HP Array Controller HSG V8.7 Software - Manual (Page 531)

Glossary G–5
differential SCSI bus A bus in which a signal’s level is determined by the potential difference
between two wires. A differential bus is more robust and less subject to
electrical noise than is a single-ended bus.
DIMM Dual inline Memory Module.
dirty data The write-back cached data that has not been written to storage media,
even though the host operation processing the data has completed.
DMA Direct Memory Access.
DOC DWZZA-On-a-Chip. An NCR53C120 SCSI bus extender chip used to
connect a SCSI bus in an expansion cabinet to the corresponding SCSI
bus in another cabinet.
driver A hardware device or a program that controls or regulates another
device. For example, a device driver is a driver developed for a specific
device that allows a computer to operate with the device, such as a
printer or a disk drive.
dual-redundant
configuration A controller configuration consisting of two active controllers operating
as a single controller. If one controller fails, the other controller
assumes control of the failing controller’s devices.
dual-simplex A communications protocol that allows simultaneous transmission in
both directions in a link, usually with no flow control.
DUART Dual universal asynchronous receiver and transmitter. An integrated
circuit containing two serial, asynchronous transceiver circuits.
ECB External cache battery. The unit that supplies backup power to the
cache module in the event the primary power source fails or is
interrupted.
ECC Error checking and correction.
EDC Error detection code.
EIA The abbreviation for Electronic Industries Association. EIA is a
standards organization specializing in the electrical and functional
characteristics of interface equipment. Same as Electronic Industries
Association.