R

RAID-5 volume

A fault-tolerant volume with data and parity striped intermittently across three or more physical disks. Parity is a calculated value that is used to reconstruct data after a failure. If a portion of a physical disk fails, Windows recreates the data that was on the failed portion from the remaining data and parity. You can create RAID-5 volumes only on dynamic disks on computers running the Windows 2000 Server or Windows Server 2003 families of operating systems. You cannot mirror or extend RAID-5 volumes . In Windows NT 4.0, a RAID-5 volume was known as a striped set with parity . See also dynamic disk; dynamic volume; fault tolerance.

Redundant Array of Independent Disks (RAID)

A method used to standardize and categorize fault-tolerant disk systems. RAID levels provide various mixes of performance, reliability, and cost. Some servers provide three of the RAID levels: Level 0 (striping), Level 1 (mirroring), and Level 5 (RAID-5). See also fault tolerance; RAID-5 volume.

registry

A database repository for information about a computer s configuration. The registry contains information that Windows continually references during operation, such as:

-Profiles for each user

-The programs installed on the computer and the types of documents that each can create

-Property settings for folders and program icons

-What hardware exists on the system

-Which ports are being used

The registry is organized hierarchically as a tree, and it is made up of keys and their subkeys, hives, and entries.

See also key; subkey .

registry key

An identifier for a record or group of records in the registry. See also registry.

remote access policy

A set of conditions and connection parameters that define the characteristics of the incoming connection and the set of constraints imposed on it. Remote access policy determines whether a specific connection attempt is authorized to be accepted.

remote access server

A Windows-based computer running the Routing and Remote Access service and configured to provide remote access.

Remote Authentication Dial-In User Service (RADIUS)

A security authentication protocol based on a client/server model and widely used by Internet service providers (ISPs). RADIUS is the most popular means of authenticating and authorizing dial- up, virtual private network (VPN), wireless, and authenticating switch clients today. A RADIUS client is included in the Routing and Remote Access service that ships with the Windows Server 2003 family. A RADIUS server and proxy, named Internet Authentication Service (IAS), is included in Windows Server 2003, Standard Edition; Windows Server 2003, Enterprise Edition; and Windows Server 2003, Datacenter Edition. See also authorization; Internet Authentication Service (IAS); tunnel; virtual private network (VPN).

Remote Boot Floppy Generator (Rbfg.exe)

A tool that generates a Remote Installation Services (RIS) boot floppy disk. A RIS boot floppy disk is used by RIS client computers to initiate a network boot to a RIS server for remote operating system installation on clients that cannot use Pre-Boot eXecution Environment (PXE). See also Remote Installation Services (RIS).

Remote Installation Preparation wizard (RIPrep.exe)

A component in Remote Installation Services that is used to create operating system images and to install them on the RIS server. See also Remote Installation Services (RIS).

Remote Installation Services (RIS)

Software services that allow an administrator to set up new client computers remotely, without having to visit each client. The target clients must support remote booting.

Remote Installation Services setup (RISetup.exe)

A component in Remote Installation Services that is used to set up the RIS server. See also Remote Installation Services (RIS).

repackaging

The process of converting an earlier version of an application to take advantage of many Windows Installer features, including the ability to advertise the application to users, the ability of the software to repair itself if essential files are deleted or corrupted, and the ability of users to install the application with elevated privileges.

replica

In Active Directory replication, one instance of a logical Active Directory partition that is synchronized by means of replication between domain controllers that hold copies of the same directory partition. Replica can also refer to an instance of an object or attribute in a distributed directory.

In the File Replication service (FRS), a computer that has been included in the configuration of a specific replica set.

reservation

A specific IP address within a scope permanently reserved for leased use to a specific DHCP client. Client reservations are made in the DHCP database using DHCP Manager and based on a unique client device identifier for each reserved entry. See also Dynamic Host Configuration Protocol (DHCP); IP address; lease; scope.

resource

For Resource Manager in Microsoft Provisioning Framework (MPF), a consumable entity such as disk space, IP addresses, or mailboxes that can be assigned to a consumer.

restructure

To change an Active Directory forest infrastructure. Restructuring implies that Active Directory objects are migrated between domains or forests. See also Active Directory; forest; migrate.

RIS

See definition for Remote Installation Services (RIS).

rollback

The removal of the updates performed by one or more partially completed transactions. Rollbacks are required to restore the integrity of a database after an application, database, or system failure.

root

The highest or uppermost level in a hierarchically organized set of information. The root is the point from which further subsets are branched in a logical sequence that moves from a broad or general focus to narrower perspectives. See also DFS root; root hints; root target.

root domain

The beginning of the DNS namespace. In Active Directory, the initial domain in an Active Directory tree. Also, the initial domain of a forest. See also Active Directory; domain; Domain Name System (DNS); forest; namespace.

root hints

DNS data stored on a DNS server that identifies the authoritative DNS servers for the root zone of the DNS namespace. The root hints are stored in the file Cache.dns, located in the systemroot \System32\Dns folder. See also DNS server; Domain Name System (DNS); systemroot.

root target

The mapping destination of a DFS root, which corresponds to a shared folder on a server. See also DFS root; target.

router

A device or computer that forwards packets between interfaces based on a network layer destination address. For example, an Internet Protocol (IP) router forwards IP packets based on the destination IP address in the IP header. Routers typically use a routing table, which contains a series of entries for destinations and the corresponding next -hop address and interface to use to forward a packet to its eventual destination. See also local area network (LAN); routing; wide area network (WAN).

routing

The process of forwarding a packet through an internetwork from a source host to a destination host. See also host; packet.

Routing Information Protocol (RIP)

An industry standard, distance vector routing protocol used in small- to medium- sized Internet Protocol (IP) and Internetwork Packet Exchange (IPX) internetworks. See also Internet Protocol (IP); Internetwork Packet Exchange (IPX); protocol.

routing protocol

Any of several protocols that enable the exchange of routing table information between routers. Typically, medium- to large-sized TCP/IP internetworks implement routing protocols to simplify the administration of routing tables. See also router; routing; routing table.

routing table

A database of routes containing information on network destinations, next-hop addresses and interfaces, and metrics for reachable network segments on an internetwork.