User manual

Glossary
57
Mirroring
RAID level 1, or mirroring provides redundancy by writing
identical data to each member disk of the array, leaving a
ÒmirroredÓ copy on each disk. Mirroring remains popular
because of its simplicity and high level of data availability. Level
1 operates with two or more disks that may use parallel access for
high data-transfer rates when reading, but more commonly
operate independently to provide high I/O transaction rates.
Level 1 provides very good data reliability and improves
performance for read-intensive applications but at relatively high
cost.
NT domain
An NT domain is an administrative grouping of hosts on a
WIndows Network which supports a centralized administration
of user accounts.
NT domain integration
The process on the NASRaQ where user accounts are kept in sync
with an NT PDC.
Packet
The unit of data that is routed between an origin and a
destination on the Internet or any other packet-switched
network.
Primary Domain Controller (PDC)
In a Windows NT Server domain, the PDC is the computer
running Windows NT Server that authenticates NT domain
logons and maintains the directory database of users and groups
for an NT domain. The PDC tracks changes made to accounts of
all computers on a domain. It is the only computer to receive
these changes directly. A NT domain has only one PDC. The PDC
may keep multiple BDCÕs and NASRaQÕs synchronized.
RAID
Redundant Array of Independent Disks (RAID) technology
satisÞes mass storage and high availability requirements for
general purpose data processing, database and Þle server
applications. See also striping (RAID level 0) and mirroring
(RAID level 1).
Server
A system program that awaits and services requests from client
programs across a network.