Description

When a client creates the virtual device set, it specifies inputs to the configuration to be used by initializing a VDConfig structure. When the server opens the virtual device set, it examines these inputs and the BACKUP or RESTORE command inputs, such as BLOCKSIZE, MAXTRANSFERSIZE, and BUFFERCOUNT. This information helps determine the actual configuration used.

After the virtual device set has been configured by the server, the client can obtain the configuration by using the GetConfiguration function.

If either the server or the client is unable to work with the selected configuration, SignalAbort can be used to terminate the connection.

The VDI supports an optional buffer prefix zone for the convenience of the client.

Note   The start of the data zone is used for alignment purposes. The prefix zone is placed immediately prior to the start of the data.

The configuration supports a serverTimeOut. The client may choose a time-out interval to be used by the server. If the server's completion agent waits longer than two time-out intervals with requests pending and no request completing, the operation is aborted automatically.

This feature is intended to be a debugging aid. Applications may need to implement their own time-out logic to reliably handle issues such as mount requests for removable media.