Technical data

GL–2 Glossary
BBR See bad block replacement.
BIST See built-in self-test.
bit A single binary digit having a value of either 0 or 1. A bit is the smallest
unit of data a computer can process.
block Also called a sector. The smallest collection of consecutive bytes
addressable on a disk drive. In integrated storage elements, a block contains
512 bytes of data, error codes, flags, and the block’s address header.
bootstrapping A method used to bring a system or device into a defined state by means of
its own action. For example, a machine routine whose first few instructions
are enough to bring the rest of the routine into the computer from an input
device.
built-in self-test A diagnostic test performed by the array controller software on the
controller’s policy processor.
byte A binary character string made up of 8 bits operated on as a unit.
cache memory A portion of memory used to accelerate read and write operations.
CCITT Acronym for Consultive Committee International Telephone and Telegraph.
An international association that sets worldwide communication standards,
recently renamed International Telecommunications Union (ITU).
CDU Cable distribution unit. The power entry device for StorageWorks cabinets.
The CDU provides the connections necessary to distribute power to the
cabinet shelves and fans.
channel An interface which allows high speed transfer of large amounts of data.
Another term for a SCSI bus. See also SCSI.
chunk A block of data written by the host.
chunk size The number of data blocks, assigned by a system administrator, written to
the primary RAIDset or stripeset member before the remaining data blocks
are written to the next RAIDset or stripeset member.