Dell PowerEdge RAID Controller 5i - Manual (Page 101)

Glossary
99
Glossary
A
Adapter
An adapter enables the computer system to access
peripheral devices by converting the protocol of one
bus or interface to another. An adapter may also
provide specialized function. For example, a RAID
controller is a type of adapter that provides RAID
functions. Adapters may reside on the system board or
be an add-in card. Other examples of adapters include
network and SCSI adapters.
Adaptive Read Ahead
Adaptive read ahead is a read policy that specifies that
the controller begins using read-ahead caching if the
two most recent disk accesses occurred in sequential
sectors. If all read requests are random, the algorithm
reverts to Non read ahead; however, all requests are
still evaluated for possible sequential operation.
B
Background Initialization
Background initialization is the automatic check for
media errors on physical disks. It ensures that striped
data segments are the same on all physical disks in a
virtual disk. The difference between a background
initialization and a consistency check is that a
background initialization is automatic for new virtual
disks. The operation starts within five minutes after
you create the disk.
Baseport
Base register of the memory address range provided by
the host.
Battery Backup Unit (BBU)
The battery backup unit protects the integrity of the
cached data on the controller by providing backup
power if there is a complete AC power failure or a
brief power outage.
BIOS
Acronym for basic input/output system. Your
computer's BIOS contains programs stored on a flash
memory chip. The BIOS controls the following:
communications between the microprocessor and
peripheral devices, such as the keyboard and the video
adapter, and miscellaneous functions, such as system
messages.
BIOS Configuration Utility
The BIOS Configuration Utility configures and
maintains RAID disk groups and virtual disks, and
manages the RAID system. Because the utility resides
in the controller BIOS, its operation is independent of
the operating systems on your system. The BIOS
Configuration Utility, also known as Ctrl-R, is built
on elements called controls. Each control performs a
function. The functions include procedures you can
use to configure physical disks and virtual disks.
C
Cache
Fast memory that holds recently accessed data. Using
cache speeds subsequent access to the same data. It is
most often applied to processor-memory access but
also can be used to store a copy of data accessible over
a network. When data is read from or written to main
memory, a copy is also saved in cache memory with the
associated main memory address. The cache memory
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