HP Array Controller HSG V8.7 Software - Manual (Page 26)

1–2 HSG80 User’s Guide
The HSG80 Array Controller Subsystem
Take a few moments to familiarize yourself with the major components
of the HSG80 Array Controller subsystem. Figure 1–1 shows the
components of a typical installation which includes:
n One BA370 rack-mountable pedestal enclosure.
n Two controllers, each supported by their own cache module.
n Two external cache batteries (ECBs) in one Storage Building Block
(SBB), which provide backup power to the cache modules during a
primary power failure.
n One environmental monitoring unit (EMU) that monitors the
subsystem’s environment, and alerts the controller of equipment
failures that could cause an abnormal environment.
n One power verification and addressing (PVA) module that provides
a unique address to each enclosure in an extended subsystem.
n Six I/O modules that integrate the SSB shelf with either an 8-bit
single-ended, 16-bit single-ended, or 16-bit differential SCSI bus.
n Two cache modules, which support nonvolatile memory and
dynamic cache policies to protect the availability of its unwritten
(write-back) data.