DEC VAXstation 3100 Owner's Manual page 195

H4000 transceiver
An Ethernet transceiver used to connect standard Ethernet communications
equipment to standard Ethernet. The H4000 supports a heartbeat signal used in
network diagnostics.
H4000-BA transceiver
An H4000-BA is an Ethernet transceiver used to connect standard Ethernet
commimications equipment to standard Ethernet. The H4000-BA does not support
a heartbeat signal, because the heartbeat disrupts DELNI/DEMPR performance.
See transceiver.
H4005 transceiver
A smaller and less expensive transceiver than the H4000 and H4000-BA. Its small
dimensions permit installation in constricted spaces such as cable trays.
hard disk
A hard disk resides permanently inside a disk drive.
tiard error
A nonrecoverable error.
hardware
The physical equipment, both mechanical and electrical, that makes up a system.
Compare softiware.
hardware Ethernet address
The imique Ethernet physical address associated with a particular Ethernet
communications controller. It is a combination of 12 characters, including letters
(A to F) and numbers (0 to 9). The characters are grouped in six pairs; each pair
is separated by a hyphen (-). For example, 08-00-2B-04-FD-C9 is a valid Ethernet
address.
head
The part of a hard disk drive, or tape drive that reads, records, and erases data.
Also called read/write head.
Glossary-9