| |
- B. Jeram, G. Chiozzi, R.J. Tobar
ESO, Garching bei Muenchen, Germany
- R. Amestica
NRAO, Charlottesville, USA
- M. Watanabe
NAOJ, Tokyo, Japan
|
|
| |
Bulk Data(BD) is a service in the ALMA Common Software to transfer a high amount of astronomical data from many-to-one, and one-to-many computers. Its main application is the Correlator SW (processes raw lags from the Correlator HW into science visibilities). The Correlator retrieves data from antennas on up to 32 computers. Data is forwarded to a master computer and combined to be sent to consumers. The throughput requirement both to/from the master is 64 MBytes/sec, differently distributed based on observing conditions. Requirements for robustness make the application very challenging. The first implementation, based on the CORBA A/V Streaming service, showed weaknesses. We therefore decided to replace it, even if we were approaching start of operations, making provision for careful testing. We have chosen as core technology DDS (Data Distribution Service), being a well supported standard, widespread in similar applications. We have evaluated mainstream implementations, with emphasis on performance, robustness and error handling. We have successfully deployed the new BD, making it easy switching between old and new for testing purposes. We discuss challenges and lessons learned.
|
|
