Glossary
g-13
Glossary
director An intelligent, highly-available, Fibre Channel switch providing
any-to-any port connectivity between nodes (end devices) on a
switched fabric. The director sends data transmissions (data frames)
between nodes in accordance with the address information present in
the frame headers of those transmissions.
diskette A thin magnetic disk enclosed in a plastic jacket, which is removable
from a computer and is used to store and transport data (D).
diskette drive The hardware mechanism by which a computer reads data from and
writes data to removable diskettes (D).
DNS name Domain name system or domain name service. Host or node name
for a device or managed product that is translated to an Internet pro-
tocol (IP) address through a domain name server.
domain A Fibre Channel term describing the most significant byte in the node
port (N_Port) identifier for the Fibre Channel device. It is not used in
the Fibre Channel small computer system interface (FC-SCSI) hard-
ware path ID. It is required to be the same for all SCSI targets logically
connected to a Fibre Channel adapter.
domain ID Domain identifier. A number that uniquely identifies a switch in a
multiswitch fabric. A distinct domain ID is automatically allocated to
each switch in the fabric by the principal switch. The preferred
domain ID is the domain ID value that a switch requests from the
principal switch. If the value has not been allocated to another switch
in the fabric, it will be granted by the principal switch and will
become the requesting switch’s active domain ID. The active domain
ID is the domain ID that has been assigned by the principal switch
and that a switch is currently using.
domain name server In TCP/IP, a server program that supplies name-to-address transla-
tion by mapping domain name to internet addresses. (D)
DRAM See dynamic random access memory.
drop-down menu A menu that appears when a heading in a navigation bar is clicked on
with the mouse. The objects that appear in the drop-down menus are
organize by their headings in the navigation bar.
duplex In data communication, pertaining to transmission in which data is
sent and received at the same time (D). Contrast with half duplex.