> The way connections work under Midas is there is a callback scheme. The client starts 
> mserver on the back-end, then the back-end connects back to the front-end on three 
> different ports. These ports are assigned dynamically by the operating system and are 
> typically in the range 40000-60000. So you also have to allow the reverse connection on 
> your firewalls.

It works now after allowing ports 40000-60000 in the front-end computer. Thanks!

Best Regards,
Jimmy

> > The way connections work under Midas is there is a callback scheme. The client starts 
> > mserver on the back-end, then the back-end connects back to the front-end on three 
> > different ports. These ports are assigned dynamically by the operating system and are 
> > typically in the range 40000-60000. So you also have to allow the reverse connection on 
> > your firewalls.
> 
> It works now after allowing ports 40000-60000 in the front-end computer. Thanks!


Yes, right. Midas networking does not like firewalls.

In the nutshell, TCP connections on all TCP ports have to be open between all computers
running MIDAS. I think in practice it is not a problem: you only ever have a finite (a small
integer) number of computers running MIDAS and you can be added them as exceptions to the
firewall rules. These exceptions should not create any security problem because you still have
the MIDAS computers firewalled from the outside world and one hopes that they will not be
attacking each other.

P.S. Permitting ports 40000-60000 is not good enough. TCP ports are allocated to TCP
connections semi-randomly from a 16-bit address space (0..65535) and your system will bomb
whenever port numbers like 39999 or 60001 get used.


K.O.

Reading an FADC buffer often needs large buffer size, especially while several
FADCs work together. I want to know how large a bank32 can support.

> Reading an FADC buffer often needs large buffer size, especially while several
> FADCs work together. I want to know how large a bank32 can support.

The "32" in bank32 means 32-bits, so the bank holds 2^32=4 GBytes, hope that is enough for your ADC. 
The "normal" bank has only a 16-bit header, so it can hold only 64 kBytes. But for small banks, the overhead 
is therefore smaller.

I'm brand new to MIDAS, and C system programming in general, so please be
gentle. I've compiled and installed MIDAS 2.3.0 on Ubuntu 10.04 LTS. I've built
the kernel driver, khyt1331.ko and installed it. It appears to be working, since
the camactest and esonetest programs included with the driver work just fine.

So I attempted to build the example experiment distributed with MIDAS, with the
following changes to the Makefile:

DRV_DIR   = $(MIDASSYS)/drivers/kernel/khyt1331_26

and

DRIVER = camac

The programs build without error but when I try to start the frontend, I get:

$ ./frontend
Frontend name          :     CSM-Nuclear Portable DAQ Frontend
Event buffer size      :     1000000
User max event size    :     10000
User max frag. size    :     5242880
# of events per buffer :     100

Connect to experiment...
*** buffer overflow detected ***: ./frontend terminated
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6(__fortify_fail+0x50)[0x6de390]
/lib/tls/i686/cmov/libc.so.6(+0xe12ca)[0x6dd2ca]
/lib/tls/i686/cmov/libc.so.6(__strcpy_chk+0x44)[0x6dc644]
./frontend[0x805611f]
./frontend[0x806f656]
./frontend[0x8053d82]
/lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe6)[0x612bd6]
./frontend[0x804bb81]
======= Memory map: ========
00110000-0012d000 r-xp 00000000 08:05 7471187    /lib/libgcc_s.so.1
0012d000-0012e000 r--p 0001c000 08:05 7471187    /lib/libgcc_s.so.1
0012e000-0012f000 rw-p 0001d000 08:05 7471187    /lib/libgcc_s.so.1
00264000-00277000 r-xp 00000000 08:05 7603242    /lib/tls/i686/cmov/libnsl-2.11.1.so
00277000-00278000 r--p 00012000 08:05 7603242    /lib/tls/i686/cmov/libnsl-2.11.1.so
00278000-00279000 rw-p 00013000 08:05 7603242    /lib/tls/i686/cmov/libnsl-2.11.1.so
00279000-0027b000 rw-p 00000000 00:00 0 
002db000-002dd000 r-xp 00000000 08:05 7603265   
/lib/tls/i686/cmov/libutil-2.11.1.so
002dd000-002de000 r--p 00001000 08:05 7603265   
/lib/tls/i686/cmov/libutil-2.11.1.so
002de000-002df000 rw-p 00002000 08:05 7603265   
/lib/tls/i686/cmov/libutil-2.11.1.so
003b1000-003c6000 r-xp 00000000 08:05 7603257   
/lib/tls/i686/cmov/libpthread-2.11.1.so
003c6000-003c7000 r--p 00014000 08:05 7603257   
/lib/tls/i686/cmov/libpthread-2.11.1.so
003c7000-003c8000 rw-p 00015000 08:05 7603257   
/lib/tls/i686/cmov/libpthread-2.11.1.so
003c8000-003ca000 rw-p 00000000 00:00 0 
004ea000-004f1000 r-xp 00000000 08:05 7603261    /lib/tls/i686/cmov/librt-2.11.1.so
004f1000-004f2000 r--p 00006000 08:05 7603261    /lib/tls/i686/cmov/librt-2.11.1.so
004f2000-004f3000 rw-p 00007000 08:05 7603261    /lib/tls/i686/cmov/librt-2.11.1.so
005fb000-005fc000 r-xp 00000000 00:00 0          [vdso]
005fc000-0074f000 r-xp 00000000 08:05 7603231    /lib/tls/i686/cmov/libc-2.11.1.so
0074f000-00750000 ---p 00153000 08:05 7603231    /lib/tls/i686/cmov/libc-2.11.1.so
00750000-00752000 r--p 00153000 08:05 7603231    /lib/tls/i686/cmov/libc-2.11.1.so
00752000-00753000 rw-p 00155000 08:05 7603231    /lib/tls/i686/cmov/libc-2.11.1.so
00753000-00756000 rw-p 00000000 00:00 0 
00783000-00796000 r-xp 00000000 08:05 7471302    /lib/libz.so.1.2.3.3
00796000-00797000 r--p 00012000 08:05 7471302    /lib/libz.so.1.2.3.3
00797000-00798000 rw-p 00013000 08:05 7471302    /lib/libz.so.1.2.3.3
008ab000-008c6000 r-xp 00000000 08:05 7471129    /lib/ld-2.11.1.so
008c6000-008c7000 r--p 0001a000 08:05 7471129    /lib/ld-2.11.1.so
008c7000-008c8000 rw-p 0001b000 08:05 7471129    /lib/ld-2.11.1.so
008e4000-00908000 r-xp 00000000 08:05 7603239    /lib/tls/i686/cmov/libm-2.11.1.so
00908000-00909000 r--p 00023000 08:05 7603239    /lib/tls/i686/cmov/libm-2.11.1.so
00909000-0090a000 rw-p 00024000 08:05 7603239    /lib/tls/i686/cmov/libm-2.11.1.so
08048000-0809d000 r-xp 00000000 08:11 20318114   /home/midas/online/test/frontend
0809d000-0809e000 r--p 00055000 08:11 20318114   /home/midas/online/test/frontend
0809e000-080a3000 rw-p 00056000 08:11 20318114   /home/midas/online/test/frontend
080a3000-080c5000 rw-p 00000000 00:00 0 
0835f000-08380000 rw-p 00000000 00:00 0          [heap]
b7881000-b7884000 rw-p 00000000 00:00 0 
b7893000-b7895000 rw-p 00000000 00:00 0 
bf938000-bf94d000 rw-p 00000000 00:00 0          [stack]
Aborted

Please help me figure out what's going wrong!

Thank you,
Jon

> Reading an FADC buffer often needs large buffer size, especially while several
> FADCs work together. I want to know how large a bank32 can support.

Limitations in order:

- bank32 size is limited to a 32 bit integer size (about 4000 Gbytes)
- bank size is limited by event size
- event size in a midas mfe.c based frontend is limited to the value of
max_event_size set by the user
- maximum event size that can go through the MIDAS event buffer system is limited
to ODB value /Experiment/MAX_EVENT_SIZE (MAX_EVENT_SIZE in midas.h does not do
anything now)
- maximum event size is limited to *half* the size of the SYSTEM shared memory
event buffer (or any other buffers that the event has to go through)
- default size of the SYSTEM buffer is 8 Mbytes set by ODB /Experiment/Buffer
sizes/SYSTEM. This limits maximum event size to about 4 Mbytes.
- size of SYSTEM buffer can be increased to arbitrary size, but in practice no
bigger than the amount of computer physical memory minus space needed for running
the frontend program and the mlogger, which also allocate buffer space to hold 1
event of maximum size.

So for a computer with 8 Gbytes of RAM, you can make the SYSTEM buffer size 4
GBytes, set ODB MAX_EVENT_SIZE to 1 Gbyte, and in theory, you should be able to
write 1 Gbyte events from your frontend to disk.

In practice, I think the biggest events I have seen go through a MIDAS system are
non-compressed waveforms in the T2K/ND280 FGD and TPC detectors, about 4 Mbytes of
data per event.

Other considerations (rules of thumb):

1) the SYSTEM event buffer should be big enough to hold 10-100 events.
2) the SYSTEM event buffer should be big enough to hold about 5-10 seconds of data
- i.e. if your event size is 1 Mbyte and data rate is 1 Hz, 10 seconds of data
will be 1Mbyte*1Hz*10sec = 10 Mbytes.

This is because the SYSTEM buffer decouples the real-time activity of the frontend
program from non-real-time activity of writing data to storage devices.

K.O.

Dear All,

I got a "Cannot open input file" error when I tried to analyze a .mid.gz file with 
size over 5 GB on a 32-bit Linux. The error traced back to gzopen() in mana.c 
where it returned NULL when opening the file. I understand that 32-bit Linux may 
not be able to handle files with size over 2 GB. I tried to add -
D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 to CFLAGS in the Makefile of MIDAS and 
the analyzer, but I still got the same error. Is there any workarounds that enable 
me to analyze large files on 32-bit systems?

p.s. The data file was also produced on a 32-bit Linux.

Thanks & Best Regards,

Jimmy

The HTTPS SSL certificate on ladd00.triumf.ca has been updated. Same as the old
certificate, the new one is self-signed and your web browser may complain about
that and ask you to "save a security exception".

When you save the new certificate, you can verify that you are connected to the
real ladd00.triumf.ca by comparing the "SHA1 fingerprint" reported by your web
browser to the one given below (as reported by "svn update"):

Certificate information:
 - Hostname: ladd00.triumf.ca
 - Valid: from Jun 17 23:36:35 2011 GMT until Jun 16 23:36:35 2012 GMT
 - Issuer: DAQ, TRIUMF, Vancouver, BC, CA
 - Fingerprint: 2a:be:9f:9f:70:d4:dc:72:9f:63:bf:4f:fe:c0:2c:8f:a8:29:f2:f1

K.O.

Dear All,

Thanks Konstantin Olchanski for providing me a hint. The file can be opened now after I 
changed the line: 

file->gzfile = gzopen(file_name, "rb");

in function ma_open() in mana.c to the followings: 

INT fd = open(file_name, O_RDONLY | O_LARGEFILE);
if (fd <= 0)
   return NULL;

file->gzfile = gzdopen(fd, "rb");

No modifications to the Makefile is needed in this case.

Best Regards,
Jimmy


> Dear All,
> 
> I got a "Cannot open input file" error when I tried to analyze a .mid.gz file with 
> size over 5 GB on a 32-bit Linux. The error traced back to gzopen() in mana.c 
> where it returned NULL when opening the file. I understand that 32-bit Linux may 
> not be able to handle files with size over 2 GB. I tried to add -
> D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 to CFLAGS in the Makefile of MIDAS and 
> the analyzer, but I still got the same error. Is there any workarounds that enable 
> me to analyze large files on 32-bit systems?
> 
> p.s. The data file was also produced on a 32-bit Linux.
> 
> Thanks & Best Regards,
> 
> Jimmy

Hi,

I've been doing some preliminary work to use at least the MIDAS
SQL history component for a new CERN experiment (Aegis). I wonder
whether there is any plan to support 64-bit signed/unsigned integer data types
in MIDAS. time_t on 64-bit architectures is actually signed 64-bit
(the 'easy' way to work around the 2038 crisis), and this may be enough to
cause problems.

Thanks.
Francesco Prelz
INFN Milano

Hello,
      I'm trying to build khyt1331 under scientific linux 5.5, kernel
2.6.18-238.9.1el5.  Has anyone succeeded with this.  So far, I've
managed to compile by hacking all the references to man9 pages out
of the makefile.  I've then hand installed the kernel driver with 
insmod.  cat /proc/khyt1331 produces 
Hytec 5331 card found at address 0xE800, using interrupt 10
Device not in use
CAMAC crate 0: responding
CAMAC crate 1: not responding
CAMAC crate 2: not responding
CAMAC crate 3: not responding 
and the "addr" LED blinks - so progress of some sort.  
There's no sign of /dev/camac.

Next up I'm going to compile stuff like camactest.c - though the 
makefiles in the drivers folder don't mention these, so I'll have to
work through what is needed by hand.   

At some point I'll have to rewrite a bit so that it all load automatically.

Any hints or tips greatfully received.

John McMillan

The HTTPS SSL certificate on ladd00.triumf.ca has been updated. Same as the old
certificate, the new one is self-signed and your web browser may complain about
that and ask you to "save a security exception".

When you save the new certificate, you can verify that you are connected to the
real ladd00.triumf.ca by comparing the "SHA1 fingerprint" reported by your web
browser to the one given below (as reported by "svn update"):

Certificate information:
 - Hostname: ladd00.triumf.ca
 - Valid: from Wed, 13 Jun 2012 22:31:51 GMT until Thu, 13 Jun 2013 22:31:51 GMT
 - Issuer: DAQ, TRIUMF, Vancouver, BC, CA
 - Fingerprint: 82:95:78:cb:78:d3:93:1d:d4:c8:e8:1a:64:0f:62:04:2d:0e:c3:4a

K.O.

Hello all,

I am trying to put together a system to read out several camac adc. The camac is
read by a ces8210 camac to vme controller. The vme is then interfaced to a
computer through a CAEN v1718 usb control module. As anyone gotten the latter to
work?

Previous users seemed to indicate that they had here:

https://ladd00.triumf.ca/elog/Midas/493

but I am having problems to get this example frontend to compile. What is set as
the driver in the makefile for example? If I put v1718 there then I recieve
numerous errors from the CAENVMElib files. 

If someone else has gotten the V1718 running, I would be grateful for their
insight. 

Thanks, 
-Carl