IBM TotalStorage SAN140M, Installation And Service Manual

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359 Glossary
H
half-duplex The capability to communicate in both directions over a single
connection, but not simultaneously (except for link control frames).
Contrast with
full-duplex .
Hardware Log
A log recorded at the Element Manager application that displays a
history of FRU removals and replacements (insertions) for a director
or switch.
HBA See host bus adapter .
hexadecimal A computer numbering system with base of sixteen. Valid numbers
use the digits 0 through 9 and characters A through F.
high availability
A director and switch performance feature characterized by
component redundancy and the ability to perform concurrent
maintenance. High-availability systems maximize system uptime
while providing superior reliability, availability, and serviceability.
high speed serial data
connector
A 20-pin serial connector type that provides connectivity to an
ES-1000 Switch GBIC. Contrast with
DB-9 connector .
host bus adapter A logic card that provides a link between a server and storage
subsystem, and that integrates the operating systems and I/O
protocols of both devices to ensure interoperability.
H_Port
See hub port .
HSSDC See high speed serial data connector .
hub
A non intelligent device that connects Ethernet or Fibre Channel
nodes into a logical loop by using a physical star topology.
hub port An arbitrated loop port that provides FC-AL device connectivity to
the ES-1000 Switch. H_Ports are not assigned port addresses and
provide physical connectivity only. Contrast with
fabric loop port .
I
IML
See initial machine load .