The epics frontend overwrites the "start command" odb after each start:

  // set start command in ODB
   midas::odb efe("/Programs/EPICS Frontend");
   std::string p(__FILE__);
   std::string s("build/epics_fe");
   auto i = p.find("epics_fe.cxx");
   p.replace(i, s.length(), s);
   p = p.substr(0, i + s.length());
   efe["Start command"].set_string_size(p, 256);

this should be set such that it only writes when the key is not there. It causes the following issue: on a pc with multiple experiments defined, you need to start the fe's with a "-e <name>" flag. 

Another small user experience request:

When making a link in the odb (web interface) a nice browser window pop's up. There is however not scrolling possible in the window. As a result, you can not reach a odb key if it is nested to deeply. 

Trying to type out the Link target in the field only allows for 32 characters

context: we are setting up a bunch of Links in the History

We switched from the history files from MIDAS to FILE, so we have *.dat files now (per variable), instead of the old *.hst. 

How shoul
d one now extract data from these data files? With the old *,hst files I can e.g. mhdump -E 102 231010.hst 

but with the new *.dat files I get

...2023/history$ mhdump -E 0 -T "Run number" mhf_1697445335_20231016_run_transitions.dat | head -n 15
event name: [Run transitions], time [1697445335]
tag: tag: /DWORD 1 4 /timestamp
tag: tag: UINT32 1 4 State
tag: tag: UINT32 1 4 Run number
record size: 12, data offset: 1024
record 0, time 1697557722, incr 112387
record 1, time 1697557783, incr 61
record 2, time 1697557804, incr 21
record 3, time 1697557834, incr 30
record 4, time 1697557888, incr 54
record 5, time 1697558318, incr 430
record 6, time 1697558323, incr 5
record 7, time 1697558659, incr 336
record 8, time 1697558668, incr 9
record 9, time 1697558753, incr 85

not very intelligible

Yes, I can do csv export on the webpage. But it would be nice to be able to extract from just the files. Also, the webpage export only saves the data shown ( range limited and/or downsampled)

> $ cat mhf_1697445335_20231016_run_transitions.dat
> event name: [Run transitions], time [1697445335]
> tag: tag: /DWORD 1 4 /timestamp
> tag: tag: UINT32 1 4 State
> tag: tag: UINT32 1 4 Run number
> record size: 12, data offset: 1024
> ...
> 
> data is in fixed-length record format. from the file header, you read "record size" is 12 and data starts at offset 1024.
> 
> the 12 bytes of the data record are described by the tags:
> 4 bytes of timestamp (DWORD, unix time)
> 4 bytes of State (UINT32)
> 4 bytes of "Run number" (UINT32)
> 
> endianess is "local endian", which means "little endian" as we have no big-endian hardware anymore to test endian conversions.
> 
> file format is designed for reading using read() or mmap().
> 
> and you are right mhdump, does not work on these files, I guess I can write another utility that does what I just described and spews the numbers to stdout.
> 
> K.O.


Thanks for the answer. As this FILE system is advertised as the new default (eog:2617), this format does merit some more WIKI info.

Dear experts,
    we have a problem when trying to run a MIDAS DAQ which worked in the past on the same PC (but on a different
network). We get the following error messages when starting a new run:

Wed Apr 26 23:03:12 2017 [mhttpd,ERROR] [midas.c:9106:rpc_client_connect,ERROR] cannot connect to host "scar
lett", port 44858: connect() returned -1, errno 113 (No route to host)
Wed Apr 26 23:03:12 2017 [mhttpd,ERROR] [midas.c:3539:cm_transition_call,ERROR] cannot connect to client "Lo
gger" on host scarlett, port 44858, status 503

(scarlett is indeed the hostname of the PC). The error occurs even if the PC is disconnected from the network.

Any suggestion?

Best Regards,
        Francesco

Dear Stefan,
           thank you very much for your reply. We could finally fix the problem by replacing "scarlett" with "scarlett.localdomain" in our
hostname configuration file /etc/hostname (under debian).

Best Regards,
        Francesco

> Dear Francesco,
> 
> Your error (No route to host) typically means that you have a network problem outside of MIDAS. Your computer has to "find itself" and 
> this is probably broken. Try to do a "ping scarlett" or "nslookup scarlett" and you will see that the DNS server can't be reached or is 
> wrongly configured. Sometimes it helps to put scarlett explicitly into /etc/hosts
> 
> Stefan
> 
> 
> > Dear experts,
> >     we have a problem when trying to run a MIDAS DAQ which worked in the past on the same PC (but on a different
> > network). We get the following error messages when starting a new run:
> > 
> > Wed Apr 26 23:03:12 2017 [mhttpd,ERROR] [midas.c:9106:rpc_client_connect,ERROR] cannot connect to host "scar
> > lett", port 44858: connect() returned -1, errno 113 (No route to host)
> > Wed Apr 26 23:03:12 2017 [mhttpd,ERROR] [midas.c:3539:cm_transition_call,ERROR] cannot connect to client "Lo
> > gger" on host scarlett, port 44858, status 503
> > 
> > (scarlett is indeed the hostname of the PC). The error occurs even if the PC is disconnected from the network.
> > 
> > Any suggestion?
> > 
> > Best Regards,
> >         Francesco

Dear expert,
      I'm developing a frontend and I'm getting this kind of error at each event:

10:14:56.564 2018/05/04 [Sample Frontend,ERROR] [odb.c:5911:db_set_data1,ERROR]
online database full

If I run the mem command in odbedit I get the result at the end of this post.

Notice that I need to use an event size which is significantly larger than the
default one. I don't know if it is relevant for this error. I have in the ODB:

  /Experiment/MAX_EVENT_SIZE = 900000000

and in the frontend code:

  /* maximum event size produced by this frontend */
  INT max_event_size = 300000000;

  /* maximum event size for fragmented events (EQ_FRAGMENTED) */
  INT max_event_size_frag = 5 * 1024 * 1024;

  /* buffer size to hold events */
  INT event_buffer_size = 600000000;

Events seem to be properly stored in the output files, but I'm afraid I could
get some other problem.

Thank you for your help,
         Francesco

-------------------------------------------------------------------------

Database header size is 0x21040, all following values are offset by this!
Key area  0x00000000 - 0x0007FFFF, size 524288 bytes
Data area 0x00080000 - 0x00100000, size 524288 bytes

Keylist:
--------
Free block at 0x00000B58, size 0x00000008, next 0x000053E0
Free block at 0x000053E0, size 0x00000008, next 0x00006560
Free block at 0x00006560, size 0x00079AA0, next 0x00000000

Free Key area: 498352 bytes out of 524288 bytes

Data:
-----
Free block at 0x000847F0, size 0x0007B810, next 0x00000000

Free Data area: 505872 bytes out of 524288 bytes

Free: 498352 (95.1%) keylist, 505872 (96.5%) data

Dear experts,
              is there any way to launch an executable script on the host computer from the MIDAS 
sequencer? If not, is there any interest to develop such a feature?

Thank you,
         Francesco

Dear all,
        I need to implement a DAQ sequence where a short run (100 events, which takes a couple of 
minutes) is taken every hour, with a long run in between two short runs. In the sequencer, I can do:

LOOP infinite

.... some ODB settings ....
     TRANSITION START
     WAIT events 100
     TRANSITION STOP

.... some ODB settings ....
     TRANSITION START
     WAIT seconds 3600
     TRANSITION STOP

ENDLOOP


I have two questions: 

- for the long run, I want to write on disk only a maximum number of events. I think I can suppress 
the event polling in the frontend, with an ODB query of the number of collected events. I'm 
wondering if there is a smarter way to do that. It is also ok if the run is stopped after a maximum 
number of events, but the subsequent short run should still start exactly after 1h from the previous 
short run. 

- with the script above, the real time lapse between the start of two short runs would depend on 
the duration of the short run itself. Is there a way to start the short run exactly 1 h after the starting 
of the previous short run?

Thank you in advance for your help,
              Francesco

Dear all,
         I'm running a DAQ frontend and it works well if one single run is
taken. If I try to take a second run right after, the run is performed but, when
stopping it, I get the error messages below. Any hint?

Thank you for your help,
      Francesco


11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:6022:cm_shutdown,ERROR] Killing
and Deleting client 'cygnus_daq' pid 12472

11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:6019:cm_shutdown,ERROR] Cannot
connect to client 'cygnus_daq' on host 'localhost', port 46341

11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:9539:rpc_client_connect,ERROR]
cannot connect to host "localhost", port 46341: connect() returned -1, errno 111
(Connection refused)

11:42:24.012 2019/03/12 [mhttpd,ERROR] [midas.c:10821:rpc_client_call,ERROR]
call to "cygnus_daq" on "localhost" RPC "rc_transition": error,
ss_recv_net_command() status 411

11:42:24.012 2019/03/12 [mhttpd,ERROR] [system.c:4715:ss_recv_net_command,ERROR]
error receiving network command header, see messages

11:42:24.011 2019/03/12 [mhttpd,ERROR] [system.c:4661:recv_tcp2,ERROR]
unexpected connection closure

11:42:23.994 2019/03/12 [cygnus_daq,ERROR] [midas.c:1951:,ERROR]
cm_disconnect_experiment not called at end of program

Dear all,
       I'm trying to compile MIDAS on MacOS 10.10 and I get this error:

/Users/francesco/MIDAS/midas/src/system.cxx:3187:18: error: use of undeclared identifier 
'CLOCK_REALTIME'
   clock_settime(CLOCK_REALTIME, &ltm);

Is it related to my (old) version of MacOS? Can I fix it somehow?

Thank you,
      Francesco

Dear all,
      I'm trying to use the logging on a mysql DB. Following the instructions on 
the Wiki, I recompiled MIDAS after installing mysql, and cmake with NEED_MYSQL=1 
can find it:

-- MIDAS: Found MySQL version 8.0.23

Then, I compiled my frontend (cmake with no options + make) and run it, but in the 
ODB I cannot find the tree for mySQL. I have only:

Logger/Runlog/ASCII

while I would expect also:

Logger/Runlog/SQL

What could be missing? Maybe should I add something in the CMakeList file or run 
cmake with some option?

Thank you,
      Francesco

I solved this, it was a failed "make clean" before recompiling. Now it works.

Sorry for the noise.

Francesco

> Dear all,
>       I'm trying to use the logging on a mysql DB. Following the instructions on 
> the Wiki, I recompiled MIDAS after installing mysql, and cmake with NEED_MYSQL=1 
> can find it:
> 
> -- MIDAS: Found MySQL version 8.0.23
> 
> Then, I compiled my frontend (cmake with no options + make) and run it, but in the 
> ODB I cannot find the tree for mySQL. I have only:
> 
> Logger/Runlog/ASCII
> 
> while I would expect also:
> 
> Logger/Runlog/SQL
> 
> What could be missing? Maybe should I add something in the CMakeList file or run 
> cmake with some option?
> 
> Thank you,
>       Francesco

Dear experts,
       while trying to readout a MIDAS file from a python script. I get the error below at the very first event. Any hint?

Thank you very much,
            Francesco

  File "/home/cygno/DAQ/offline/file_reader.py", line 9, in <module>
    for event in mfile:
  File "/home/cygno/DAQ/python/midas/file_reader.py", line 159, in __next__
    ev = self.read_next_event()
  File "/home/cygno/DAQ/python/midas/file_reader.py", line 264, in read_next_event
    return self.read_this_event_body()
  File "/home/cygno/DAQ/python/midas/file_reader.py", line 307, in read_this_event_body
    self.event.unpack_body(body_data, 0, self.use_numpy)
  File "/home/cygno/DAQ/python/midas/event.py", line 648, in unpack_body
    bank.fill_header_from_bytes(bank_header_data, self.is_bank_32(), self.is_bank_data_64bit_aligned())
  File "/home/cygno/DAQ/python/midas/event.py", line 298, in fill_header_from_bytes
    self.name = "".join(x.decode('ascii') for x in unpacked[:4])
  File "/home/cygno/DAQ/python/midas/event.py", line 298, in <genexpr>
    self.name = "".join(x.decode('ascii') for x in unpacked[:4])
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc8 in position 0: ordinal not in range(128)

Dear all,
     I need to integrate in my MIDAS project the communication with an OPC UA 
server. My plan is to develop an OPC UA client as a "device" in 
midas/drivers/device.

Two questions:

1) Is anybody aware of some similar effort for some other project, so that I can 
get some example?

2) What could be the more appropriate driver's class to be used? generic.cxx? 
multi.cxx?

Thank you for your help,
           Francesco

Dear all,
      I am trying to make the MIDAS web server for my DAQ project accessible from other machines. In the ODB, I activated the necessary flags:

[local:CYGNUS_RD:S]/WebServer>ls
Enable localhost port           y
localhost port                  8080
localhost port passwords        n
Enable insecure port            y
insecure port                   8081
insecure port passwords         y
insecure port host list         y
Enable https port               y
https port                      8443
https port passwords            y
https port host list            n
Host list
                                localhost
Enable IPv6                     y
Proxy                           
mime.types

Following the instructions on the Wiki I enabled the SSL support. When running mhttpd, I get these messages:

Mongoose web server will use HTTP Digest authentication with realm "CYGNUS_RD" and password file "/home/cygno/DAQ/online/htpasswd.txt"
Mongoose web server will use the hostlist, connections will be accepted only from: localhost
Mongoose web server listening on http address "localhost:8080", passwords OFF, hostlist OFF
Mongoose web server listening on http address "[::1]:8080", passwords OFF, hostlist OFF
Mongoose web server listening on http address "8081", passwords enabled, hostlist enabled
[mhttpd,ERROR] [mhttpd.cxx:19166:mongoose_listen,ERROR] Cannot mg_bind address "[::0]:8081"
Mongoose web server will use https certificate file "/home/cygno/DAQ/online/ssl_cert.pem"
Mongoose web server listening on https address "8443", passwords enabled, hostlist OFF
[mhttpd,ERROR] [mhttpd.cxx:19166:mongoose_listen,ERROR] Cannot mg_bind address "[::0]:8443"

and the server is not accessible from other machines. Any suggestion to solve or better investigate this problem?

Thank you very much,
         Francesco

It worked, thank you very much!

Francesco

> > Enable IPv6                     y
> 
> Probably the IPv6 problem, see here elog:2269
> 
> I asked to turn off IPv6 by default, or at least mention this in the documentation,
> but unfortunately nothing happened.
> 
> Stefan

Hello,
     I'm experiencing crashes of the mlogger program on the time scale of a couple 
of days. The only messages from MIDAS are:

05:34:47.336 2021/10/24 [mhttpd,INFO] Client 'Logger' (PID 14281) on database 
'ODB' removed by db_cleanup called by cm_periodic_tasks (idle 10.2s,TO 10s)
05:34:47.335 2021/10/24 [mhttpd,INFO] Client 'Logger' on buffer 'SYSMSG' removed 
by cm_periodic_tasks (idle 10.2s, timeout 10s)

Any suggestion to further investigate this issue?

Thank you very much,
         Francesco

Dear all,
       I've a frontend writing a quite big bunch of data into a MIDAS bank (16bit output from a 4MP photo camera). 
I'm experiencing a writing speed problem that I don't understand. When the photo camera is triggered at a low rate (< 2 Hz) 
writing into the bank takes a very short time for each event (indeed, what I measure is the time to write and go back 
into the polling function). If I increase the rate to 4 Hz, I see that writing the first two events takes a sort time, 
but the third event takes a very long time (hundreds of ms), then again the fourth and fifth events are very fast, and 
the sixth is very slow. If I further increase the rate, every other event is very slow. The problem is not in the readout 
of the camera, because if I just remove the bank writing and keep the camera readout, the problem disappears. Can you 
explain this behavior? Is there any way to improve it?

Below you can also find the code I use to copy the data from the camera buffer into the bank. If you have any suggestion 
to improve it, it would be really appreciated.

Thank you very much,
          Francesco



  const char* pSrc = (const char*)bufframe.buf;

  for(int y = 0; y < bufframe.height; y++ ){

    //Copy one row
    const unsigned short* pDst = (const unsigned short*)pSrc;

    //go through the row
    for(int x = 0; x < bufframe.width; x++ ){

      WORD tmpData = *pDst++; 

      *pdata++ = tmpData;

    }

    pSrc += bufframe.rowbytes;

  }
 

Dear all,
        I finally succeeded to get a working driver for the communication with an OPC 
UA server. It is based on the open62541 library and I use it in combination with the 
generic.h driver class. This is still a crude implementation, but let me post it here, 
maybe it can be useful to somebody else.

BTW, if there is somebody more skilled than me with OPC UA and MIDAS drivers, who is 
willing to give suggestions for improving the implementation, it would be extremely 
appreciated.

Best Regards,
      Francesco



> Dear all,
>      I need to integrate in my MIDAS project the communication with an OPC UA 
> server. My plan is to develop an OPC UA client as a "device" in 
> midas/drivers/device.
> 
> Two questions:
> 
> 1) Is anybody aware of some similar effort for some other project, so that I can 
> get some example?
> 
> 2) What could be the more appropriate driver's class to be used? generic.cxx? 
> multi.cxx?
> 
> Thank you for your help,
>            Francesco