mmioIdentifyStorageSystem processes the MMIO internal I/O procedure list to determine if the file name specified is of type MMIO_IOPROC_STORAGESYSTEM. If it is, an MMIOM_IDENTIFYFILE message is sent to the I/O procedure to see if it can identify the data object. The pfccStorageSystem parameter contains the FOURCC code of the I/O procedure that successfully identified the data object.