> I am an applied physicist at Canadian Nuclear Laboratories and am in the process 
> of migrating the full experiment configuration—including the front-end interface—
> of the CRIPT muon tomography detector from a legacy version of MIDAS (SVN Rev. 
> 5238, circa 2012) to a more modern release.
> The current system runs on Scientific Linux 6 and very old hardware. Due to 
> substantial changes in the MIDAS codebase over the years, I have encountered 
> multiple compatibility issues during the migration. I have also attempted to build 
> and run the legacy MIDAS version and the front-end code using GCC 4.8 on a modern 
> Linux system (Ubuntu 24.04), but without success.

I suggest updating the midas version. You should be able to get to at least midas 2024-12-a
without breaking anything.

> Could you please advise on the recommended approach for upgrading or refactoring 
> legacy MIDAS front-end code to the current framework? Any guidance or best 
> practices would be greatly appreciated.

Start here: https://daq00.triumf.ca/MidasWiki/index.php/Changelog
The 2019-06 release was the c -> c++ transition. Read that section carefully.
The 2020-12 update also had a change that you will also likely want to update your FEs for.

You will also likely encounter a quite a few non-midas issues related to the newer compilers.
Updates to your front ends may include things like needing to use "const char*" instead of "char*",
adding extra headers like <cstring> and <cstdlib>, using ctime_r() instead of ctime(), etc

Post back if you have specific questions.

P.S. I'm maintaining a number of midas FEs mostly written around 2007-2009.
These were running on SL5 and SL6 for many years and are now on Alma 9 with
midas 2024-12-a.

> Dear MIDAS experts,
> 
> when I attempted to increase the max number of hotlinks in ODB , defined as 
> 
> #define MAX_OPEN_RECORDS       256           /**< number of open DB records   */
> 
> I started running into an assertion in midas/src/odb.cxx
> 
> https://bitbucket.org/tmidas/midas/src/fa5457b5274a6b42c5ed8b6dea5e3cdd43de38fe/src/odb.cxx#lines-1525 :
> 
>   assert(sizeof(DATABASE_CLIENT) == 2112);
> 
> is it possible that the size of the DATABASE_CLIENT structure should be checked against 64+sizeof(OPEN_RECORD)*MAX_OPEN_RECORDS ?
> - 64 clearly can be expressed in a better maintainable form

Yes, this assert needs to be updated if you increase MAX_OPEN_RECORDS. See 
https://daq00.triumf.ca/MidasWiki/index.php/FAQ#Increasing_Number_of_Hot-links

> UPDATE: similar consideration holds for the size of the DATABLE_HEADER structure, which is also checked against a constant
> 
> https://bitbucket.org/tmidas/midas/src/fa5457b5274a6b42c5ed8b6dea5e3cdd43de38fe/src/odb.cxx#lines-1526

Yes DATABASE_HEADER can also be updated, but the associated assert()s need to be updated too.

FYI I have done both of these things and have attached patches.

Cheers,

Nick.

For the record, the ND280 (T2K near detector) MIDAS GSC was initially set up
with MAX_OPEN_RECORDS = 2560 and MAX_CLIENTS = 128.

In 2023 one fairly simple part of the detector was replaced with several 
other more complex systems (many more midas frontends, equipments, and
variables being logged) so we updated MAX_OPEN_RECORDS = 4096 and 
MAX_CLIENTS = 256.

Nick.

Dear all,

I have problem in event buffer size.

When run MIDAS, I got error "total event size (1307072) larger than buffer size
(1048576)", so I guess that the EVENT_BUFFER_SIZE is small.

I change EVENT_BUFFER_SIZE in midas.h from 0x100000 to 0x200000. After compiling
and run MIDAS, I got other error "Shared memory segment with key 0x4d040761
already exists, please remove it manually: ipcrm -M 0x4d040761 size0x204a3c" in
system.C

I check the shmget() function in system.C and it is said that error come from
Shared memory segments larger than 16,773,120 bytes and create teraspace shared
memory segments

Anyone has this problem before?
Thanks for your help

M.T

Dear all,

I have problem in event buffer size.

When run MIDAS, I got error "total event size (1307072) larger than buffer size
(1048576)", so I guess that the EVENT_BUFFER_SIZE is small.

I change EVENT_BUFFER_SIZE in midas.h from 0x100000 to 0x200000. After compiling
and run MIDAS, I got other error "Shared memory segment with key 0x4d040761
already exists, please remove it manually: ipcrm -M 0x4d040761 size0x204a3c" in
system.C

I check the shmget() function in system.C and it is said that error come from
Shared memory segments larger than 16,773,120 bytes and create teraspace shared
memory segments

Anyone has this problem before?
Thanks for your help

M.T

I am sorry for my late reply memory in my PC is 16 GB I check the contents of .SHM_TYPE.TXT and it is "POSIXv2_SHM". But there is no buffer sizes in "/Experiment" After run "ipcrm -M 0x4d040761 size0x204a3c", remove .SYSTEM.SHM and run MIDAS again, I still get error "Shared memory segment with key 0x4d040761 already exists, please remove it manually: ipcrm -M 0x4d040761 size0x204a3c" M.T

I am sorry for my late reply 

memory in my PC is 16 GB 

I check the contents of .SHM_TYPE.TXT and it is "POSIXv2_SHM". 
But there is no buffer sizes in "/Experiment" 

After run "ipcrm -M 0x4d040761 size0x204a3c", remove .SYSTEM.SHM and run MIDAS again, I still get error "Shared memory segment
with key 0x4d040761 already exists, please remove it manually: ipcrm -M 0x4d040761 size0x204a3c" M.T

Please, tell me how to choose a value of a "key" like DCM, pulser period,
presamples, upper thresholds to run a experiment? where can I find the related
informations? 

Hello there,

I am working on a task that involves some ODB changes that happen within 20-500 
ms. The wait command for Midas Sequencer only works for > 1 second. As a 
workaround, I tried calling a python script that has a time.sleep() command, but 
the sequencer doesn't wait for the python script to terminate before moving to the 
next command. Obviously, I could just move the entire script to python, but that 
would cause further issues to us. Is there a way to have a wait that has precision 
in order of milliseconds from within the Midas Sequencer? If there is no Midas-
native methods for doing this, what workaround will you suggest to get this to 
work?

> > Ok, I implemented the float second wait function. Internally it works in ms, so the maximum resolution is 0.001 s.
> > 
> > Best,
> > Stefan
> 
> Thank you, we will test this soon and let you know if we see any issues (but we're not expecting any).

Hello Stefan,

Thank you for the help you provided for us so far. I tried your code changes on our midas fork. Now, I notice that any 
wait command takes at least 0.2 seconds to run. 

For example, when I use the following script:
SCRIPT source scripts/time_print.sh
WAIT Seconds, 0.1
SCRIPT source scripts/time_print.sh
WAIT Seconds, 0.1
SCRIPT source scripts/time_print.sh

The time_print.sh script prints time segments separated by almost exactly 0.2 seconds. Same goes for when I use 0.01 
second waits.

However, when I use 0.2 seconds wait, then I get time segments separated by 0.3 seconds. I also tried something like 
this:
SCRIPT source scripts/time_print.sh
WAIT Seconds, 0.2
WAIT Seconds, 0.2
SCRIPT source scripts/time_print.sh
WAIT Seconds, 0.2
WAIT Seconds, 0.2
SCRIPT source scripts/time_print.sh

This script results in time segements of 0.6 seconds difference. It is not immidiately clear to me from the sequencer 
code what causes this effect. The code as it stands is a lot better than what we had before the changes, but I am 
wondering if this can be reduced to the order of 1ms or 10ms.

Best regards,
Musaab Faozi

> Actually I realized that a 1ms wait still works, so I reduced it to that.
> 
> Stefan

Thank you so much, Stefan. I have tested your changes, and it seems like this does 
the job for our purposes. Very appreciated!

Best regards,
Musaab Faozi

In midas.c, the bk_delete function removes a bank by decrementing the total
event size and then copying the remaining banks into the location of the first
using memcpy from string.h.

memcpy is not specified to handle overlapping memory regions (such as MIDAS
banks), though it seems most common implementations do.

memmove should be used instead, which is specified to behave as if copying
through an intermediate buffer.

I noticed the misbehavior using glibc with gcc version 4.4.4 and scientific
linux 6.0. Other gcc versions changed nothing, as this originates from the
implementation of memcpy in libc.

libc version:
GNU C Library stable release version 2.12, by Roland McGrath et al.
Compiled by GNU CC version 4.4.5 20110214 (Red Hat 4.4.5-6).
Compiled on a Linux 2.6.32 system on 2011-12-06.

I am using the MSCB SCS2000 to monitor slow control variables (temperatures, voltages, etc). I am trying to 
get it set up at fermilab as a test stand in the MC1 building and was wondering if anyone has integrated 
Midas with a MSCB SCS2000 before. We have two systems at fermilab, one system that is currently running 
in the g-2 experimental hall, but running an out of date version of midas. The second test stand I am 
setting up is working with the current version of midas. I believe we will easily be able to figure out the 
external probes for temperatures and voltages just fine. But the MSCB SCS2000 box itself has 1 
temperature value, 1 current value, and 5 voltages internally that we also need to monitor. If I use the msc 
command I can read back the external values through the daughter cards I have installed on the SCS2000 
box but has no way of reading back the internal values that I need. I also have been looking through the 
MIDAS files trying to find a possible way to read these out to no avail.

If anyone has any ideas or has had previous work with the SCS2000 and knows how to read back the 
internal values please let me know. 

Thanks,

Michael McEvoy
NIU Graduate Student

As the Midas software is installed using CMake, it can be easily integrated into 
other CMake projects using the MidasConfig.cmake file produced during the Midas 
installation.

This file points to the location of the include and libraries of Midas using three 
variables:
- MIDAS_INCLUDE_DIRS
- MIDAS_LIBRARY_DIRS
- MIDAS_LIBRARIES

Then the CMakeLists file of the new project can use the CMake find_package 
functionalities like:
```
find_package (Midas REQUIRED)
if (MIDAS_FOUND)
    MESSAGE(STATUS "Found midas: libraries ${MIDAS_LIBRARIES}")
    pbuilder_add_ext_libraries (${MIDAS_LIBRARIES})
else (MIDAS_FOUND)
    message(FATAL "Unable to find midas")
endif (MIDAS_FOUND)
include_directories (${MIDAS_INCLUDE_DIR})
```
pbuilder_add_ext_libraries is a CMake macro allowing to automatically add the 
libraries into the project: this macro can be found here: 
https://github.com/project8/scarab/blob/master/cmake/PackageBuilder.cmake
If such macro doesn't exist, the linkage to each executable/library can be done 
similarly to https://midas.triumf.ca/elog/Midas/1964 using: 

```
target_link_libraries(crfe ${MIDAS_LIBARIES} ${LIBS})
```

The current version of the MidasConfig.cmake is minimal and could for example 
include a version number: this would allow to define a e.g. minimal version of 
Midas needed by the new project.

Hi,

Using midas version 12-2020,  I am trying to run mhttpd from within a docker container using docker-compose.
Starting from an empty ODB, I simply run `mhttpd` and this is the output I have:
midas_hatfe_1  | <Warning> Starting mhttpd...
midas_hatfe_1  | [mhttpd,INFO] ODB subtree /Runinfo corrected successfully
midas_hatfe_1  | MVOdb::SetMidasStatus: Error: MIDAS db_find_key() at ODB path "/WebServer/Host list" returned status 312
midas_hatfe_1  | Mongoose web server will not use password protection
midas_hatfe_1  | Mongoose web server will not use the hostlist, connections from anywhere will be accepted
midas_hatfe_1  | Mongoose web server listening on http address "localhost:8080", passwords OFF, hostlist OFF
midas_hatfe_1  | [mhttpd,ERROR] [mhttpd.cxx:19160:mongoose_listen,ERROR] Cannot mg_bind address "[::1]:8080"

According to the documentation, the WebServer tree should be created automatically when starting the mhttpd; but it seems not as it doesn't find the entry "/WebServer/Host list".
If I create it by end (using "create STRING /WebServer/Host list"), I still get the error message that mhttpd didn't bind properly to the local port 8080.
I am not sure what it wrong, as mhttpd is working perfectly well in this exact container for midas 03-2020.

Any idea what difference makes it not possible anymore to run into these container?

Thanks very much for your help.
Cheers
Mathieu

> > It looks like mhttpd managed to bind to the IPv4 address (localhost), but not the IPv6 address (::1). If you don't need it, try setting "/Webserver/Enable IPv6" to false.
> 
> We had this issue already several times. This info should be put into the documentation at a prominent location.
> 
> Stefan

Thanks a lot, this solved my issue!

Hi,

I am running a simple FE executable that is supposed to define a PRAW DWORD bank.
The issue is that, right after the start of the run, the logger crashes without messages.
Then the FE reports this error, which is rather confusing.
```
12:59:29.140 2021/05/24 [feTestDatastruct,ERROR] [odb.cxx:6986:db_set_data1,ERROR] "/Equipment/Trigger/Variables/PRAW" is of type UINT32, not UINT32
```

Dear all,

For my personal convenience, I started to add an homebrew formula
for
midas (*):
https://github.com/guiguem/homebrew-tap/blob/main/Formula/
midas.rb
It
is convenient in particular to deploy as it automatically gets all
the right
dependencies; for MacOS (**), there are bottles already available.

The
installation would then be
brew tap guiguem/tap
brew install midas

I
thought I
would share it here, if this is helpful to someone else (***).
This
was tested
rather extensively, including the development of manalyzer modules
using this
bottled version as backend.
A possible upgrade (if people are
interested) would
be to develop/deploy a "mainstream" midas version (and I would
rename mine
"midas-mod").

Cheers
Mathieu
-----
Notes:
(*) The version installed
by this
formula is a very slightly modified version of midas, designed to
support more
than 100 front-ends (needed for HK).
See commits here:
https://
gitlab.in2p3.fr/
hk/clocks/midas/-/
commit/060b77afb38e38f9a3155d2606860f12d680f4de
https://
gitlab.in2p3.fr/hk/
clocks/midas/-/
commit/1da438ad1946de7ba697e849de6a6675ac45ebb8
I have the
recollection this
version might not be compatible with the main midas one. 

(**) I also have some
stuff for Ubuntu, but Ubuntu seems to do additional
linkage to curl which needs
to be handled (easy).
That being said the
installation from sources works fine!
(***) Some oddities were unraveled such as
the fact that the build_interface
pointing to the source include directory are
still appearing in the
midasConfig.cmake files (leading to issues in brew). This
was fixed by replacing
the faulty path to the final installation location. Maybe
this should be fixed ? 

Thanks Stefan!
Actually, these two approaches are slightly different I guess:
- the installation script you are linking manages the
installation and the subsequent steps, but doesn't manage the dependencies: for instance on my machine, it didn't find root and so manalyzer
is built without root support.
Maybe this is just something to adapt?
Brew on the other hand manages root and so knows how to link these two
together.
- The nice thing I like about brew is that one can "ship bottles" aka compiled version of the code; it is great and fast for
deployment and avoid compilation issues.
- I like that your setup does deploy and launch all the necessary executables ! I know brew can do
this too via brew services (see an example here: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/r/rabbitmq.rb#L83 ), maybe worth
investigating...?
- Brew relies on code tagging to better manage the bottles, so that it uses the tag to get a well-defined version of the
code and give a name to the version.
I had to implement my own tags e.g. midas-mod-2025-12-a to get a release.
I am not sure how to do in the
case of midas where the tags are not that frequent...

Thank you for the feedback, I will make the modifications (aka naming my formula
``midas-mod'') so that it doesn't collide with a future official midas one.

Concerning the MidasConfig.cmake issue, this is what I need
(note that the INTERFACE_INCLUDE_DIRECTORIES is pointing to 
/opt/homebrew/Cellar/midas/midas-mod-2025-12-a/)

set_target_properties(midas::midas PROPERTIES
  INTERFACE_COMPILE_DEFINITIONS "HAVE_CURL;HAVE_MYSQL;HAVE_SQLITE;HAVE_FTPLIB"
 INTERFACE_COMPILE_OPTIONS "-I/opt/homebrew/Cellar/mariadb/12.1.2/include/mysql;-I/opt/homebrew/Cellar/mariadb/12.1.2/include/mysql/mysql"
 INTERFACE_INCLUDE_DIRECTORIES "/opt/homebrew/Cellar/midas/midas-mod-2025-12-a/;${_IMPORT_PREFIX}/include"
  INTERFACE_LINK_LIBRARIES "/opt/
homebrew/opt/zlib/lib/libz.dylib;-lcurl;-L/opt/homebrew/Cellar/mariadb/12.1.2/lib/ -lmariadb;/opt/homebrew/opt/sqlite/lib/libsqlite3.dylib"
)

whereas by default INTERFACE_INCLUDE_DIRECTORIES points to the source code location (in the case of brew, something like /private/<some-
hash> ).
Brew deletes the source code at the end of the installation, whereas midas seems to rely on the fact that the source code is still
present...
Does it help?
A way to fix is to search for this ``/private'' path and replace it, but this isn't ideal I guess...
This is what I
did in the midas formula:
--------
# Fix broken CMake export paths if they exist
    cmake_files = Dir["#{lib}/**/*manalyzer*.cmake"]
   cmake_files.each do |file|
      if File.read(file).match?(%r{/private/tmp/midas-[^/"]+})
        inreplace file, %r{/private/tmp/midas-
[^/"]+},
prefix.to_s
      end
      inreplace file, %r{/tmp/midas-[^/"]+}, prefix.to_s if File.read(file).match?(%r{/tmp/midas-[^/"]+})
   end
    cmake_files = Dir["#{lib}/**/*midas*.cmake"]
    cmake_files.each do |file|
      if File.read(file).match?(%r{/private/tmp/midas-
[^/"]+})
        inreplace file, %r{/private/tmp/midas-[^/"]+},
prefix.to_s
      end
      inreplace file, %r{/tmp/midas-[^/"]+},
prefix.to_s if File.read(file).match?(%r{/tmp/midas-[^/"]+})
    end
-----

I guess this code could be changed into some bash commands and
added to your script?

Thank you very much again!
Mathieu


> Hi Mathieu,
> 
> thanks for your contribution. Have you looked at the
install.sh script I developed last week:
> 
>    https://daq00.triumf.ca/MidasWiki/index.php/Install_Script
> 
> which basically does the
same, plus it modifies the environment and installs mhttpd as a service.
> 
> Actually I modeled the installation after the way Homebrew is
installed in the first place (using curl).
> 
> I wonder if the two things can kind of be integrated. Would be great to get with brew always
the newest midas version, and it would also 
> check and modify the environment. 
> 
> If you tell me exactly what is wrong
MidasConfig.cmake.in I'm happy to fix it.
> 
> Best,
> Stefan

Hi

I had a problem with the compilation of midas after an OS update to the recent version of OpenSuse tumbleweed. The function stime() in system.cxx:3196 is no longer available. 

In the documentation it is also marked as deprecated with the suggestion to use clock_settime instead:
https://man7.org/linux/man-pages/man2/stime.2.html

replacing system.cxx:3196 with the clock_settime - method in system.cxx:3200 - 3204 also for OS_UNIX seems to solve the problem, but i'm not sure if this will cause problems on older OS's.

Martin