NRBUF
mem += NRBUF * sizeof(struct mds);
for (i = 0; i < NRBUF; i++) {
if (++sc->sc_next_rd >= NRBUF)
(QW_ALLOC(sizeof(struct buffdesc) * NRBUF) + addoff);
for (i = 0; i < NRBUF; i++) {
sizeof(struct buffdesc) * NRBUF);
if (++next_rdesc >= NRBUF)