HP 2000fc Reference Manual page 305

controller enclosure An enclosure that contains disk drives and one or two controller
modules. See controller module.
controller module A FRU that contains: a Storage Controller processor; a Management
Controller processor; a SAS expander and Expander Controller
processor; management interfaces; a LAN subsystem; cache protected
by a capacitor pack and Compact Flash memory; host, expansion,
management, and service ports; and midplane connectivity. In a
controller enclosure, the upper controller module is designated A and
the lower one is designated B.
copy-on-write
(COW) A technique for maintaining a point in time copy of a collection of data
by copying only data that is modified after the instant of replicate
initiation. The original source data is used to satisfy read requests for
both the source data itself and for the unmodified portion of the point in
time copy. (SNIA)
See also snap pool.
CPLD Complex programmable logic device. A generic term for an integrated
circuit that can be programmed in a laboratory to perform complex
functions.
CPU Central processing unit. The CPU is where most calculations take
place, and the type of CPU in a controller module affects its
performance capability. In MSA2000 Family storage systems, CPU is
also referred to as the Storage Controller processor or the RAID
controller processor.
DAS See direct attach storage (DAS).
data host A host that reads/writes data to the storage system. The MSA2012fc or
MSA2012sa can be directly connected to multiple data hosts for direct
attach storage (DAS). The MSA2012fc or MSA2012i can be connected
to multiple data hosts through switches for a storage area network
(SAN).
Glossary 305