DART (Data Available in Real Time)
The DART (Data Available in Real Time) provides an network-accessible structured filesystem to support real-time access to current and recent timeseries data from all networks, stations, and channels. All real-time timeseries data streams delivered to the NCEDC are placed in MiniSEED files in a Web-accessible directory structure. The DART currently contains the most recent 40 days of data. The DART waveforms can be accessed by users from Web browsers or command-line programs such as wget, or through NCEDC Web Services or SWC.
We use the IRIS ringserver software as the primary method for delivering real-time data to the DART. The ringsever packages implement an object ring buffer (ORB) and server which provides a reliable storage ring buffer and an interface for client programs to read, write, and query the orbserver. Clients running at the NCEDC computer connect to remote servers at the BSL, USGS/Menlo Park, and UNAVCO, retrieve the MiniSEED timeseries data records, and write them to daily channel files in the NCEDC DART. Strain data from the EarthScope PBO network are delivered to the NCEDC using SeedLink and are inserted into the DART using a similar SeedLink client program.
The NCEDC developed an automated data archiving system to archive data from the DART on a daily basis. It allows us to specify which stations should be automatically archived, and which stations should be handled by the NCEDC's Quality Control program calqc. The majority of non-BSL data channels are currently archived automatically from the DART.