NonStop System Glossary

quality power
The attributes and configuration of the power-distribution systems installed within a facility that best
serve the power needs of that facility’s electrical equipment (for example, computer systems, air
conditioning, and so on), providing the minimum possible disruption to equipment operation.
QUICC
See quad-integrated communications controller (QUICC).
R
R1
See ServerNet router 1.
R2
See ServerNet router 2.
R3
See ServerNet router 3.
raceway
An enclosed channel used to hold wires, cables, or busbars. Most raceways have removable tops
to facilitate the installation or removal of their contents.
rack
A metal structure that has four columns, to which slides or rails that hold computer equipment can
be fastened. See also frame.
radio frequency interference (RFI)
Forms of conducted or radiated interference that might appear in a facility as either normal or
common-mode signals. The frequency of the interference can range from the kilohertz to gigahertz
range. However, the most troublesome interference signals are usually found in the kilohertz to
low megahertz range. At present, the terms radio frequency interference and electromagnetic
interference (EMI) are usually used interchangeably.
RDMA
Remote direct memory access.
read-only file system
A file system with implementation-defined characteristics that restrict changes to the files within that
file system.
read/write head
An electromagnet that can pick up (read) electronic pulses and record (write) electronic pulses on
a magnetic disk or tape. The electronic pulses are interpreted by the processor as binary data.
See also disk drive and tape drive.
R 155