OWG Meeting 25-Apr-2012

Agenda

• Announcements
  • Run-around at 3pm
• Review of minutes from 11-Apr-2012 meeting
• Mini-Hbook - Sergey B
• Hall D Component Inventory Database
• Counting house - Hovanes
• TDR - Dave L, Elliott
• 12GeV planning lines - David, Hovanes, Elliott
• Elog and Accelerator division projects - Graham
• DAQ group - Bryan, Dave A, Graham
  • CODA3, EVIO, ECS/CSS, raw event file, disentangler, readout list
• EPICS - Hovanes, Vanik
  • transfer some projects to Accelerator Div.
• Controls - Elliott
  • UPS strategy
  • Solenoid Controls Redesign, PXI order, FMEA
• Electronics, trigger and DAQ status reports - Chris, Alex, Dave, Fernando, Ben, Ed, William, Bryan
• Mantis Task Tracker
• Midas Elog

• Calibration/Alignment issues?
• Computer system manager

Time/Location

1:30 PM Wed 25-Apr-2012 CC F326

Next Meeting

1:30 PM Wed 9-May-2012 CC F326

Minutes

Present: Elliott W, Simon T, Bryan M, Sergey B, Hovanes E, Beni Z, Eugene C.

This was a short meeting due to the annual JLab Run-a-Round at 3pm. We broke at 2:30pm. Most of the time was taken up hearing from Sergey Boiarinov about the mini-Hbook system he implemented for the CLAS online. After that we had cursory reports about a few topics.

mini-Hbook

Sergey created this facility in 2004 to gather information about primary and secondary readout list execution times in the ROCS. Histograms are created and filled in the ROCs, then transmitted to display programs via the event stream (ET system) every 100k events (every few secs or so). The display programs use config files to tell them which histograms to extract from the data stream, how to display them, whether and how to sum them, etc. The origianal version worked well and he expanded its use somewhat over the years.

Only a few Hbook-like API calls are implemented, just the ones needed to book and fill 1-D and 2-D histograms. The display programs accept the mini-Hbook histograms and convert them to real Root histograms, then use the full power of Root to display and analyze them. In this way the memory/processing footprint in the ROC is minimized, with no dependence on large libraries, version incompatibilities, etc. He strongly recommends against using Root itself in the front-ends. Despite the large amount of memory available in ROCs these days he still prefers mini-Hbook to Root because it vastly simplifies management of the ROCs.

Currently the histograms are serialized to BOS format prior to injection into the CLAS data stream. For CLAS12 they will be converted to EVIO format. Once serialized the histograms can be transmitted in a number of ways, including via the DAQ cMsg system. Note that an ongoing debate concerns whether to transfer meta-data, such as histograms, in-band via the ET system or out-of-band via another system. Probably it's must a matter of taste. Sergey prefers in-band but recognizes that other mechanisms should work just as well.

Serialization is optimized to send binned data or sparse data, whichever is most efficient. Many large histograms have sparse data so this is an important optimization. Underflows, overflows and some other statistical data are accumulated.

The CLAS12 offline may use this facility in their CLARA environment. Here a large amount of data gets transferred over the network during event processing, and minimizing the memory footprint of histogram data may be critical.

Sergey's library is currently only available in C, but it is possible to wrap the C library via SWIG and thus create API's in Python, Java, etc.

Sergey and Elliott will place the mini-Hbook library in the 12GeV repository so Hall D can test it.

On a side note, the HPS experiment in Hall B currently uses multiple crates full of FADC's, block readout, the new trigger system, etc. Sergey disentangles events in the secondary readout list. On a modern quad-core processor this uses just 10% of one core. HPS runs at 100 MB/s, 200 kHz event rate, 5 kHz ROC interrupt rate with 40 events/block. Event size is thus about 0.5 kB.

Miscellaneous Reports

• Sergey (mainly) and Elliott are developing a cable component for the JInventory system, should be ready in a week or so.
• Josh asked Elliott to add a new field to the JInventory system to hold telecom information.
• The techs are about ready to enter transformer, panel and circuit information into the JInventory system.
• The UPS is installed in the counting house and the 480V is connected. The RDC will be installed after Hovanes gives Paul Powers a drawing showing where it should go.
• Accelerator is working on a unified operator logbook system, not clear when it will be released, probably a few months.
• Vanik will present the status of his work on stepper motor control at the Controls meeting next week.
• We met with Accelerator to discuss transferring control of some of our power supplies to them. There is tentative agreement that they will take over four supplies, leaving just the solenoid supply for us to control (via the PLC). They also tentatively agreed to take over routine maintenance and repair of the solenoid supply, so we won't need to bring in Danfysik techs. Tim will work with them to understand costs and how to transfer money from Hall D 12GEV project and operations accounts to them.
• The PXI system Yi ordered for the fast/slow daq for the solenoid control system has arrived.
• Elliott currently has been unable to find suitable FCC Class B UPS's for applications in the hall.
• Eugene noted that a network switch hang in CLAS caused them to lose control of a polarized target, and thus lose the target. He said we need to find a way to detect and repair such a problem without turning off the beam and making an access. Elliott will follow this up with the CC network group.
• Elliott added a number of new tasks to the Mantis system suitable for summer students. We have on confirmed student who will work on one of them, not clear how many more we can get and support.