logical drive
capacity extension
See capacity extension.
online spare
A disk in a fault-tolerant system that normally contains no data. When another disk in the array
fails, the controller rebuilds the data that was on the failed disk to the online spare. Also known
as a hot spare.
PCIe
An enhanced PCI bus that enables operation at 266 MHz, equivalent to a data throughput of
2.5 GB/s.
rebuild
See Automatic Data Recovery.
Redundant Array
of Independent
Disks (RAID)
A form of fault tolerance. RAID 0 (no fault tolerance) uses data striping to distribute data evenly
across all physical disks in the array, but has no redundant data. RAID 1+0 (disk mirroring)
duplicates data from one disk onto a second disk. RAID 5 (distributed data guarding) distributes
parity data across all disks in the array, and uses the parity data and data on remaining disks
to reconstruct data from a failed disk. RAID ADG (advanced data guarding) is similar to RAID
5, but uses two independent sets of parity data.
SCSI ID
A unique ID number assigned to each SCSI device connected to a SCSI bus. The ID number
determines the device priority on the SCSI bus; ID 7 is the highest priority and is always assigned
to the SCSI controller.
Self-Monitoring,
Analysis, and
Reporting
Technology
(S.M.A.R.T.)
Technology co-developed by HP and the physical disk industry that provides warning of imminent
disk failure. S.M.A.R.T. enables HP to offer Pre-Failure Warranty replacement of physical disks.
S.M.A.R.T. supersedes the disk parameter tracking feature that was previously used, because the
self-monitoring routines used in S.M.A.R.T. are more accurate than the disk parameter tracking
tests. The self-monitoring routines are customized for each specific disk type and have direct
access to internal performance, calibration, and error measurements.
Simple Network
Management
Protocol (SNMP)
Governs network management and the monitoring of network devices and functions.
Single-Ended (SE)
A type of SCSI signaling that enables a maximum transfer rate of 40 MB/s. Conforms to the
Wide-Ultra SCSI standard. Now being phased out in favor of LVD technology.
spare
See online spare.
striping
See data striping.
surface analysis
See Auto-Reliability Monitoring.
130 Glossary
