Glossary-8
Plug-in units (PIUs)
Self-contained assemblies that are easily installed in the 8400 system cabinet or
expander cabinet. There are PIUs for the XMI bus, the Fu bus, PCI/EISA
buses, as well as for StorageWorks disks and batteries.
Power regulators
The AlphaServer 8400 system can have H7264 single-phase power regulators,
H7263-AA/AB three-phase power regulators, or H7263-AC/AD three-phase
power regulators, which allow battery backup. The H7263 is required to support
N+1 redundancy. Plug-in units are powered by the system, but in addition, bus
PIUs have their own power regulators. Batteries supply power to the 8400 system
cabinet for approximately 11 minutes (3 to 4 minutes for the AlphaServer 8200
system). Expander cabinets have their own supply.
RAID (Redundant Array of Independent Disks)
A set of storage techniques devised to increase the availability and performance of
a storage subsystem.
Reset sequence
A process leading to the execution of a copy of the console firmware from
memory. Purpose is to test the machine, establish the console environment,
indicate that the console is executing, and dispatch to entry handling procedures.
Power-up testing executes from the backup cache, a boot processor is determined,
which creates the HWRPB and copies the console image from ROM/cache to
memory. Registers are set to their default values, and internal console data
structures are initialized. After power-up the secondary processors also use the
console code from memory.
SCSI (Small Computer System Interface)
An industry-standard interface for connecting disks and other peripheral devices to
computer systems.
SCSI PIU
Houses SCSI based disks and tapes inside 8400 system and expander cabinets
(BA655).
SRM (serial ROM) code
The initialization code that bootstraps the main console/diagnostic firmware.
StorageWorks
DIGITAL’s family of module data storage products that allows customers to
design and configure their own storage subsystems. Components include power,
packaging, cabling, devices, controllers, and software. Devices and array
controllers can be integrated in StorageWorks enclosures to form storage
subsystems.
