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Installing PRECIS


PRECIS runs only under GNU/Linux on a PC.

OpenSUSE Linux 11 is our recommended distribution and will be given out with the PRECIS DVD.

Two Basic Unix/Linux reference guides are are installed with PRECIS (in $UMDIR/docs):

  • LinuxCommandsQuickRef.pdf
  • OnePageLinuxManual.pdf

As well as a more detailed help manual:

  • SUSE.Linux.9.3.eBook.pdf

Look on the Internet for tutorials. A good basic one can be found at http://lowfatlinux.com

Machine Requirements

Choose the fastest system possible, with an Intel or AMD processor capable of running 32 bits natively (this means 64 bit CPUs with 32 bit extensions are OK, but a pure 64 bit CPU is not). Almost all modern day 64 bit CPUs can run 32 bit executables natively.

Dual Core / Quad Core (or more) systems are preferred.

The default installation of PRECIS is not designed to run on distributed memory clusters systems (i.e. cluster or supercomputer systems in which dedicated job control / scheduling / queuing software is present). PRECIS can be made to work on such systems at additional cost (email for details).

At least 512MB memory (1 GB per CPU core is preferred)

Lots of disk space (>500GB)

DVD-ROM drive

UPS (if required)

General Install Requirements

For a system whose main purpose is to run PRECIS, it is recommended to use a a standard 32 bit Linux install, although PRECIS is able to run on 64 bit Linux (as modern 64 bit processors can run 32 bit executables natively).

Required packages:

  • Mozilla or Mozilla Firefox
  • pdksh (public domain Korn Shell, on the PRECIS DVD)
  • xanim (animation in the monitor window, on the PRECIS DVD)
  • gnuplot (for plotting in pptimeseries, on the PRECIS DVD)
  • gv (GhostView, for viewing *.ps postscript files)
  • Imagemagick
  • gawk (Gnu awk)
  • a PDF file viewer such as Acrobat Reader or kpdf
  • a text editor program like Emacs or Pico are helpful

Set up a 'precis' user account during the installation

Disk Layout

Decide on the disk layout.

The default is OK for single disk system.

For dual disk systems, bear in mind the larger directories:

Input data 40GB-300GB (i.e. $PP4LBCDIR)

Work data 5GB (i.e. $DATADIR)

Output data 130GB-540GB depending on output diagnostic options (i.e. $ARCHIVEDIR)

As an example, if you have a 100GB drive and 500GB drive installed in your PC, when installing PRECIS choose the location of the 500GB drive for the larger directories.

Main Installation points

Description of directories:

  • System directories

          /home/precis/um The PRECIS system code. All of the required files are copied to this directory at the end of the installation process.
          /home/precis/precis_out Output directory for PRECIS run time messages

  • Work directories

          /home/precis/precis_expt Directory used by PRECIS when it is running to store control and intermediate files. This includes the current output data files and log files. A directory named $DATADIR/RUNID, where RUNID is the five letter internal PRECIS run ID of the experiment, will be created when PRECIS is run.
          /home/precis/ancil Directory where the processed ancillaries for the selected region are stored. For a given RUNID the ancillaries will be located in $ANCILDIR/RUNID
          /home/precis/lbc Directory where the processed input LBCs are stored. For a given RUNID the LBCs will be located in $LBCDIR/RUNID

  • Input data directories

          /home/precis/ancil/master The global master ancillary files. All of the required files are copied at the end of the installation process.
          /home/precis/pp4lbc The files required to generate the LBCs used by PRECIS. These files have to be obtained from the Met Office. The files required to generate the LBCs for each driving experiment should be placed in their own subdirectory, i.e. the LBCs for GCM with ID addfa should be copied to $PP4LBCDIR/addfa
          /home/precis/dumps Location of the initial PRECIS dumps. These files have to be obtained from the Met Office. All initial dumps should be copied to this directory. Do not use subdirectories.

  • Output directory

          /home/precis/archive Directory into which the output diagnostic files are copied. For a given RUNID the output files will be copied to $ARCHIVEDIR/RUNID

  • Temporary directory

          /home/precis/precis_expt/tmp Directory where the temporary files generated when PRECIS is run are located.

  • Global data directory

          /home/precis/archive/global_data Directory in which the global observational data for analysis purposes is stored.

How to Install

  • Insert the PRECIS DVD 
  • Switch to root/superuser mode
      su - # switch to root/superuser
  • Uninstall the package "ksh" if it is installed (required)
      rpm -e ksh
  • Mount the PRECIS DVD, e.g.:
      mkdir -p /media/dvd
      mount /dev/cdrecorder /media/dvd
  • Install pdksh if not already installed (required)
      rpm -Uvh /media/dvd/utils/pdksh-5.2.14-16.i386.rpm
  • For OpenSUSE 11.4 as distributed at the August 2011 Reading PRECIS workshop, install ATD:
    rpm -Uvh /media/dvd/utils/at-3.1.8-1094.3.1.i586.rpm # 32 bit Linux 
  • Install xanim (optional, for animations) if not already installed
      rpm -Uvh /media/dvd/utils/xanim-2.80.1-7.i386.rpm

            (For Opensuse 11, use:)

      rpm -Uvh /media/dvd/utils/xanim-2.80.1-20.1.i586.for.suse.11.1.rpm
  • Activate the at daemon (atd)

            go to System --> System Services (Runlevel)

            choose atd, click on Enable, Continue, OK, then Finish and Yes

  • Exit from superuser to normal user mode
  • Install PRECIS in user (not superuser!) mode
      cp -v /media/dvd/install_precis $HOME
      cd $HOME
      ./install_precis /media/dvd
  • Choose a three letter prefix for your Runids 
  • Wait while the installation runs
  • Source setvars 

     . ~/setvars
  • (If necessary) Install the sample ERA-15 boundary data from the DVD

      cp -v /media/dvd/install_data $HOME
      cd $HOME
      ./install_data /media/dvd 

Extra Contents on the DVD

In ~/utils on the DVD there are several install packages:

  • pdksh - the korn shell (required)
  • xanim (required for animations)
  • gnuplot
  • ghui/umui for previous users of the Portable UM
  • The statistical package R and Rclimdex
  • pp2netcdf -- convert from PP format to NetCDF format
  • NCL (NCAR Command Language - for NetCDF)  


After the ./install_precis script is complete,

Source setvars (. ~/setvars)

Start PRECIS by typing precis

Run an experiment!

Once you have installed PRECIS and run with the sample boundary data on the DVD, the rest of the boundary data will be supplied on a hard drive (250GB-1TB in size depending on your subregion size) after you have emailed your region file (via Region Tools-->Export) and carried out a test run with your region using the one year of sample driving data on the PRECIS DVD. 

Last Updated: 5 September 2011