> Stefan, to avoid confusion from crashes caused by incompatible ODBs would it be possible to add a "version number" to ODB,
together with a check and an error message 
> saying "oops... incompatible ODB, please rebuild your programs"? We tend to have different versions of midas floating around and
users have old executables stashed away, 
> and all this makes it rather difficult to manually keep track on what ODB is compatible with what midas.

I fully agree that a version number in ODB is a good thing, and I certainly will put one there, but this won't help for old
applications. If I add new code which checks in cm_connect_experiment() if the version number matches, this will only help for new
applications connecting to old ODBs. If old applications (prior to invention of the version number) connect to a new ODB, they still
will crash.

However, we are planning to make a new release 1.9.5 soon (next week), so can can people tell not to "mix" 1.9.5 with pre-1.9.5
programs.

> Right. We cannot fix the past, but we should fix the future. BTW, "do not mix versions" is hard to enforce and mismatches did, do and
> will happen

For remote connections (through mserver), there is already a version check. If the minor version differs, you get a warning, if the major
versions differ (1.>>9<<.4), the client won't start. So at least for remote connection you get a clue.

> For one thing, looking at a given midas-using executable, how do I tell what version of midas it has inside?

Ther is a function cm_get_version() returning the version. As for the executable, all you can do is a

strings <executable> | grep 1.9

Can you attach 

/twist/data_onl/current/run17548.odb

so I can reproduce the problem?

> odbedit command "rename Display xxx/yyy" creates a key named "xxx/yyy" (yes,
> with a slash in the name) and this key cannot be deleted or renamed...
> K.O.

"rename" is "rename", not "mv" under Unix. If you want this functionality, put it
in and don't complain!

> We have al_trigger_alarm(), but no matching al_clear_alarm(), and I need it to
> clear my alarm once the alarm condition no longer exists. Any objections if I
> add this function? K.O.

The idea is that once an alarm got triggered, it stays until the user
acknowledged, even if the alarm condition has been disappeared. Through mhttpd,
the user can press the "Reset" button, which then executes al_reset_alarm().
However, it is possible to call al_reset_alarm() directly from user code to
achieve the same thing.

Agree.

Once you did the modification, please check following situation: Create a fresh
ODB withe increased size ("odbedit -s 2000000" for example). Then check that the
other clients "adopt" this increased size. Note that some experiments need a
bigger ODB, and I don't want to have them recompile all clients, that's why the
code in ss_shm_open() can attach to a *larger* shared memory. However, it should
not matter to the process, since the ODB (or SYSTEM) shared memory size is
stored in the pheader->key_size and pheader->data_size of each participating
process. So they should never write beyond the limits defined in that header.
The size to ss_shm_open() is only a "hint" if the shared memory does not exist,
and is nowhere later used in the code.

Hi Jan,

I usually keep under /Experiment/Run Parameters only those settings which are kind of "global" and thus of
interest to frontend *and* analyzer, like a run mode (data/calibration/cosmic/...). Settings more specific to a
frontend I keep under /Equipment/<name>/Settings where <name> is the equipment name the specific frontend
produces. In your case each frontend will then get its own tree (related to each fragment). Please note that
both discussed trees can contain a whole tree with subdirectories, which lets you organize your data better.

Best regards, Stefan.

> - system.c: do not chdir("/") in ss_daemon_init()- it prevents us from ever
>   getting core dumps from midas daemons. The old behaviour is trivially
>   restored by "cd /" before starting the daemon; or by "limit coredumpsize 0".

The chdir("/") is from one of the unix text books. They say you HAVE to do it. If you start a
daemon on an NFS file system, you cannot unmount that file system as long as the daemon is
running. I'm sure the same code is inside most other daemons (apache, ...). So if we go away
from that standard, we have to be aware of the consequences.

> What is the api call to determine the index of the frontend when specifying the
> -i parameter during execution of the frontend? 

INT get_frontend_index();

- Stefan

> Could someone please explain to me how cm_msg, cm_msg1, etc. all work.  The
> documentation is very terse.  
> 
> I want to setup a fairly significant set of debugging, and error messages for a
> new frontend.  I need to get these messages to a logging file.  I also would
> like to get the error messages to the user through whatever interface Midas
> normally uses for error reporting.  

For errors, use

  cm_msg(MERROR, "routine_name", "Your error message, code=%d", i);

This produces an error message which is logged to midas.log, and distributed to all
clients which have called cm_msg_register(). For example odbedit will just print
that message. The syntax of the second half of cm_msg is the same as for printf(),
so you can add format specifiers and variable arguments as you do for printf(). The
first argument is the message type (MDEBUG for example is only distributed but not
logged). 

For a more detailed list of message types, please refer to

http://midas.triumf.ca/doc/html/AppendixE.html#midas_macro

Dealing with the NaN's in the history system in the past week, a question came
up at PSI about how to deal with invalid history data.

Assume you have several devices going into one history equipment, and one device
has a problem, such that it cannot be read. In the past, the device driver
system returned zero, which was written to the history file. While this is ok in
some cases, it might not be in others, where zero is maybe a valid measurement.
Furthermore, it might confuse some regulations loops.

An alternative is to keep the last correctly measured value. As long as the
device has its problem, the value is kept. However, values are written to the
history system which might look like valid, although they are not. So what about
writing explicitly NaNs to the history system? For the display routine the NaNs
could be omitted, leaving blank regions where no valid measurement is available.
Or one could explicitly mare the region as invalid. Konstantin, do you know how
to write NaN explicitly to a float variable? And what do the others think about
these possibilities?

- Stefan

I preliminary implemented NaNs into the history system. It works such that if a
device driver returns a read error status, the class driver writes a NaN
(Not-a-Number) into the corresponding variable via the new function ss_nan(). The
"mhist" utility directly displays these as "nan" (Linux) or "-1.#IND00" under
Windows, indicating the error status. The history display via mhttpd just skips
these values (see elog:/1). I think this is better than showing just zero values,
because in most cases zero is a valid measurement and could confuse people.

Of course it is not enough just having "gaps" in the history display, so it's
important that the corresponding device driver issues an error message, which could
even trigger an alarm.

I have tested this under Windows, but only compiled under Linux. The only class
driver I modified so far is "multi.c". People should have a look, make some tests,
and let me know if this is a good thing, or if we should change it somehow.

- Stefan

> I can't get onto cvs@midas.psi.ch right now
> (cvs update
> cvs@midas.psi.ch's password: 
> Permission denied, please try again.)

I had to upgrade midas.psi.ch today with Scientific Linux 3.03. Most things are back to work, but
 I failed to do the anonymous CVS account. I have to wait for next week when the experts are
there. I will let you know when it's working again.

- Stefan

> > I can't get onto cvs@midas.psi.ch right now
> > (cvs update
> > cvs@midas.psi.ch's password: 
> > Permission denied, please try again.)

cvs@midas.psi.ch should be up and running again.

> is there a reason why histograms are not saved after a replay?
> 
>    /* save histos if requested */
>    if (out_info.histo_dump && clp.online) {
>                               ^^^^^^^^^^
> 
> perhaps the && should be ||?

The original reason for that is the for running online, you want some histos for
monitoring after each run. For running offline, you specify a root output file via
"-o xxx.root" which contains trees AND histos. So the histos would there be twice
if you remove the "clp.online" from above.

Having "-o xxx.root" is IMHO a cleaner way, since you might want to analyze a run
in different ways (like using different calibrations). So what you do is specify
different "-o cal00123.root", "-o final00123.root" and so on, while with the
mechanism in eor() you always get the same file name. So try using "-o xxx.root"
and see if that fits your needs.

Dear Midas users,

may I kindly invite you present your work at the Real-Time 2005 Conference in
Stockholm, June 4-10. The conference deals with all kinds of real time
applications like DAQ, control systems etc. It is a small conference with no
paralles sessions, and with two interesting short courses. The deadline has been
prolonged until March 13, 2005. If you are interested, please register under

http://www.physto.se/RT2005/

Here is the official letter from the chairman:

=====================================================================
               14th IEEE-NPSS Real Time Conference 2005
                  Stockholm, Sweden, 4-10 June, 2005
              Conference web site: www.physto.se/RT2005/

**********************************************************************
*                                                                    *
*        ABSTRACT SUBMISSION PROLONGED! DEADLINE: March 13, 2005     *
*                                                                    *
**********************************************************************

Considering that the Real Time conference is a highly meritorious and
multidisciplinary conference with purely plenary sessions and that the
accepted papers may be submitted to a special issue of the IEEE
Transactions on Nuclear Science we would like to give more people the
opportunity to participate. Therefore we have organized the program so
that there is now more time for talks than at the RT2003 and we are
extending the abstract submission to March 13. We strongly encourage
you to participate!

Submit your abstract and a summary through the conference web site
"Abstract submission" link. Please, make sure that your colleagues know
about the conference and invite them.

I would also like to take this opportunity to announce the two short
courses we have organized for Sunday 5/6:

- "Gigabit Networking for Data Acquisition Systems - A practical
introduction"
  Artur Barczyk, CERN

- "System On Programmable Chip - A design tutorial"
  Marco Riccioli, Xilinx

Please find the abstracts and more information about the conference on
www.physto.se/RT2005/

Thank you if you have already submitted an abstract.

Richard Jacobsson
General Chairman, RT2005 Conference

Email: RT2005@cern.ch
Phone: +41-22-767 36 19
Fax:   +41-22-767 94 25
CERN Meyrin
1211 Geneva 23
Switzerland

Dear midas users,

I have changed the ODB dump format to XML. As you might know, the logger writes
a special begin-of-run event to the .mid file which includes an ASCII dump of
the ODB. The same at the end-of-run. To read these ODB dumps back in offline
analysis, this requires setting up a ODB just to read back these values. In
order to avoid this, we switched the format to XML instead of the old ASCII
format. That way ROME can read the ODB dump and extract individual values from
it without setting up a shared memory.

A similar thing has been made for the ODB dumps to separate .odb files, which
are controlled by "/Logger/ODB Dump" and "/Logger/ODB Dump file". If the dump
file has the extension .xml, the file is dumped in XML format as well.

All the XML functionality is implemented in the new mxml.c/h library, which has
been added to the distribution, and which can be used in other projects as well
(XML configuration of ROODY?). It has already been successfully implemented in
ROME, so ROME is no longer dependent on libxml.

- Stefan

> All the XML functionality is implemented in the new mxml.c/h library, which has
> been added to the distribution, and which can be used in other projects as well
> (XML configuration of ROODY?). It has already been successfully implemented in
> ROME, so ROME is no longer dependent on libxml.

Since mxml.c/h is used in several projects (midas, ROME, elog), I separated it's
CVS tree. So in order to compile midas from scratch, you have to check out midas
AND mxml like

cd ~
cvs -d :ext:cvs@midas.psi.ch:/usr/local/cvsroot checkout midas
cvs -d :ext:cvs@midas.psi.ch:/usr/local/cvsroot checkout mxml

cd midas
make

so the "mxml" tree is ABOVE the "midas" tree. The midas Makefile has been adjusted
accordingly. If you decide to put the mxml somwhere else, you have to change
MXML_DIR in the Makefile accordingly.

- Stefan

> Looks like the midas mxml Makefile bits did not make it to CVS. Current Makefile
> revision 1.67 does not have them and building midas from cvs sources fails because it
> does not find mxml.h and mxml.c

I forgot to commit the new Makefile, thanks for reminding me. Now it should be fine.

> Current MIDAS versions nag me about setting the env.variable MIDASSYS to the
> "midas installation directory", but I do not have one, so what should I set
> MIDASSYS to? I checkout MIDAS from cvs into /home/olchansk/daq/midas, build it
> there, run it from there. I never do "make install" (I am not "root" on every
> machine; I am not the only MIDAS user on every machine). What should I set
> MIDASSYS to? K.O.

Then set it to /home/olchansk/daq/midas. The reason for MIDASSYS is the same as
for ROOTSYS. Having it allows other packages like ROME to access the Midas source
code, include files and libraries.