Minutes of Online Meeting
21st October, 1998

Present:

Jean-Pierre Duffey, Phlippe Gras, Frank Harris, Beat Jost, Hans Muller, Jose Toledo, Markus Tujula

Agenda:

  1. First Experiences with Myrinet                 Markus Tujula
  2. Discussion on DAQ Workshop               All
  3. AOB

1) First Experiences with Myrinet (Slides 1,2,3)

Markus Presented the work he has been doing with Myrinet so far.

One result of his work is a graph on the raw Myrinet performance Between two LANai processors. It shows that the typical behavior of a constant overhead plus a limited transfer speed.

Next step step is a piece of code to do the fragment asssembly in the LANai processor and send only complete events to the PC.

2) Discussion on DAQ Workshop

Beat raised the question of whether we should really organize a DAQ workshop as announced in the last LHCb week.

While there was agreement that such a workshop might be useful provided that there is a quorum of participation from the subdetectors and there is a clear objective, there was some disagreement about these objectives. Experience has shown so far that there is fairly little interest from the subdetectors in DAQ matters up to now. Whereas the online 'group' has iformed the collaboration quite extensively about their projects, we don't know anything so far about the intentions of the subdetectors vis-a-vis the DAQ. It was therefore felt to be useful to also include presentations of the subdetector groups on this subject. The disagreement in the discussion basically centered on the expectations we should have on the sub-detector presentations mainly in the 'Off-Detector-Electronics', i.e. whether it should be of concern of the DAQ group how the ODE is implemented and whether there should be a common approach to it. It was agreed that the workshop should have two parts: one part in which the subdetector groups present their views of the DAQ (after L0-Yes) and one part in which the online group presents their ideas/projects. Possible items could be

It was agreed that Beat would draft a mail to the SD coordinators and circulate it for comments before sending it off.

Possible dates could be either before or immediately after the next LHCb week (30/11-4/12) or otherwise sometime beginning of 1999.

3) AOB

There was no other business.

 

Minutes Prepared by Beat Jost