Availability Guide for Application Design

Glossary
Availability Guide for Application Design—525637-004
Glossary-20
RDF
RDF. See Remote Duplicate Database Facility (RDF).
reconfiguration. See reconfiguration outage class.
reconfiguration outage class. An outage class that includes all planned outages.
Examples include downtime required for planned maintenance (such as software
upgrades) and configuration changes (such as adding a new disk or restructuring a
database).
recovery. The returning of a database file back to a consistent state.
reduced instruction-set computing (RISC). A processor architecture based on a relatively
small and simple instruction set, a large number of general-purpose registers, and an
optimized instruction pipeline that supports high-performance instruction execution.
Contrast with complex instruction-set computing (CISC).
relational database. A database in which data is represented as relational tables.
reliability. A measure of how long an application is available before, for some reason, it
becomes unavailable. HP also considers an application to be unavailable if it is running
so slowly that it cannot do the job to the user’s satisfaction, as defined in a service-
level agreement.
Remote Duplicate Database Facility (RDF). The HP software product that assists in
disaster recovery for OLTP production databases, monitors database updates audited
by TMF on a primary system, and applies those updates to a copy of the database on
a remote system.
remote duplicate transaction. A transaction that concurrently executes against two
identical copies of the database. Remote duplicate transactions can be used to provide
a remote, duplicate database for use in disaster recovery or for taking a database
snapshot. See also Remote Duplicate Database Facility (RDF) and database
snapshot.
Remote Server Call/MP (RSC/MP). An HP product that facilitates client/server computing,
allowing PC or workstation applications running under Microsoft Windows software or
the MS-DOS or OS/2 operating system to access Pathway server classes and
Guardian processes.
replicated process. See process replication.
requester. A process or program that runs in the Guardian environment on an HP NonStop
system and requests services from a server process. A requester is a specific type of
client. See also client, server, and requester/server model.
requester/server model. A model for application design that divides the tasks of data input,
data manipulation, and data output between two basic processes: requesters and
servers. See also requester and server.