The fx-CG20 uses a FAT16.
The directory is very similar to the PC DOS directory structure.
The directory does not reside at a fixed position.
A directory entry consists of 32 bytes:
Bytes 0-7
Filename
Bytes 8-10
Filename extension
Byte 11
File's attribute
0x10: directory
0x0F: unknown
0x20: file (archive bit; set on whenever a file has been written to and closed)
Bytes 12-21
Unknown, yet.
Bytes 22-23
Formerly the file time
Bytes 24-25
Formerly the file date.
Bytes 26-27
The starting cluster number (little endian)
Bytes 28-31
File size (little endian)
(15.06.2011 11:57:52)