typedef struct {
    char num_sides;		/* off 0 */
    char num_cylinders;		/* off 1 */
    char sectors_per_track;	/* off 2 */
    char gap3;			/* off 3 */
    char skew_flag;		/* off 4 */
    char data_length;		/* off 5 */
    short int bytes_per_sector;	/* off 6 */
    unsigned short int motor_delay; /* off 8 */
    char head_load;		/* off 10 */
    char step_rate;		/* off 11 */
    char track_format;		/* off 12 */
    char density;		/* off 13 */
    char retry;			/* off 14 */
    char ignore_errors;		/* off 15 */
    char soft_error;		/* off 16 */
    char double_step;		/* off 17 */
    char unused[14];		/* off 18 to 31 */
    } CONFIGBLK;