TRM_USR_DISCENB
pDCB->tinfo.disc_tag |= TRM_USR_DISCENB ;
pDCB->tinfo.disc_tag &= ~(TRM_USR_DISCENB);
if (pDCB->tinfo.disc_tag & TRM_USR_DISCENB)
|= TRM_USR_DISCENB;
~TRM_USR_DISCENB;