VDC_Write

This command must always be supported. It transfers size bytes from the buffer to the device. The number of bytes successfully transferred must be returned. Position is defined only if VDF_RandomAccess is set.

During BACKUP operations, the client may cache the output data stream. Microsoft® SQL Server™ issues the Flush command when it needs to be sure that data is actually stored in a durable fashion.

The following is a list of error codes and their descriptions:

• ERROR_DISK_FULL. This indicates that the device is not capable of storing more information. SQL Server responds to this code by aborting the BACKUP operation.
  
  
• ERROR_EOM_OVERFLOW. This indicates that the device is not capable of storing more information. SQL Server responds to this code by aborting the BACKUP operation.
  
  
• ERROR_END_OF_MEDIA. This indicates that the device has reached the end of media warning. For more information, see End of Media and Unexpected Filemarks.