especially conversions between member disk block addresses and block addresses of the virtual disks presented to the operating environment by Array Management Software.

Megabyte (MB)— An abbreviation for 1,000,000 (10 to the sixth power) bytes. It is the same as 1,000 KB (kilobytes).

Multi-threaded—Having multiple concurrent or pseudo-concurrent execution sequences. Used to describe processes in computer systems. Multi-threaded processes allow throughput-intensive applications to efficiently use a disk array to increase I/O performance.

Operating Environment—The operating environment includes the host computer where the array is attached, any I/O buses and adapters, the host operating system, and any additional software required to operate the array. For host-based arrays, the operating environment includes I/O driver software for the member disks, but does not include Array Management Software, which is regarded as part of the array itself.

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