struct sgbuf { /* structure for 'getstat()' and 'setstat()' */
   char sg_class,       /* device class */

/* The following are for an SCF type device. See below for
 * structure member definitions for an RBF device.
 */
        sg_case,        /* 0 = upper and lower cases, 1 = upper case only */
        sg_backsp,      /* 0 = BSE, 1 = BSE-SP-BSE */
        sg_delete,      /* delete sequence */
        sg_echo,        /* 0 = no echo */
        sg_alf,         /* 0 = no auto line feed */
        sg_nulls,       /* end of line null count */
        sg_pause,       /* 0 = no end of page pause */
        sg_page,        /* lines per page */
        sg_bspch,       /* backspace character */
        sg_dlnch,       /* delete line character */
        sg_eorch,       /* end of record character */
        sg_eofch,       /* end of file character */
        sg_rlnch,       /* reprint line character */
        sg_dulnch,      /* duplicate last line character */
        sg_psch,        /* pause character */
        sg_kbich,       /* keyboard interrupt character */
        sg_kbach,       /* keyboard abort character */
        sg_bsech,       /* backspace echo character */
        sg_bellch,      /* line overflow character (bell) */
        sg_parity,      /* device initialisation (parity) */
        sg_baud;        /* baud rate */
   int  sg_d2p,         /* offset to second device name string */
        sg_stn;         /* offset to status routine name */
   char sg_err;         /* most recent error status */
   char sg_spare[5];    /* spare bytes - necessary for correct sizing */
};

/* the following is a structure definition to set the names, types
 * and offsets of structure members which are applicable to an RBF
 * type device file.
 */
struct {
   char sg_class,       /* device class - repeated from above */
        sg_drive,       /* drive number */
        sg_step,        /* step rate */
        sg_dtype,       /* device type */
        sg_dense;       /* density capability */
   int  sg_cyls;        /* number of cylinders (tracks) */
   char sg_sides,       /* number of sides */
        sg_verify;      /* 0 = verify on writes */
   int  sg_spt,         /* default sectors per track */
        sg_spt0;        /* ditto track 0 */
   char sg_intlv,       /* sector interleave factor */
        sg_salloc,      /* segment allocation size */
        sg_att,         /* file attributes */
        sg_fdpsn[3],    /* file descriptor PSN */
        sg_dipsn[3];    /* file's directory PSN */
   long sg_dirptr;      /* directory entry pointer */
   int  sg_dvt;         /* address of device table entry */
};