set_ch_t
set_ch_t(&address,
set_ch_t(&geo, i / trk_per_cyl, i % trk_per_cyl);
set_ch_t(&data->beg_ext, begcyl, beghead);
set_ch_t(&data->end_ext, endcyl, endhead);
set_ch_t(&ras_range->beg_ext, beg_cyl, beg_head);
set_ch_t(&ras_range->end_ext, end_cyl, end_head);
set_ch_t(&dedata->beg_ext, begcyl, beghead);
set_ch_t(&dedata->end_ext, endcyl, endhead);
set_ch_t(&lredata->seek_addr, begcyl, beghead);
set_ch_t(&data->seek_addr,
set_ch_t(&data->seek_addr,