MADIS runs operationally in real-time in the National Weather Service (NWS) with a distributed architecture consisting of ingest and distribution services at the Telecommunications Operations Center (TOC) with processing performed at the National Centers for Environmental Prediction (NCEP) Central Operations (NCO). MADIS also runs quasi-operationally in a research test environment at ESRL/GSD, where new advances are developed and tested prior to being put into operations. The ESRL/GSD system also has an archive of saved real-time data, and serves as the backup to the operational system.