DEC 4000 600 series, Owner'S Manual, Page: 229 / 242

ThinWire
Digital’s proprietary Ethernet products used for local distribution
of data communications. Contrast with thickwire.
uninterruptible power supply (UPS)
A battery-backup option that maintains AC power if a power
failure occurs.
UPS
See uninterruptible power supply.
VMScluster system
A highly integrated organization of Digital’s VMS systems
that communicate over a high-speed communications path.
VMScluster configurations have all the functions of single-node
systems, plus the ability to share CPU resources, queues, and
disk storage.
volume shadowing
The process of maintaining multiple copies of the same data on
two or more disk volumes. When data is recorded on more than
one disk volume, you have access to critical data even when one
volume is unavailable. Also called disk mirroring.
warm swap
The shutdown and removal and replacement of a failing DSSI
disk from an active bus.
word
Two contiguous bytes (16 bits) starting on an arbitrary byte
boundary. The bits are numbered from right to left, 0 through
15.
write-enabled
A device is write-enabled when data can be written to it.
Contrast with write-protected.
write-protected
A device is write-protected when transfers are prevented from
writing information to it. Contrast with write-enabled.
Glossary–13