Specifications

GL–2 Glossary
array controller
software
Abbreviated ACS. Software contained on a removable ROM program card that
provides the operating system for the array controller.
asynchronous Pertaining to events that are scheduled as the result of a signal asking for the
event; pertaining to that which is without any specified time relation.
See also
synchronous.
autospare A controller feature that automatically replaces a failed disk drive. To aid the
controller in automatically replacing failed disk drives, you can enable the
AUTOSPARE switch for the failedset causing physically replaced disk drives to be
automatically placed into the spareset. Also called “autonewspare.”
bad block A data block that contains a physical defect.
bad block
replacement
Abbreviated BBR. A replacement routine that substitutes defect-free disk blocks
for those found to have defects. This process takes place in the controller,
transparent to the host.
backplane The electronic printed circuit board into which you plug subsystem devices—for
example, the SBB or power supply.
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.