Owner manual

(model 6780). The layered topology can scale by adding cluster switch layers or zones.
The layered topology supports up to four layers and three zones.
See also star topology.
light-emitting diode (LED)
A semiconductor device that emits light from its surface. LEDs are used as indicator
lights on CRUs and FRUs in NonStop S-series servers.
line
The specific hardware path over which data is transmitted or received. A line can also
have a process name associated with it that identifies an input/output process (IOP) or
logical device associated with that specific hardware path.
line interface unit (LIU)
A dual-ported unit consisting of two parts: a communications line interface processor
(CLIP) and a line interface module (LIM). An LIU can communicate with either the
primary or the backup processor, providing fault tolerance. When it is a component of the
communications subsystem, an LIU communicates with either processor through either
of a pair of communications interface units (CIUs).
link
A communications path between two entities.
load
To transfer the NonStop Kernel operating system image or a program from storage
(typically disk) into processor memory so that the operating system or program can run.
local area network (LAN)
A network that is located in a small geographical area and provides a high-bandwidth,
low-cost medium to which low-cost nodes can be connected. One or more LANs can be
connected to the system such that the LAN users can access the system as if their
workstations were connected directly to it.
See also wide area network (WAN) and ServerNet system area network (ServerNet
SAN).
logic board (LB)
A printed wiring assembly (PWA) on which computer circuits (chips and wiring) are
mounted. One type of logic board is a processor and memory board (PMB). Another type
is a multifunction I/O board (MFIOB).
logical device number
A number that identifies a particular I/O device in the system. Logical device numbers
are assigned to physical I/O devices.