NonStop S-Series Operations Guide (G06.27+)

Determining Your System Configuration
HP NonStop S-Series Operations Guide—522459-008
2-2
Terms Used to Describe System Hardware
Components
Terms Used to Describe System Hardware Components
The terms used to describe system-hardware components vary. These terms include:
•
Device
•
Resource
•
Customer-replaceable unit (CRU)
•
Field-replaceable unit (FRU)
Device
A device can be a physical device or a logical device. A physical device is a physical
component of a computer system that is used to communicate with the outside world
or to acquire or store data. A logical device is a process used to conduct input or
output with a physical device.
Resource
The term resource is commonly used in OSM and TSM documentation to refer to
NonStop S-series server components that OSM and TSM software recognizes,
monitors, and controls. Besides hardware components, such as processors, power
supplies, ServerNet adapters, and disk and tape drives, resources also include objects
such as processes and ServerNet fabrics.
Customer-Replaceable Unit (CRU)
A CRU is a system-hardware component that usually can be installed and serviced
(replaced) by customers without using special tools. CRUs typically can be replaced
while the system is running.
CRUs are classified into three categories based on the risk of causing a system outage
if the documented replacement procedure is not followed correctly and on how much
related experience or training a customer should have. For a CRU replacement that is
likely to cause a system outage if not performed correctly (Class 3), HP recommends
replacement by a trained service provider.
Field-Replaceable Unit (FRU)
A FRU is a system-hardware component that can be replaced in the field only by
qualified personnel trained by HP.