One of the following pl_fd_status_codes, also affects fd.laststatus:
0- PL_FD_STATUS_OK: Completed successfully.
1- PL_FD_STATUS_FAIL : Physical flash memory failure (fatal).
2- PL_FD_STATUS_CHECKSUM_ERR: Checksum error has been detected in one of the disk sectors (fatal).
3- PL_FD_STATUS_FORMAT_ERR: Disk formatting error has been detected (fatal).
8- PL_FD_STATUS_NOT_READY: The disk is not mounted.
9- PL_FD_STATUS_NOT_FOUND: File not found.
11- PL_FD_STATUS_ALREADY_OPENED: This file is already opened "on" some other file number.