Returns the BIOS disk parameters in the following structure:
struct hd_geometry {
unsigned char heads;
unsigned char sectors;
unsigned short cylinders;
unsigned long start;
};
A pointer to this structure is passed as the
ioctl(2) parameter.
The information returned in the parameter is the disk geometry of the drive
"as understood by DOS!" This geometry is
not the physical geometry of the drive. It is used when constructing the
drive's partition table, however, and is needed for convenient operation
of
fdisk(1) , efdisk(1) , and
lilo(1) . If the geometry information is not available, zero will be returned for all
of the parameters.