Giovanna (in absentia), Enrico, Roland: updates at EHN1

• the FLX-711 card has been connected to the patch panel
• plan is to connect the WIB to the patch panel tomorrow and test the links
• then, run the actual DAQ
  • should be able to use WIB internal generation

Other updates: Overlay class implementation by Milo is now working

• implementation w/o compression
• to be communicated to Antonino and tested with WIB data soon

Schedule:

• 5 WIBs arriving soon; to be used for Cold-box testing
  • expect to be able to hook up FELIX to these, even if only for shorter periods of time
  • Eric: does this use the same firmware? Dan: yes, just need JTAG to configure for FELIX instead of RCE
• Frank: order for 3 Mellanox (dual 100 GB/s) cards and 2 corresponding 5m cables going out ~ now; can hopefully be at CERN in ~ 1.5 weeks
• Roland: two separate BoardReader PCs (Dell PowerEdge R740; 14 cores; high-end Xeon Silver or low-end Xeon Gold) to be ordered
  • expect these to be at CERN in a few weeks
  • possibility to use QAT (and not under non-disclosure agreement anymore)

Planning (near- and mid-term):

• start running without compression
• then use QAT for compression
  • this uses deflate (see https://en.wikipedia.org/wiki/DEFLATE), which combines LZ77 and Huffman coding
  • Frank: what compression factor did this yield in the past? Roland: a factor of ~ 2
    • clearly well below that of Milo's s/w based compression, but on the other hand a lot better than not compressing at all
  • Frank: this shouldn't compress artdaq Fragment headers? Roland: it won't
  • Milo: a lot depends on the ordering of the data. Roland: indeed, the above factor of 2 is w/o any re-ordering.
  • we can try re-ordering the data in s/w and then using QAT for the compression
• other compression schemes can be looked into later
• related (potential) Overlay issues:
  • idea is to start using a separate FELIX fragment type, but to converge to the more generic TPC fragment type
  • distinguishing between different compression schemes (and between FELIX and RCE) will still be possible as the relevant metadata is not limited to the fragment type

Next meeting: tentatively planned for October 18 (we can at least discuss further the progress at EHN1)