Hi,
I'm new to both Linux and Midas and having trouble installing the programme - 
the install file suggeats that I should have a directory:

midas/unix

but this doesn't appear.

Also, when running the "make" for the library (step 3 of the installation), I 
don't see the directory "zlib.a", but there is a "libz.a" and I note the 
original .tar file has no libz.a file in it. Is this a typo on the 
installation?
The terminal window at this point displays:

undefined reference to `errno'
make: ***[example] Error 1

Further help will no doubt be required as I've used windows throughout my 
research and now looking to learn how to use linux. Any help greatly 
appreciated. Thanks!

Fresh svn checkout of MIDAS does not build on Fedora 5, I get this error:

cc -c -g -O2 -Wall -Wuninitialized -Iinclude -Idrivers -I../mxml -Llinux/lib
-DINCLUDE_FTPLIB   -D_LARGEFILE64_SOURCE -DHAVE_ROOT -pthread
-I/triumfcs/trshare/olchansk/root/root_v5.10.00_SL40/include -m32 -DOS_LINUX
-fPIC -Wno-unused-function -o linux/lib/odb.o src/odb.c
src/odb.c: In function 'db_open_database':
src/odb.c:805: warning: dereferencing type-punned pointer will break
strict-aliasing rules
src/odb.c: In function 'db_lock_database':
src/odb.c:1350: warning: dereferencing type-punned pointer will break
strict-aliasing rules
cc: Internal error: Segmentation fault (program cc1)
Please submit a full bug report.
See <URL:http://bugzilla.redhat.com/bugzilla> for instructions.
make: *** [linux/lib/odb.o] Error 1

If I compile odb.c without "-O2", the rest of MIDAS builds without any more errors.

The observed warnings are (I do not know what they mean):
warning: dereferencing type-punned pointer will break strict-aliasing rules
warning: missing sentinel in function call (Cannot do without sentinels, eh?)
warning: pointer targets in passing argument 3 of 'getsockname' differ in signedness
warning: non-local variable '<anonymous struct> out_info' uses anonymous type

The "invalid lvalue" errors seem to have been successfully vanquished.

K.O.

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?

I guess the simplest way to do that without breaking with existing code is to change the 
second number to a float. So a

WAIT SECONDS, 1

will still work, and you can then write

WAIT SECONDS, 0.01

to get a 10 ms wait. Would that work for you?

Stefan

> I guess the simplest way to do that without breaking with existing code is to change the 
> second number to a float. So a
> 
> WAIT SECONDS, 1
> 
> will still work, and you can then write
> 
> WAIT SECONDS, 0.01
> 
> to get a 10 ms wait. Would that work for you?

This would work fine in principle, but isn't implemented in the current MIDAS sequencer as we understand it.  (We tried!) Is your proposal to rewrite the sequencer 
to allow fractional waits?  Right now the code seems to store the start_time as a DWORD and uses atoi to parse the wait time, and uses ss_time (which seems only get
the time to the nearest second) to fetch the time.

> This would work fine in principle, but isn't implemented in the current MIDAS sequencer as we understand it.  (We tried!) Is your proposal to rewrite the sequencer 
> to allow fractional waits?  Right now the code seems to store the start_time as a DWORD and uses atoi to parse the wait time, and uses ss_time (which seems only get
> the time to the nearest second) to fetch the time.

No it's not implemented, was just my idea. If it would work for you, I can implement it in the next couple of days.

Stefan

> > This would work fine in principle, but isn't implemented in the current MIDAS sequencer as we understand it.  (We tried!) Is your proposal to rewrite the sequencer 
> > to allow fractional waits?  Right now the code seems to store the start_time as a DWORD and uses atoi to parse the wait time, and uses ss_time (which seems only get
> > the time to the nearest second) to fetch the time.
> 
> No it's not implemented, was just my idea. If it would work for you, I can implement it in the next couple of days.
> 
> Stefan

Yes, please!  Something like WAIT seconds, 0.01 would be perfect.

While I will do it, i'm not sure if this is what you want. If I understand correctly, some process gets triggered and then writes some values to the ODB, then the sequencer 
should continue. Putting a wait there is dangerous. Maybe your process always takes like 10-20 ms, so you put a wait of let's say 100ms, and things are fine with you. Your 
script runs many days, but then once in a while your machine is on heavy load because someone starts a web browser, and your process takes 110ms, and you script crashes.

I would rather go following path: put a "done" flag in the ODB, which is the last one which gets set by your process. Then the sequencer does a 

WAIT ODBvalue, /path/value, =, 1

which will work always, independend of the delay of your process.

Stefan

> While I will do it, i'm not sure if this is what you want. If I understand correctly, some process gets triggered and then writes some values to the ODB, then the sequencer 
> should continue. Putting a wait there is dangerous. Maybe your process always takes like 10-20 ms, so you put a wait of let's say 100ms, and things are fine with you. Your 
> script runs many days, but then once in a while your machine is on heavy load because someone starts a web browser, and your process takes 110ms, and you script crashes.
> 
> I would rather go following path: put a "done" flag in the ODB, which is the last one which gets set by your process. Then the sequencer does a 
> 
> WAIT ODBvalue, /path/value, =, 1
> 
> which will work always, independend of the delay of your process.
> 
> Stefan

Our use case is pretty simple and I don't think is affected by the scenario you envision.  We want to turn on a setting in our equipment, and turn it off again some 0.2 s later.  We don't need msec timing.  So something like:

ODBSET /somekey 1   # this will cause a front-end to flip a bit in our hardware     
WAIT seconds, 0.2
ODBSET /somekey 0   # this will cause a front-end to reset a bit in our hardware 

It is true that if the load is high there could be a little delay, and the time that the bit is set will not be 0.2 seconds, but on average it should work, 
and it should be good enough we think.

Yes, we could also check an ODB key to see that something is done, but we'd still need the ability to wait for time intervals less than 1 second, which
right now doesn't exist.

Ok, I implemented the float second wait function. Internally it works in ms, so the maximum resolution is 0.001 s.

Best,
Stefan

> 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).

> > 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

Indeed there was a sleep(100ms) in the sequencer in each loop. I reduced it now to 10ms. I need at least 10ms since otherwise 
the sequencer would run in an infinite loop during the wait and burn 100% CPU. The smallest time slice on Linux to sleep is 
10ms, so that's why I set it to that. Give it a try.

Stefan

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

Stefan

> 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

Dear beloved MIDAS users,

I'm happy to announce a "holiday update" for MIDAS. In countless hours, Zaher from 
PSI worked hard to introduce syntax highlighting in the midas script editor. In 
addition, there are additional features like a cleaner user interface, the option 
to see all variables also in non-debug mode and more. Have a look at the picture 
below, doesn't it beginning to look a lot like Christmas?

We have tested this quite a bit and went through many iterations, but no guarantee 
that it's flawless. So please report any issue here.

I wish you all a happy holiday season,
Stefan

Hi Stefan and Zaher,

there is a problem with the new sequencer interface for midas.

If I understand the msequencer code correctly:
Under '/Sequencer/State/Path' the path can be defined from where the msequencer gets the files, generates the xml, etc.
However, the new javascript code reads/writes the files to '<exp>/userfiles/sequencer/'

If the path in the ODB is different to '<exp>/userfiles/sequencer/', it leads to quite some unexpected behavior. If '<exp>/userfiles/sequencer/' is the place where things should go, the ODB entry of the msequencer and the internal handling should probably adopted, no?

Andreas

> Dear beloved MIDAS users,
> 
> I'm happy to announce a "holiday update" for MIDAS. In countless hours, Zaher from 
> PSI worked hard to introduce syntax highlighting in the midas script editor. In 
> addition, there are additional features like a cleaner user interface, the option 
> to see all variables also in non-debug mode and more. Have a look at the picture 
> below, doesn't it beginning to look a lot like Christmas?
> 
> We have tested this quite a bit and went through many iterations, but no guarantee 
> that it's flawless. So please report any issue here.
> 
> I wish you all a happy holiday season,
> Stefan

> If I understand the msequencer code correctly:
> Under '/Sequencer/State/Path' the path can be defined from where the msequencer gets the files, generates the xml, etc.
> However, the new javascript code reads/writes the files to '<exp>/userfiles/sequencer/'
> 
> If the path in the ODB is different to '<exp>/userfiles/sequencer/', it leads to quite some unexpected behavior. If '<exp>/userfiles/sequencer/' is the place where things should go, the ODB entry of the msequencer and the internal handling should probably adopted, no?

Indeed there is a change in philosophy. Previously, /Sequencer/State/Path could point anywhere in the file system. This was considered a security problem, since one could access system files under /etc for example via the midas interface. When the new file API was 
introduced recently, it has therefor been decided that all files accessible remotely should reside under <exp>/userfiles. If an experiment needs some files outside of that directory, the experiment could define some symbolic link, but that's then in the responsibility of 
the experiment. 

To resolve now the issue between the sequencer path and the userfiles, we have different options, and I would like to get some feedback from the community, since *all experiments* have to do that change.

1) Leave thins as they are, but explain that everybody should modify /Sequencer/Stat/Path to some subdirectory of <exp>/userfiles/sequencer

2) Drop /Sequencer/State/Path completely and "hard-wire" it to <exp>/usefiles/sequencer

3) Make /Sequencer/State/Path relative to <exp>/userfiles. Like if /Sequencer/State/Path=test would then result to a final directory <exp>/userfiles/sequencer/test

I'm kind of tempted to go with 3), since this allows the experiment to define different subdirectories under <exp>/userfiles/sequencer/... depending on the situation of the experiment.

Best,
Stefan

> > If I understand the msequencer code correctly:
> > Under '/Sequencer/State/Path' the path can be defined from where the msequencer gets the files, generates the xml, etc.
> > However, the new javascript code reads/writes the files to '<exp>/userfiles/sequencer/'
> > 
> > If the path in the ODB is different to '<exp>/userfiles/sequencer/', it leads to quite some unexpected behavior. If '<exp>/userfiles/sequencer/' is the place where things should go, the ODB entry of the msequencer and the internal handling should probably adopted, no?
> 
> Indeed there is a change in philosophy. Previously, /Sequencer/State/Path could point anywhere in the file system. This was considered a security problem, since one could access system files under /etc for example via the midas interface. When the new file API was 
> introduced recently, it has therefor been decided that all files accessible remotely should reside under <exp>/userfiles. If an experiment needs some files outside of that directory, the experiment could define some symbolic link, but that's then in the responsibility of 
> the experiment. 
> 
> To resolve now the issue between the sequencer path and the userfiles, we have different options, and I would like to get some feedback from the community, since *all experiments* have to do that change.
> 
> 1) Leave thins as they are, but explain that everybody should modify /Sequencer/Stat/Path to some subdirectory of <exp>/userfiles/sequencer
> 
> 2) Drop /Sequencer/State/Path completely and "hard-wire" it to <exp>/usefiles/sequencer
> 
> 3) Make /Sequencer/State/Path relative to <exp>/userfiles. Like if /Sequencer/State/Path=test would then result to a final directory <exp>/userfiles/sequencer/test
> 
> I'm kind of tempted to go with 3), since this allows the experiment to define different subdirectories under <exp>/userfiles/sequencer/... depending on the situation of the experiment.
> 
> Best,
> Stefan

For me the option 3) seems the most coherent one.
Andreas

> > 3) Make /Sequencer/State/Path relative to <exp>/userfiles. Like if /Sequencer/State/Path=test would then result to a final directory <exp>/userfiles/sequencer/test
> > 
> > I'm kind of tempted to go with 3), since this allows the experiment to define different subdirectories under <exp>/userfiles/sequencer/... depending on the situation of the experiment.
> > 
> > Best,
> > Stefan
> 
> For me the option 3) seems the most coherent one.
> Andreas

Ok, I implemented option 3) above. This means everybody using the midas sequencer has to change /Sequencer/State/Path to an empty string and move the 
sequencer files under <exp>/userfiles/sequencer as a starting point. I tested most thing, including the INCLUDE statements, but there could still be
a bug here or there, so please give it a try and report any issue to me.

Best,
Stefan