This topic describes the technological vocabulary used in the IIS SDK. Many of these terms are familiar to developers, but have new or altered definitions in the IIS environment. If you are looking for a term that is not defined here, please see the glossary in the IIS User Documentation that comes with IIS Manager, or see the glossary in the IIS Resource Kit.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A
ABO
abstract class
In Windows Management Instrumentation (WMI), a class from which you cannot create an instance because it does not have a full implementation. An abstract class serves as a base class from which other classes can inherit properties and methods. Also see concrete class.
Active Directory Service Interfaces (ADSI)
A directory service model and a set of Component Object Model (COM) interfaces. ADSI enables Windows applications and Active Directory clients to access several network directory services, including Active Directory. ADSI is supplied as a software development kit (SDK). Also see Windows Management Instrumentation (WMI).
Active Server Pages (ASP)
A Web-oriented technology developed by Microsoft that is designed to enable server-side (as opposed to client-side) scripting. Active Server Pages are text files that can contain not only text and HTML tags as in standard Web documents, but also commands written in a scripting language (such as VBScript or JavaScript), that can be carried out on the server.
Admin Base Objects (ABO)
A distributed COM (DCOM) object that implements the IMSAdminBase interface methods that enable an application to manipulate IIS metabase. ABO is often confused with admin objects.
admin objects
Used with ADSI and WMI. There exists an admin object for each type of configuration entity, for example, the IIsWebService admin object represents the Web service for the purposes of configuration, and the IIsWebVirtualDir admin object represents any virtual directory. Individual virtual directories are differentiated by their Location property, for example, /LM/WSVC/1/Root/vdir1 and /LM/WSVC/1/Root/vdir2 are both defined as IIsWebVirtualDir objects, but they are different virtual directories defined at different nodes in the metabase. Admin objects are often confused with Admin Base Objects (ABO).
ADSI
application isolation
application pool
ASP

B

C
CGI
CIM
Common Gateway Interface (CGI)
An interface that is used by executable files that handle specific requests. An IIS server can execute a CGI, exchange data with the client via stdin and stdout, and get IIS server variables through environment variables.
Common Information Model (CIM)
An industry standard technique to represent systems, applications, networks, devices, and other managed components in an enterprise environment. Used by Windows Management Instrumentation (WMI) to access management information in an enterprise environment.
compatibility mode
Component Object Model (COM)
The object-oriented programming model that defines how objects interact within a single application or between applications. In COM, client software accesses an object through a pointer to an interface on the object.
concrete class
In Windows Management Instrumentation (WMI), a class from which you can create an instance because it has a full implementation. See also abstract class.
to top

D
Distributed COM (DCOM)
A wire protocol that enables software components to communicate directly over a network.
to top

E

F

G

H

I
IIS 5.0 isolation mode
in-process
inheritable property
A metabase property in a parent node that trickles down to child nodes without having to be specifically set at the child nodes. Specifically setting the same property at a child node over-writes the inherited value. Also see inherited property.
inherited property
A metabase property in a child node that was inherited from its parent node. Inherited properties do not show up as being specifically set at the child node. Specifically setting the property at a child node over-writes the inherited value. Also see inheritable property.
INP
Internet Server API (ISAPI)
An interface that resides on an IIS server for the purpose of initiating software services that are tuned for the Windows operating system. ISAPI is an API for developing extensions to Internet Information Services (IIS) and other Hypertext Transfer Protocol (HTTP) services that support the ISAPI interface. When an ISAPI DLL is used to generate content to display to a client, it executes faster than an ASP page (which is not compiled code) or a COM component. However, since ISAPI DLLs can only be written in C/C++, they are more difficult to develop.
ISAPI
ISAPI extension
An ISAPI DLL that handles a specific incoming request to the IIS server. ASP.dll and ASPNET_ISAPI.dll are examples of Microsoft®-provided ISAPI extensions. Extensions are loaded when first needed and kept in memory until the host process shuts down. Also known as ISAPIs.
ISAPI filter
An ISAPI DLL registered with Internet Information Services (IIS) that modifies the behaviour of the server. URLScan.dll is an example of a Microsoft®-provided ISAPI filter. Filters are loaded when the worker process starts and unloaded when the worker process shuts down. Also known as filters.
to top

J

K
key
In the IIS metabase: See node as defined for the IIS metabase.
In the Windows registry: A node in the registry. A key can contain subkeys and entries, for example, Environment is a key of HKEY_CURRENT_USER.
In IP security (IPSec): A value used in combination with an algorithm to encrypt or decrypt data. Key settings for IPSec are configurable to provide greater security.
to top

L
location
See node as defined for the IIS metabase.
low isolation

M
medium isolation
Metabase
A hierarchical store of configuration information and schema that is used to configure IIS. The metabase performs some of the same functions as the system registry, but it uses less disk space.
IIS 6.0: In physical terms, the metabase is a combination of the MetaBase.xml and MBSchema.xml files. IIS works from an in-memory metabase that periodically generates the physical files.
IIS 5.1 and earlier: In physical terms, the metabase is a binary-formatted file.
Also see node.
to top

N
node
In the IIS metabase: A hierarchical container in the IIS metabase. Each node allows a specific set of properties to be configured at that location or path. For example, at the Web service node, identified by the IIsWebService admin object at the /LM/WSVC path in the metabase, certain properties like AppRoot can be set which affect the IIS Web service. A node is a child of another node if its path includes the path of the parent, for example, /LM/WSVC/1 is a child node of /LM/WSVC. A node in the metabase is also referred to as a key.
to top

O

P
path
In the IIS metabase: See node.
POOL
pooled-process

Q

R

S
Schema
A representation of the structure of something. Classes in Visual Basic and C++ can be said to be schemas of objects, and objects are instances of classes. In IIS, the metabase schema represents the structure of the metabase configuration file.
to top

T

U
Uniform Resource Locator (URL)
A naming convention that uniquely identifies the location of a computer, directory, or file on the Internet. A URL also specifies the appropriate Internet protocol, such as Hypertext Transfer Protocol (HTTP) or File Transfer Protocol (FTP). An example of a URL is http://www.microsoft.com.
URL
URL mapping

V
Vdir
virtual directory
A directory name, used in a URL (or Web) address, that corresponds to a physical directory on the server. In the URL http://www.microsoft.com/widgets, widgets is the virtual directory which is mapped to a physical directory on one of the http://www.microsoft.com servers. Sometimes called a URL mapping or a vdir.
virtual server
In Windows: In a server cluster, a collection of services that appear to clients as a physical Windows-based server but are not associated with a specific server. A virtual server is typically a resource group that contains all of the resources needed to run a particular application and that can be failed over like any other resource group. All virtual servers must include a Network Name resource and an IP Address resource.
In IIS: See Web site.
to top

W
WAM
Web Application Manager (WAM)
Web site
A collection of content files or applications that can be viewed in an Internet browser (like Internet Explorer) when you type in a Uniform Resource Locator (URL) like http://www.microsoft.com. A Web site can contain many virtual directories. Also called a virtual server.
Web service extension restriction list
A list of ISAPIs and CGIs used by applications on the Web server, including their location, descriptive information, and a flag for determining whether the Web service extension is enabled or disabled.
IIS 5.0 and earlier: This feature is not available.
Windows Management Instrumentation (WMI)
The Microsoft implementation of Web-Based Enterprise Management (WBEM), which is an industry-wide standard technology for accessing management information about systems in an enterprise environment. WMI uses the Common Information Model (CIM) industry standard to represent managed components in a system. A system developer can develop a WMI interface that allows programmatic access to a system, so that users can write command-line administration scripts and tools. Also see Active Directory Service Interfaces (ADSI).
WMI
worker process
worker process isolation mode
WSERL

X

Y

Z