Online-raw-data-nov-2012

Energies/Charges and Times

Cuts: E>0, 0<t<32 usec

Problems encountered:

• out-of-range errors, mainly for CDC and BCAL.
• too many hits in one channel (e.g. 26 for one FDC channel!)

q too large for CDC: 1790779
q too large for CDC: 1998616
q too large for CDC: 1318402
E too large for BCAL: 6214239
E too large for BCAL: 11915921
E too large for BCAL: 6686497
E too large for BCAL: 12308178
E too large for BCAL: 5799682
E too large for BCAL: 8164122

TOF

FCAL

BCAL

FDC

CDC

SC

TAG

Event Sizes and Compression

Compression

The data format for N=1 block mode readout is very verbose and redundant. Much of this is needed to allow the DAQ system to verify all crates/slots are responding properly. But once data integrity is confirmed the redundant data can be removed (perhaps at the ROC and EB levels). Note that for initial detector checkout and perhaps for early engineering runs we will write data in this format.

I propose the following strategy for removing redundant information:

• ADC: replace block header, event header, trigger time and block trailer with single "slot header" word.
• TDC: same as for ADC, additionally remove chip header and chip trailer words.
• Store trigger time in one place only.
• Remove all filler words.
• Remove slots with no hits.
• Remove crates with no hits.

Initial studies show a factor of 3 reduction in data size following this strategy.

To zip or not to zip:

Initial test shows gzip reduces the compressed file size by factor 0.60 (bzip2 by 0.44, but slower). But note that the JLab tape drives compress data upon writing/reading, so gzipping data files should NOT save any tape space. It could save disk staging space and bandwidth, but I believe we'll have plenty of both. Thus it is not clear whether gzipping data files is useful.

Tagger ADC and TDC before:

 <bank content="bank" data_type="0x10" tag="58" num="1" nchildren="1">
     <bank content="uint32" data_type="0x1" tag="0" num="1" nwords="52">
            0x808c0801     0x90800001     0x98001f40     0x88000004     0x80cc0801     
            0x90c00001     0x98001f40     0x88000004     0x810c0801     0x91000001     
            0x98001f40     0xbb001234     0xc3000006     0x88000006     0xf8000000     
            0xf8000000     0x814c0801     0x91400001     0x98001f40     0xbd801234     
            0xc5800006     0x88000006     0xf8000000     0xf8000000     0x818c0801     
            0x91800001     0x98001f40     0xbf801234     0xc7800006     0x88000006     
            0xf8000000     0xf8000000     0x81cc0801     0x91c00001     0x98001f40     
            0xba801234     0xc2800006     0x88000006     0xf8000000     0xf8000000     
            0x820c0801     0x92000001     0x98001f40     0xbd001234     0xc5000006     
            0x88000006     0xf8000000     0xf8000000     0x824c0801     0x92400001     
            0x98001f40     0x88000004     
     </bank>
  </bank>
  <bank content="bank" data_type="0x10" tag="59" num="1" nchildren="1">
     <bank content="uint32" data_type="0x1" tag="0" num="1" nwords="32">
            0x80940801     0x90800001     0x980003e8     0xa4010000     0xac01001f     
            0x88000006     0xf8000000     0xf8000000     0x80d40801     0x90c00001     
            0x980003e8     0xa4010000     0xb4861234     0xb49b1234     0xac01001f     
            0x88000008     0x81140801     0x91000001     0x980003e8     0xa4010000     
            0xb48f1234     0xb4951234     0xac01001f     0x88000008     0x81540801     
            0x91400001     0x980003e8     0xa4010000     0xb48a1234     0xac01001f     
            0xf8000000     0x88000008     
     </bank>
  </bank>

Tagger ADC and TDC after:

 <bank content="bank" data_type="0x10" tag="58" num="1" nchildren="1">
     <bank content="uint32" data_type="0x1" tag="0" num="1" nwords="15">
            0xe10c0002     0xbb001234     0xc3000006     0xe14c0002     0xbd801234     
            0xc5800006     0xe18c0002     0xbf801234     0xc7800006     0xe1cc0002     
            0xba801234     0xc2800006     0xe20c0002     0xbd001234     0xc5000006     
     </bank>
  </bank>
  <bank content="bank" data_type="0x10" tag="59" num="1" nchildren="1">
     <bank content="uint32" data_type="0x1" tag="0" num="1" nwords="8">
            0xe0d40002     0xb4861234     0xb49b1234     0xe1140002     0xb48f1234     
            0xb4951234     0xe1540001     0xb48a1234     
     </bank>
  </bank>