Device Parameter Block data structure.

typedef struct _DEVICEPARAMETERBLOCK {
  USHORT     reserved1;         /*  Reserved. */
  USHORT     cCylinders;        /*  Number of Cylinders on the physical drive. */
  USHORT     cHeads;            /*  Number of Heads on the physical drive. */
  USHORT     cSectorsPerTrack;  /*  Number of Sectors per track on the physical drive. */
  USHORT     reserved2;         /*  Reserved. */
  USHORT     reserved3;         /*  Reserved. */
  USHORT     reserved4;         /*  Reserved. */
  USHORT     reserved5;         /*  Reserved. */
} DEVICEPARAMETERBLOCK;

typedef   DEVICEPARAMETERBLOCK   * PDEVICEPARAMETERBLOCK ;