This is not a dedicated emulator format, but instead, a disk image created by unknown software. As such, the format description below is entirely reverse engineered.
The file itself only contains a 256 byte header, followed by C/H/S data. There have been two types of disk geometry observed in the wild: Disk Format DWORD: ------------------ 01 - HDM - 2 heads, 77 cylinders, 8 sectors/track, 1024 bytes/sector = 1,261,568 bytes of C/H/S data 02 - 2 heads, 77 cylinders, 26 sectors/track, 256 bytes/sector = 1,025,024 bytes of C/H/S data FIM Header -------------- Offset 0x00 - 0x03 byte "Magic Word" - FIVEC only uses the first four bytes to identify file: 0x01, 0x00, 0x00, 0x00 Offset 0x04 - 0x07 byte - Disk Format DWORD, used to identify disk geometry above Offset 0x08 - 0x0B byte - Track count, DWORD Offset 0x100+ - Raw data in C/H/S format
