All right, you guys! I've been watching this conversation fly by for some weeks now, and I have one burning question to ask: What the #%$@ does the MARK instruction do??!? Gary Ansok GEACC022%TIMEVX%CITHEX @ LBL-G.ARPA GEA @ CALTECH.BITNET ...ucbvax!cithep!timevx#geacc022 "All the world loves a straight man."