This message (now translated to html) was sent Thu Oct 21 17:44:54 MDT 1999. It was sent to chiu@nevis1.nevis.columbia.edu (Mickey Chiu), nagle@nevis1.nevis.columbia.edu (Jamie Nagle), chi@nevis.nevis.columbia.edu (Cheng-Yi Chi) ygkim@p2hp2.lanl.gov (Young Gook Kim)
Subject: mvd chaintest

Hi,

You guys may be interested in knowing that I ran about 50K packets through the MVD DAQ chain into the DCM. The chain is as I described it in a message to the MVD list-server and to a few other interested parties on Monday October 18. Briefly, it contained 2 MCM's, power/comm board, motherboard, TCIM, DCIM, a homemade card for Arcnet, mini-DAQ, a DCM+controller+crate, 2 PCs, one hp-unix system, misc cables, assorted software. I wrote the data to disk (on the hp) and analyzed (with a simple program I wrote) for

1) "horizontal" and "vertical" parity errors
2) correct format of packets including:
   a) first words has 1st 16 bits all=1
   b) the detector ID word (=2) is correct
   c) user word 8 (a word constructed by the DCIM) has the correct
      settings of these bits:
      i)   bit 10 = 0 (means valid data packet present in DCIM)
      ii)  bit 11 = 0 (1 means packet too short)
      iii) bit 12 = 0 (1 means no stop sequence seen)
      iv)  bit 13 = 0 (1 means 2 consecutive start sequences seen)
3) ADC values returned in each packet are 0,1,2,...255 for every
   event. This should be true because I put the MCM's in a test mode
   where they send out these well defined results in response to
   any level 1.

I did this run in "multi-plexed mode" -- the one DCIM fiber I was using sent out data from two MCM's on the same fiber. This means that each level-1 trigger results in two packets sent to the DCM. I ran at very low (and fixed) trigger frequency (3Hz) because I wanted to run for a long time and had finite disk space. The total number of "events" reported by the dcm program was 49282, which is exactly consistent with 2 packets per event and the 24641 level-1 triggers I sent. However, the output file contained only 1012 valid events, the size of the file makes it clear that the remaining data was not in the file. There were no problems with the events which were in the output file.

I got error messages from the "dcm" program which runs on the VME crate controller -- it gave messages which said:

0xbc1de0 (tStartRun): memPartAlloc: block too big - 524 in partition 0x1bb80c.

approximately once per 1000 packets (the frequency looked random to me) while it was running. When I tried to stop the run, it gave the same message again and then seemed to crash.

Do you know anything about this?

Regards,
John
PS -- I will leave it to run overnight tonight.