HP NetRAID 1Si Controller - Manual (Page 150)

Glossary
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Reconstruction is only permitted on a logical drive that occupies a single array
and is the only logical drive in the array. You cannot use online capacity
expansion on logical drives that span arrays (RAID levels 10, 30, or 50).
Channel: An electrical path for the transfer of data and control information
between a disk and a disk adapter or controller.
Consistency Check: An examination of the disk system on a stripe-by-stripe basis
to verify that data and parity are valid. Inconsistent data or parity is repaired if
enough redundant/valid data remains.
Degraded: A logical drive that has decreased in performance due to a failed
physical drive. The data on the logical drive remains available, but no additional
redundancy is provided.
Disk: A physical drive. A hard disk drive. A non-volatile, randomly addressable,
rewritable mass storage device.
Disk Array: A collection of disks from one or more disk subsystems combined
with array management hardware and software. It controls the disks and presents
them to the operating system as one or more logical disks.
Failed Drive: A drive that has ceased to function, that consistently functions
improperly, or that has been changed to the Fail state.
Fast SCSI: A variant on the SCSI-2 bus. It uses the same 8-bit bus as the original
SCSI-1, but runs at up to 10 MB/s, (double the speed of SCSI-1).
Firmware: Software stored in read-only memory (ROM) or Programmable ROM
(PROM). Firmware is responsible for the behavior of a system when it is first
switched on.
Format: The process of writing zeros to all data fields in a physical drive (hard
drive) and to map out unreadable or bad sectors. Because most hard drives are
factory formatted, formatting is usually only done if a hard disk generates several
media errors.
GB: A gigabyte; an abbreviation for 1,073,741,824 (2 to the 30th power) bytes;
used for memory or disk capacities.
Hot Spare: An idle, powered/on stand-by disk module ready for use should
another disk module fail. It does not contain any user data. A hot spare can be
dedicated to a single array, or it can be part of the global hot-spare pool for all the
arrays controlled by the adapter. Only one hot spare can be dedicated to a given
array.
When a disk fails, the adapter’s firmware automatically replaces and rebuilds the
data from the failed disk onto the hot-spare disk. Data can only be rebuilt from
logical drives with redundancy (RAID levels 1, 3, 5, 10, 30, or 50; not RAID 0),