> I'm looking into using MIDAS for an experiment that creates one large event
> (20MB or more) every second.
> 
> Q1: It looks like I should use EQ_FRAGMENTED. Has this feature been in use
> recently? Is it known to work/not work?
> 
> More specifically, the computer should initiate a 1 second data taking, start to
> such the data out of the electronics (which may take a while), change some
> experimental parameters, and start over. 
> 
> Q2: What's the best way to do this? EQ_PERIODIC? 
> I cannot guarantee that the time required to read the hardware has an upper bound.
> In a standalone-prog I would simply use a big loop and let the machine execute
> it as fast as it can: 1.1s, 1.5s, 1.1s, 1.3s, 2.5s, ..... depending on the HW
> deadtimes.
> Will this work with EQ_PERIODIC?
> 
> (Sorry for these maybe stupid questions, but I have so far only used MIDAS for
> externally generated events, with <32kB event size).
> 
> 
> Thanks a lot,
> 
> Randolf

Hi Randolf,

EQ_FRAGMENTED is kind of historically, when computers had a few MB of memory and you have to play special tricks to get large data buffers through. Today I 
would just use EQ_PERIODIC and increase the midas maximal event size to your needs. For details look here:

https://midas.triumf.ca/MidasWiki/index.php/Event_Buffer

The front-end scheduler is asynchronous, which means that your readout is called when the given period (1 second) is elapsed. If the readout takes longer 
than 1s, the schedule will (hopefully) call your readout immediately after the event has been sent. So you get automatically your maximal data rate. At MEG, we 
use 2 MB events with 10 Hz, so a 20 MB/sec data rate should not be a problem on decent computers.

Best,
Stefan