1. 05/08/09

2. FPGA Spectrometer for the GBT - Risks
05/08/09
FPGA Spectrometer for the GBT - Risks
NRAO and U.C. Berkeley Joint Conceptual Design Review
January 31, 2011

3. R&D Items
Remember that as an NSF ATI project, there is significant R&D associated with the development effort!
High-speed sampling
3 GS/s ADCs and processing
High-density logic packing
Extremely full FPGAs
Heterogeneous Computing
Use of GPUs for mainstream spectroscopic signal processing
These R&D items will provide capability to the entire CASPER community.

4. Project Risks & Mitigation
05/08/09
Project Risks & Mitigation
Project risks are largely mitigated because -
Well established science case
Detailed, prioritized specifications
Teams have extensive experience in similar systems
Three GUPPI-style systems built by NRAO
Fly's Eye Transient 42-spectrometer (ATA)
PAPER correlator
ATA correlators and beamformers
Proven technology
Broad use in astronomy and other scientific systems
Large industry group
Open architecture, open source (mostly) 4

5. Identified Risks - Performance
Specification is incomplete or incorrect
Mitigation: Multiple internal reviews with entire NRAO Science Staff and overall review in the Conceptual Design Review and a Critical Design Review
System performance is insufficient to meet speed requirements of the science case
Mitigation: Identified as a risk early on, much of the early work focused on characterizing the performance of the system components and system architecture. Calculated system benchmarks to date, show the system will meet requirements

6. Identified Risks – Development
Roach board development – Availability of Roach 2 boards for production spectrometer.
Mitigation: Three GUPPI systems have been deployed on Roach 1 boards by the NRAO/Berkeley team. The spectrometer is being developed and benchmarked so that if the performance, reliability, or availability of the Roach 2 becomes a problem, a fully operational spectrometer can be built using Roach 1 boards.
Hardware Capabilities.
Mitigation: Specific Berkeley resources have focused on FPGA issues and is nearing completion of work to verify the necessary speeds for various spectrometer modes are supported in the design.
I/O Speeds.
Mitigation: As above, specific resources at Berkeley are dedicated to optimizing I/O speeds on-board the ROACH board and throughout the system. A dedicated system integration resource joins the Berkeley team in March

7. Identified Risks – Outside Reqs.
What requirements are ‘embedded’ in the Virtual Astronomy Observatory (VAO)? Would these affect the GB Spectrometer archiving plans and policies?
Mitigation: Since the timeline of the spectrometer development grant require these decisions to be made before VAO requirements are finalized, no assurance of compliance with VAO requirements is guaranteed.

8. Identified Risks – Staffing
Will resources be available for the duration of the spectrometer project?
Mitigation: While drastic budgetary actions in future years could have a devastating effect on the development and deployment. All members of the NRAO staff are full-time staff with varying, but generally long tenure with NRAO. The Berkeley team is comprised of a combination of staff positions and students, mostly post-graduate and post-doc positions with well defined project tenure.

9. Early Science Demands
There is risk that early science demands will drive schedules and design decisions in ways that are not necessarily best for the long-term operations (e.g. Roach1 v. Roach2 decision).
Mitigation: The project will monitor science requests and commitments along with NRAO management to assess the effect of taking on any aggressive science cases before the designs and implementations are ready.

10. Review Comments Rich Lacasse Data Rate is huge!
Design Verification, Test, systems integration?
Real-time monitoring for operators and engineers?
What will be done with the old spectrometer?