taglinefilesource code
HD_ERROR150drivers/block/hd.chd_error = inb(HD_ERROR);
HD_ERROR381drivers/block/hd.celse if ((hd_error = inb(HD_ERROR)) != 1)
HD_ERROR22include/linux/hdreg.h#define HD_FEATURE HD_ERROR  /* same io address, read=error, write=feature */