[Jecci]

This Disk is not formatted,no initializtion.So can't use GetDiskFreeSpace function.

I use DeviceIoControl function for send IOCTL_DISK_GET_DRIVE_GEOMETRY command to get Disk geometry,but why the returns Cylinders is 36474 ?

I gets my disk geometry:
Cylinders 36474 (LowPart 36474,HighPart 0)
MediaType FixedMedia
TracksPerCylinder 255
SectorsPerTrack 63
BytesPerSector 512

Please help,Thanks in advance.