The following terms are defined in [MS-GLOS]:
globally unique identifier (GUID)
The following terms are specific to this document:
AND group: A conjunctive clause in a disjunctive normal form (DNF) formula. For example, in the formula (A AND B) OR (A AND C), the clauses "(A AND B)" and "(A AND C)" are AND groups.
client computer: A computer that gets its updates from an update server. A client can be a desktop computer, a server, or the update server.
ClientIdString: A globally unique string that identifies a client machine to the update server. It is between 1 and 255 characters in length and contains only the letters a-z, the digits 0-9, or the hyphen.
client Web service: A Web service on the update server that enables clients to obtain updatemetadata.
conjunctive normal form (CNF): A logical formula consisting of a conjunction of disjunctions of terms in which no disjunction contains a conjunction. For example, A OR (B AND C) is not in CNF, whereas the equivalent (A OR B) AND (A OR C) is in CNF.
content: A package that contains all the associated files for an update that is to be installed on a client computer.
deployment: An administratively specified decision to make a specific updaterevision available to a specific target group.
disjunctive normal form (DNF): A logical formula consisting of a disjunction of conjunctions of terms in which no conjunction contains a disjunction. For example, A AND (B OR C) is not in DNF, whereas the equivalent (A AND B) OR (A AND C) is in DNF.
locale: A set of language-related preferences that influence the presentation of user interface elements, such as human-readable strings.
man-in-the-middle: A computer security attack in which an attacker is able to read, insert, and modify at-will messages between two parties without either party knowing that the link between them is compromised. The attacker must be able to observe and intercept messages going between the two parties.
metadata: XML-formatted data that defines the characteristics of an update, including its title, description, rules for determining whether the update is applicable to a client computer, and instructions for installing the updatecontent.
Microsoft Windows Installer (MSI): A file format that contains information used by Windows Installer to install software and software updates. For more information, see [MSI].
prerequisite: A relationship from a revision to a set of updates specified in conjunctive normal form (CNF). For example, (U6 | U8) & (U2) & (U5 | U3). A client will not treat a revision as requiring installation unless its prerequisites are satisfied (that is, at least one update in each CNF disjunctive clause is installed on the client).
prerequisite graph: A directed graph with revisions as vertices and prerequisite relationships as edges.
QFE: A small update designed to address a specific software bug.
reporting Web service: A Web service used by clients to report status to the server.
revision: A specific version of an update that is identified by a combination of a GUID UpdateID and a 32-bit RevisionNumber.
revision ID: A compact server-assigned, 32-bit identifier for a revision that is used to identify the revision during client/server communication.
self-update: A process by which a client first communicates with the update server to detect updates to the executable files that implement the client role on computers running Windows, and then applies those updated executable files before carrying on further communication.
self-update content directory: A location on the update server containing update content files for the update client that is identified by an HTTP URL and exposed to clients.
SimpleAuth Web service: A Web service on the server that is used to authorize what clients should get metadata for what revisions.
Simple Object Access Protocol (SOAP): An XML-based protocol for exchanging information in distributed systems, as specified in [SOAP1.1].
target group: A named collection of client computers whose members are defined administratively.
update: The combination of metadata and associated content for a software update.
update category: A group of updates. Each update belongs to zero or more update categories. An update category can be a product category that contains updates for a particular product, or a classification category that contains updates of a particular classification (for example, all security updates).
update content directory: A location on the update server containing update content files that is identified by an HTTP URL and exposed to clients.
update server: A computer that implements the Windows Server Update Services: Client-Server Protocol to provide updates to client computers and other update servers.
virtual directory: An HTTP URL that represents the root of a location to which content may be published administratively.
Web Service Definition Language (WSDL): An XML-based standard for specifying message-based distributed services, as specified in [WSDL].
Windows Server Update Services (WSUS): An optional component of Windows 2000 Server, Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 that may be installed to enable a computer to operate as an update server. See [WSUS].
Windows Update Agent (WUA): A component originally introduced in the Windows 2000 Server SP3 operating system that enables a computer to operate as a client of an update server.
MAY, SHOULD, MUST, SHOULD NOT, MUST NOT: These terms (in all caps) are used as specified in [RFC2119]. All statements of optional behavior use either MAY, SHOULD, or SHOULD NOT.