[MS-VDS]: Virtual Disk Service (VDS) Protocol Specification

3 Protocol DetailsThe following sections specify details of the VDS Remote Protocol, including abstract data models,interface method syntax, and message processing rules.3.1 InterfacesAll VDS interfaces that are listed in this section inherit the IUnknown interface. For all VDSinterfaces, method opnum field values start with 3; opnum values 0, 1, and 2 represent theIUnknown::QueryInterface, IUnknown::AddRef, and IUnknown::Release methods, respectively. Formore information, see [MS-DCOM] section 3.1.1.5.8.The interfaces in this section are listed in the following order:•Generic object interfaces: Enumeration Object Interfaces (section 3.1.1) through AsynchronousOperation Object Interfaces (section 3.1.3).•Service object interfaces: Service Object Interfaces (section 3.1.5) through HBA Port ObjectInterfaces (section 3.1.6).•Provider interfaces: Provider Object Interfaces (section 3.1.9).•Pack interfaces: Pack Object Interfaces (section 3.1.11).•Disk interfaces: Disk Object Interfaces (section 3.1.12).•Volume interfaces: Volume Object Interfaces (section 3.1.13).•Volume plex interfaces: Volume Plex Object Interfaces (section 3.1.14).This order reflects the logical hierarchy of objects in VDS. For more information, see section 3.4.1.To retrieve the interfaces of a particular object, call the QueryInterface method on the DCOMIUnknown interfaces of the object. For more information, see [MS-DCOM] section 3.1.1.5.8.Unless otherwise specified, all methods MUST return zero or a nonerror HRESULT (as specified in[MS-ERREF]) on success, or an implementation-specific nonzero error code on failure (see section2.2.3 for more information on the HRESULT values predefined by the Virtual Disk Service RemoteProtocol).Unless otherwise specified, client implementations of this protocol MUST NOT take any action on anerror code, but rather, return the error to the invoking application.The set of required and optional interfaces is organized into five groups. Group 1 is the required setof interfaces. Groups 2 through 5 are optional sets of interfaces.If one interface from an optional group is implemented, all interfaces in that group MUST beimplemented.The groups form an additive set: Group 1 is required. If one interface from group 2 is implemented,all interfaces in group 1 and group 2 are implemented. If one interface from group 3 isimplemented, that implies that all interfaces in groups 1, 2, and 3 are implemented.Group 1[MS-VDS] — v20110610Virtual Disk Service (VDS) Protocol SpecificationCopyright © 2011 Microsoft Corporation.Release: Friday, June 10, 2011116 / 360