The trend towards powerful workstations and high-speednetworks has enabled applications to communicate andmanipulate digital audio and video. These are continuousmedia and differ from discrete media such as text andgraphics in that they have stringent delay and bandwidthrequirements. Neither the mechanisms used to transportordinary data over networks nor present communicationprotocols are sufficient to communicate continuous media.Special operating system support must also be provided tomeet the requirements of both discrete and continuous mediain future multimedia applications.This volume contains the proceedings of the SecondInternational Workshop on Network and Operating SystemSupport for Digital Audio and Video, held in cooperationwith ACM SIGCOMM and SIGOPSat the IBM European NetworkingCenter in Heidelberg, Germany, in November 1991. The volumecontains 33 selected papers together with summaries of theworkshop sessions compiled by the session chairmen.