ClearPath IX Systems Installation and Configuration Guide

Glossary
disk mirroring
Fault-tolerant technique that writes data simultaneously to two disks using the same disk
controller. The disks operate in tandem, constantly storing and updating the same files.
Mirroring alone does not ensure data protection. If both disks fail at the same time, data is
still lost.
Distributed Component Object Model (DCOM)
The Microsoft model for distributed object computing. The nondistributed component
object model (COM) is the technology underlying Object Linking and Embedding (OLE).
DCOM extends this technology to multisystem usage and is the technology underlying
ActiveX technology.
distributed transaction processing (DTP)
(X/Open) A form of processing in which multiple application programs update multiple
resources (such as databases) in a coordinated manner. Programs and resources can
reside on one or more computers across a network. See also global transaction, X/Open
Distributed Transaction Processing model.
DLL
DNS
domain
See dynamic link library.
See domain name system.
In Windows NT, a collection of computers (defined by the network administrator) that
share a common directory database. Each domain has a unique name. Users have only
one account in the domain, thus simplifying sign-on and administration. Users log on to
the domain, not to individual servers in the domain. See also directory database and
domain controller.
domain controller
A computer in a Windows NT Server domain that uses information in the directory
database to manage all aspects of user-domain interactions, including authentication of
users logging on to domain accounts. A domain has one primary domain controller (PDC)
and one or more backup domain controllers (BDC). See also directory database, primary
domain controller (PDC), backup domain controller (BDC), and member server.
domain name
A hierarchical name that identifies a host system or portion of a network in a TCP/IP
environment. Each domain name is composed of subnames or labels that identify
successive levels in a tree structure. A name that includes the local host name and all
levels (for example, hlcnt.rsvl.unisys.com) is referred to as a fully qualified domain name.
domain name system (DNS)
(Also domain name server) The mechanism that implements a hierarchical naming scheme
known as domain names for TCP/IP networks. A domain name consists of a sequence of
subnames separated by periods that identify successive levels in directory structure. This
system maps host names to IP addresses.
DRS
Abbreviation for disk-resident system.
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