HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and Configuration Guide

Glossary
Glossary–10 HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and
Configuration Guide
host adapter
A device that connects a host system to a SCSI bus. The host adapter
usually performs the lowest layers of the SCSI protocol. This function
may be logically and physically integrated into the host system.
HBA
Host bus adapter
host
compatibility
mode
A setting used by the controller to provide optimal controller
performance with specific operating systems. This improves the
controller performance and compatibility with the specified operating
system.
hot disks
A disk containing multiple hot spots. Hot disks occur when the
workload is poorly distributed across storage devices which prevents
optimum subsystem performance. See also hot spots.
hot spots
A portion of a disk drive frequently accessed by the host. Because the
data being accessed is concentrated in one area, rather than spread
across an array of disks providing parallel access, I/O performance is
significantly reduced. See also hot disks.
hot swap or
hot-pluggable
A method of device replacement that allows normal I/O activity on a
device bus to remain active during device removal and insertion. The
device being removed or inserted is the only device that cannot perform
operations during this process. See also cold swap and warm swap.
hub
A device (concentrator) which performs some or all of the following
functions:
• Automatic insertion of operational loop devices without disrupting
the existing configuration.
• Automatic removal of failed loop devices without impacting the
existing configuration.
• Provides a centralized (star) wiring configuration and maintenance
point.
• Provides central monitoring and management.
IBR
Initial Boot Record.
ILF
Illegal function.
INIT
Initialize input and output.