Loading old Physics Data Files - Part 2

Previously, my attempt at running a FORTRAN program to load my old ZEUS data ntuples failed because CERNLIB isn't compatible with a 64-bit Linux OS:

 Test loading ntuple files
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
LOCB/LOCF: address 0x562cca6e2c80 exceeds the 32 bit address space
or is not in the data segments
This may result in program crash or incorrect results
Therefore we will stop here
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 

Unfortunately, the recommendation in  /usr/share/doc/libpacklib1-dev/README.64-bit to statically link didn't work for me:

Static linking is the default behavior if you use the "cernlib" script when
linking, like this:

 # Should work everywhere:
 gfortran -o myprogram myprogram.F `cernlib -G Motif pawlib` 

Fortunately, Linux Mint still provides a 32-bit version of the latest OS. So, at this point rather than trying to fix it in 64-bit I thought the best approach would be to setup a Virtual Machine.

For the VM host, I decided to use VirtualBox. This is easy to install on Ubuntu from the Software Center.

After downloading the 32-bit Linux Mint ISO I setup a new VM with 4MB of Memory and Dynamically Allocated Storage with 70GB Virtual Size.

After installing Mint, I reinstalled the CERNLIB packages from the Mint Software Manager and loaded up the ntuple in PAW as per my last post

Now, given this was working I could try and load the file using my FORTRAN program:

      program main

      implicit none
      integer istat, NEvents, idnt
      real hmem
      common/pawc/hmem(2000000)

      print *, "Test loading ntuple files"
      call hlimit(2000000)  
     
      call hropen(80,'ntuple','mc97_1.rz','',4096,istat)
 
      if (istat.ne.0) then
          print *, "Failed to open input file"
         stop
      endif

      print *, "Loaded mc96_1.rz"
      call hrin(10, 9999999, 0) 
      call hnoent(10,NEvents)
      print *, NEvents
c      print *, idnt    

      call hrend('ntuple')
      close(80)  

      end program main

And this time, success!

 Test loading ntuple files
 Loaded mc96_1.rz
       51781

There's a few points to bear in mind:

• common/pawc/hmem(2000000) is required to reserve locations to a common /PAWC/, for the HBOOK working space (an array)
• call hlimit(2000000) informs HBOOK of the storage limit
• call hropen opens the direct access rz file
• call hrin(10, 9999999, 0) reads a histogram from the current directory of the direct access file into the current directory in memory. The 9999999 to to read the highest cycle
• call hnoent Gets the number of events in the in-memory identifier