CAC_GET2
_lto4b( CAC_GET2(dinfo->ncylinders) * CAC_GET1(dinfo->nheads) *
size = CAC_GET2(dinfo->ncylinders) *
blks = CAC_GET2(dinfo.ncylinders) * CAC_GET1(dinfo.nheads) *
bv->bv_size = (off_t)blks * CAC_GET2(dinfo.secsize);