get_harddrives
if (biosdev >= 0x80 + get_harddrives()) {
*biosdev = 0x80 + get_harddrives() + unit;
} else if (biosdev >= 0x80 + get_harddrives()) {
*unit -= get_harddrives();
if (d->dev >= 0x80 + get_harddrives()) {
nhd = get_harddrives();
int get_harddrives(void);