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Annotation of researchv9/sys/h/dkbad.h, revision 1.1

1.1     ! root        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 126 bad sectors are supported.
        !            15:  * The position of the bad sector in the bad sector table
        !            16:  * determines which replacement sector it corresponds to.
        !            17:  *
        !            18:  * The bad sector information and replacement sectors
        !            19:  * are conventionally only accessible through the
        !            20:  * 'c' file system partition of the disk.  If that
        !            21:  * partition is used for a file system, the user is
        !            22:  * responsible for making sure that it does not overlap
        !            23:  * the bad sector information or any replacement sector.s
        !            24:  */
        !            25: 
        !            26: struct dkbad {
        !            27:        long    bt_csn;                 /* cartridge serial number */
        !            28:        u_short bt_mbz;                 /* unused; should be 0 */
        !            29:        u_short bt_flag;                /* -1 => alignment cartridge */
        !            30:        struct bt_bad {
        !            31:                u_short bt_cyl;         /* cylinder number of bad sector */
        !            32:                u_short bt_trksec;      /* track and sector number */
        !            33:        } bt_bad[126];
        !            34: };
        !            35: 
        !            36: #define        ECC     0
        !            37: #define        SSE     1
        !            38: #define        BSE     2
        !            39: #define        CONT    3

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