dkbad.h

Macros

BSE               X
CONT              X
ECC               X
MAXBAD            X
SSE               X

struct's

bt_b              X
dkbad             X

   1: /*
   2:  * Definitions needed to perform bad sector
   3:  * revectoring ala DEC STD 144.
   4:  *
   5:  * The bad sector information is located in the
   6:  * first 5 even numbered sectors of the last
   7:  * track of the disk pack.  There are five
   8:  * identical copies of the information, described
   9:  * by the dkbad structure.
  10:  *
  11:  * Replacement sectors are allocated starting with
  12:  * the first sector before the bad sector information
  13:  * and working backwards towards the beginning of
  14:  * the disk.  A maximum of MAXBAD bad sectors are supported
  15:  * per pack; MAXBAD may be redefined as conditions require,
  16:  * but may be 126 at most.  It is small to save on the kernel
  17:  * memory required to hold these.
  18:  * The position of the bad sector in the bad sector table
  19:  * determines which replacement sector it corresponds to.
  20:  * Bad sectors in excess of MAXBAD will not be replaced
  21:  * automatically, but the bad-sector file on disk will be correct.
  22:  *
  23:  * The bad sector information and replacement sectors
  24:  * are conventionally only accessible through the
  25:  * 'h' file system partition of the disk.  If that
  26:  * partition is used for a file system, the user is
  27:  * responsible for making sure that it does not overlap
  28:  * the bad sector information or any replacement sectors.
  29:  */
  30: 
  31: #ifdef  BADSECT
  32: 
  33: #define MAXBAD  8
  34: 
  35: struct dkbad {
  36:     long    bt_csn;         /* cartridge serial number */
  37:     u_short bt_mbz;         /* unused; should be 0 */
  38:     u_short bt_flag;        /* -1 => alignment cartridge */
  39:     struct bt_b {
  40:         u_short bt_cyl;     /* cylinder number of bad sector */
  41:         u_short bt_trksec;  /* track and sector number */
  42:     } bt_bad[MAXBAD];
  43: };
  44: 
  45: #if MAXBAD > 126
  46: ERROR!
  47: #endif
  48: #endif	BADSECT
  49: 
  50: #define ECC 0
  51: #define SSE 1
  52: #define BSE 2
  53: #define CONT    3