16 O

object: (1) A set of attributes, each with its associated values. Two attributes of an object have special significance:

  • Identifying attribute: A designated single-valued attribute appears on every object; the value of this attribute identifies the object. For the set of objects in a replica, the values of the identifying attribute are distinct.

  • Parent-identifying attribute: A designated single-valued attribute appears on every object; the value of this attribute identifies the object's parent. That is, this attribute contains the value of the parent's identifying attribute, or a reserved value identifying no object. For the set of objects in a replica, the values of this parent-identifying attribute define a tree with objects as vertices and child-parent references as directed edges with the child as an edge's tail and the parent as an edge's head.

Note that an object is a value, not a variable; a replica is a variable. The process of adding, modifying, or deleting an object in a replica replaces the entire value of the replica with a new value.

As the word replica suggests, it is often the case that two replicas contain "the same objects". In this usage, objects in two replicas are considered the same if they have the same value of the identifying attribute and if there is a process in place (replication) to converge the values of the remaining attributes. When the members of a set of replicas are considered to be the same, it is common to say "an object" as shorthand referring to the set of corresponding objects in the replicas.

(2) In Active Directory, an entity consisting of a set of attributes, each attribute with a set of associated values. For more information, see [MS-ADTS].

(3) In COM, a software entity that implements the IUnknown interface and zero or more additional interfaces that may be obtained from each other using the IUnknown interface. A COMobject can be exposed to remote clients via the DCOM protocol, in which case it is also a DCOMobject (4).

(4) In the DCOM protocol, a software entity that implements one or more object remote protocol (ORPC) interfaces and which is uniquely identified, within the scope of an object exporter, by an object identifier (OID) (1). For more information, see [MS-DCOM].

object class: (1) A predicate defined on objects that constrains their attributes. Also an identifier for such a predicate.

(2) A set of restrictions on the construction and update of objects. An object class can specify a set of must-have attributes (every object of the class must have at least one value of each) and may-have attributes (every object of the class may have a value of each). An object class can also specify the allowable classes for the parent object of an object in the class. An object class can be defined by single inheritance; an object whose class is defined in this way is a member of all object classes used to derive its most specific class. An object class is defined in a classSchema object.

(3) In COM, a category of objects (3) identified by a CLSID, members of which can be obtained through activation of the CLSID.

(4) In the DCOM protocol, a category of objects (4) identified by a CLSID, members of which can be obtained through activation of the CLSID. An object class is typically associated with a common set of interfaces that are implemented by all objects in the object class.

object class inheritance: The process of defining one object class in terms of its variations from an existing object class. The may-have, must-have, and possible superiors restrictions of an object class are all inherited.

object class name: The lDAPDisplayName of the classSchema object of an object class. The correspondence between Lightweight Directory Access Protocol (LDAP) display names and numeric object identifiers (OIDs) is specified in [MS-ADTS].

object exporter: An object container (for example, process, machine, thread) in an object server. Object exporters are callable using RPC interfaces, and they are responsible for dispatching calls to the objects they contain.

object exporter identifier (OXID): A 64-bit number that uniquely identifies an object exporter within an object server.

objectGUID: (1) The attribute on an object whose value is a GUID that uniquely identifies the object. The value of objectGUID is assigned when an object is created and is immutable thereafter. The integrity of both object references between naming contexts (NCs) and of replication depends on the integrity of the objectGUID attribute.

(2) The GUID of an Active Directory object. For more information, see [MS-ADTS].

Object ID: See ObjectID.

ObjectID: A unique identifier that represents the identity of a file within a file system volume. For more information, see [MS-DLTM].

object identifier (OID): (1) In the context of an object server, a 64-bit number that uniquely identifies an object.

(2) In the context of a directory service, a number identifying an object class or attribute. Object identifiers are issued by the ITU and form a hierarchy. An OID is represented as a dotted decimal string (for example, ""). For more information on OIDs, see [X660] and Appendix A of [RFC3280]. OIDs are used to uniquely identify certificate templates available to the certificate authority (CA). Within a certificate, OIDs are used to identify standard extensions as covered in [RFC3280] section 4.2.1.x, as well as non-standard extensions.

(3) In the Lightweight Directory Access Protocol (LDAP), a sequence of numbers in a format specified by [RFC1778]. In many LDAP directory implementations, an OID is the standard internal representation of an attribute. In the directory model used in [MS-ADTS], the more familiar ldapDisplayName represents an attribute.

(4) In the context of Abstract Syntax Notation One (ASN.1), an object identifier, as specified in [ITUX680].

(5) A variable-length identifier from a namespace administered by the ITU. Objects, protocols, and so on that make use of ASN.1 or Basic Encoding Rules (BER), Distinguished Encoding Rules (DER), or Canonical Encoding Rules (CER) encoding format leverage identities from the ITU. For more information, see [ITUX680].

object of class x (or x object): An object o such that one of the values of its objectClass attributes is x. For instance, if objectClass contains the value user, o is an object of class user. This is often contracted to "user object".

object reference: (1) An attribute value that references an object. Reading a reference gives the distinguished name (DN) of the object.

(2) In the DCOM protocol, a reference to an object (4), represented on the wire as an OBJREF. An object reference enables the object to be reached by entities outside the object'sobject exporter.

object remote procedure call (ORPC): A remote procedure call whose target is an interface on an object. The target interface (and therefore the object) is identified by an interface pointer identifier (IPID).

object resolver: A service in an object server that supports instantiating objects, obtaining remote procedure call (RPC) binding information for object exporters, and managing object lifetimes. Object resolvers may be reachable via well-known or dynamic RPC endpoints.

object server: An execution environment that contains a particular object resolver service and its associated object exporters.

object UUID: A UUID that is used to represent a resource available on the remote procedure call (RPC) servers. For more information, see [C706].

OBJREF: The marshaled form of an object reference.

OEM character: See original equipment manufacturer (OEM) character.

OEM character set: See original equipment manufacturer (OEM) character set.

OEM code page: See original equipment manufacturer (OEM) code page.

offline: An operational state applicable to volumes and disks. In the offline state, the volume or disk is unavailable for data input/output (I/O) or configuration.

OID: See object identifier.

OleTx: A comprehensive distributed transaction manager processing protocol that uses the protocols specified in the following document(s): [MS-CMPO], [MS-CMP], [MS-DTCLU], [MS-DTCM], [MS-DTCO], [MC-DTCXA], [MS-TIPP], and [MS-CMOM].

one-way authentication: An authentication mode in which only one party verifies the identity of the other party.

one-way function (OWF): The calculation of a hash of the password using the Rivest-Shamir-Adleman (RSA) MD4 function. OWF is used to refer to the resulting value of the hash operation.

online: An operational state applicable to volumes and disks. In the online state, the volume or disk is available for data input/output (I/O) or configuration.

operating system upgrade: The action of replacing the existing operating system on a computer with a later version of the operating system while maintaining the original configuration and data of that computer.

operational attribute: An attribute that is returned only when requested by name in an Lightweight Directory Access Protocol (LDAP) search request. An LDAP search request requesting "all attributes" does not return operational attributes and their values.

oplock break: An unsolicited request sent by a Server Message Block (SMB) server to an SMB client to inform the client to change the oplock level for a file.

opnum: An operation number or numeric identifier that is used to identify a specific remote procedure call (RPC) method or a method in an interface. For more information, see [C706] section or [MS-RPCE].

opportunistic lock (oplock): A mechanism designed to allow clients to dynamically alter their buffering strategy in a consistent manner to increase performance and reduce network use. The network performance for remote file operations may be increased if a client can locally buffer file data, which reduces or eliminates the need to send and receive network packets. For example, a client may not have to write information into a file on a remote server if the client knows that no other process is accessing the data. Likewise, the client may buffer read-ahead data from the remote file if the client knows that no other process is writing data to the remote file.

There are three types of oplocks:

  • Exclusive oplock allows a client to open a file for exclusive access and allows the client to perform arbitrary buffering.

  • Batch oplock allows a client to keep a file open on the server even though the local accessor on the client machine has closed the file.

  • Level II oplock indicates that there are multiple readers of a file and no writers. Level II Oplocks are supported if the negotiated SMB Dialect is NT LM 0.12 or later.

When a client opens a file, it requests the server to grant it a particular type of oplock on the file. The response from the server indicates the type of oplock granted to the client. The client uses the granted oplock type to adjust its buffering policy.

optical media drive: A drive that controls the positioning, reading, and writing of removable media on optical disks such as CD-ROMs and DVDs.

oriented tree: A directed acyclic graph such that for every vertex v, except one (the root), there is a unique edge whose tail is v. There is no edge whose tail is the root. For more information, see [KNUTH1] section

original equipment manufacturer (OEM) character: An 8-bit encoding used in MS-DOS and Windows operating systems to associate a sequence of bits with specific characters. The ASCII character set maps the letters, numerals, and specified punctuation and control characters to the numbers from 0 to 127. The term "code page" is used to refer to extensions of the ASCII character set that map specified characters and symbols to the numbers from 128 to 255. These code pages are referred to as OEM character sets. For more information, see [MSCHARSET].

original equipment manufacturer (OEM) character set: A character encoding used where the mappings between characters is dependent upon the code page configured on the machine, typically by the manufacturer.

original equipment manufacturer (OEM) code page: A code page used to translate between non-Unicode encoded strings and UTF-16 encoded strings.

originating update: An update that is performed to an NC replica via any protocol except replication. An originating update to an attribute or link value generates a new stamp for the attribute or link value.

originating write: An update operation that should be replicated to other replicas. The originating write changes the server state. The inputs of the operation are the DSNAME of the object, the old value of replication metadata, and the list of modified attributes and values. The result of the operation is the new replication metadata stamped on the object.

originator GUID: A GUID that is associated with each replica member. All change orders produced by a given replica member carry the replica member's originator GUID, which is saved in the IDTable. The originator GUID is not the same as the member GUID, which is the objectGUID of the NT File Replication Service (NTFRS) member object in Active Directory. For more information, see [MS-ADTS].

ORPC extension: An out-of-band (not part of the explicit method signature), GUID-tagged binary large object (BLOB) of data that is sent or received in an object remote procedure call (ORPC) call.

OSF-DCE: The Distributed Computing Environment from the Open Software Foundation. It consists of multiple components, including remote procedure call (RPC), that have been integrated to work closely together.

outbound: Network traffic flowing from the server to the client.

outbound connection: For a given replica member, a component of the NT File Replication Service (NTFRS) member object in Active Directory that identifies outbound partners. An outbound connection exists for each outbound partner.

outbound log (OutLog): A table in the File Replication Service(FRS) database that stores pending change orders to be sent to outbound partners. The changes can originate locally or come from an inbound partner. These change orders are eventually sent to all outbound replica partners.

outbound partner: The partner that receives change orders, files, and folders.

outbound trust: A relationship in which the primary domain trusts another domain to perform operations such as name lookups and authentication.

out-of-band policy application: A protocol exchange between a client and a server in which policy enforcement occurs for some subset of Group Policy settings from Group Policy Objects (GPOs) encountered during some previous policy application exchange. This is referred to as "out-of-band" because, unlike policy application, an out-of-band policy application retrieves settings separately from GPO retrieval.

OXID resolution: The process of obtaining the remote procedure call (RPC) binding information that is required to communicate with the object exporter.