1–2 General Description
Typical Installation
Figure shows the major components, or basic building blocks, of the storage
subsystem that is comprised of the following:
■ One BA370 rack-mountable enclosure.
■ Two controllers, each supported by a cache module.
■ Two External Cache Batteries (ECBs) in one Storage Building Block (SBB),
which provide backup power to the cache modules during a primary power
failure.
■ One environmental monitoring unit (EMU) that monitors the subsystem’s
environment and alerts the controller of equipment failures that could cause an
abnormal environment.
■ One Power Verification and Addressing (PVA) module that provides a unique
address to each enclosure in an extended subsystem.
■ Six I/O modules that integrate the SBB shelf with either an 8-bit single-ended,
16-bit single-ended, or 16-bit differential SCSI bus
■ Two cache modules, which support nonvolatile memory and dynamic cache
policies to protect the availability of its unwritten (write-back) data
