Technical data

GL–15
Compaq HSG80 Array Controller ACS Version 8.3 Maintenance and Service Guide
redundancy The provision of multiple interchangeable components to perform a single
function in order to cope with failures and errors. A RAIDset is considered
to be redundant when user data is recorded directly to one member and all
of the other members include associated parity information.
regeneration (1) The process of calculating missing data from redundant data. (2) The
process of recreating a portion of the data from a failing or failed drive
using the data and parity information from the other members within the
storageset. The regeneration of an entire RAIDset member is called
reconstruction. See also reconstruction.
request rate The rate at which requests are arriving at a servicing entity.
RFI Radio frequency interference. The disturbance of a signal by an unwanted
radio signal or frequency.
replacement policy The policy specified by a switch with the SET FAILEDSET command
indicating whether a failed disk from a mirrorset or RAIDset is to be
automatically replaced with a disk from the spareset. The two switch
choices are AUTOSPARE and NOAUTOSPARE.
SBB StorageWorks building block. (1) A modular carrier plus the interface
required to mount the carrier into a standard StorageWorks shelf. (2) any
device conforming to shelf mechanical and electrical standards installed in a
3.5-inch or 5.25-inch carrier, whether it is a storage device or power supply.
SCSI Small computer system interface. (1) An ANSI interface standard defining
the physical and electrical parameters of a parallel I/O bus used to connect
initiators to devices. (2) a processor-independent standard protocol for
system-level interfacing between a computer and intelligent devices
including hard drives, floppy disks, CD-ROMs, printers, scanners, and
others.
SCSI-A cable A 50-conductor (25 twisted-pair) cable generally used for single-ended,
SCSI-bus connections.