Glossary, Continued

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 disk 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.

MB

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

 

1,000 KB (kilobytes).

Multi-threadedHaving 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.

Cont’d

Glossary125