Digital Equipment AlphaServer 2000, Руководство пользователя, Страница: 170 / 196

availability
The amount of scheduled time that a computing system provides
application service during the year. Availability is typically
measured as either a percentage of uptime per year or as system
unavailability, the number of hours or minutes of downtime per
year.
BA350 storage shelf
A StorageWorks modular storage shelf used for disk storage in
some AlphaServer systems.
BA720 enclosure
The enclosure that houses the AlphaServer 2000 deskside
pedestal system.
BA740 enclosure
The enclosure that houses the AlphaServer 2100 large pedestal
system.
BA741 enclosure
The enclosure that houses the AlphaServer 2100 RM
(rackmountable) system and AlphaServer 2100 CAB (cabinet)
system.
backplane
The main board or panel that connects all of the modules in a
computer system.
backup cache
A second, very fast cache memory that is closely coupled with
the processor.
bandwidth
Term used to express the rate of data transfer in a bus or I/O
channel. It is expressed as the amount of data that can be
transferred in a given time, for example, megabytes per second.
battery backup unit
A battery unit that provides power to the entire system enclosure
(or to an expander enclosure) in the event of a power failure.
Another term for uninterruptible power supply (UPS).
Glossary–2