====== User Software :: Data Access Library (DAL) ======

==== DAL v2 ====

The new DAL (DAL v2) is available from the same github location as the original DAL: https://github.com/nextgen-astrodata/DAL
It is also used by the LOFAR RTCP beamformer and TBB data writers.
For more information, see the README and INSTALL.


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**The information below refers to the DAL (v1).** Its repository has been moved into https://github.com/nextgen-astrodata/DAL1 but it is no longer maintained.
The LUS still contains DAL v1.


==== Getting the source code (DAL v1) ====

As of Feb 15, 2011 there are two ways in which to retrieve, build and install the
DAL:

  - From the original source repository on Github. \\ In order to build the **DAL** as a stand-alone library, clone directly from the repository on Github: <code bash>
git clone https://github.com/nextgen-astrodata/DAL.git DAL
</code> Once your checkout from the Git repository is complete, follow the instructions as described in the section "Configuration and build" below.
  - As part of the LOFAR User Software (LUS). \\ If you want (or need) to use the DAL as part of the LUS software collection, check out a working copy of the code base from the LUS Subversion repository <code bash>
svn co http://usg.lofar.org/svn/code/trunk lofarsoft
</code> Once the checkout is complete (assuming bash as shell): <code bash>
cd lofarsoft
export LOFARSOFT=`pwd`
. ./devel_common/scripts/init.sh
cd build
./bootstrap
make dal
</code> By default build of the DAL will be carried out from a source tar-archive which comes as part of the software collection.

==== Configuration, build and installation (DAL v1) ====

The DAL uses the CMake (www.cmake.org) Cross-Platform Makefile Generator for 
configuration and control of the build.

Once your checkout from the Git repository is complete you will have a directory
structure on disk as described in section "Organization of the source code"
above.
<code bash>
  cd DAL
  mkdir build
  cd build
  cmake ..
  make
</code>
The default installation location is "/opt/dal"; if you want to change this,
you can tell CMake so by using
<code bash>
  cmake -D DAL_INSTALL_PREFIX=<installation prefix> ..
</code>
The CMake scripts will check a number of standard locations for the required
3-party packages (such as Boost, HDF5, etc.), but if you are using a custom
version installed at a non-standard location, you might need to aid CMake in
finding all required components:
<code bash>
  cmake -DHDF5_ROOT_DIR=<basedir of HDF5 install> ..
</code>
In to install the DAL you will have to run
<code bash>
  make install
</code>
from within the build directory. Depending on whether you are installing into a
local directory or into a system-directory, appropriate permissions might be
required.

In order to maintain compatibility with the Filesystem Hierarchy Standard (FHS)
the following default installation layout has been defined:
<code>
/opt
└── dal                            CMAKE_INSTALL_PREFIX   = DAL_INSTALL_PREFIX
    ├── bin                        DAL_INSTALL_BINDIR     = DAL_INSTALL_PREFIX/bin
    ├── include                    DAL_INSTALL_INCLUDEDIR = DAL_INSTALL_PREFIX/include
    │   ├── coordinates
    │   ├── core
    │   ├── data_common
    │   └── data_hl
    ├── lib                        DAL_INSTALL_LIBDIR     = DAL_INSTALL_PREFIX/lib
    └── share
        └── doc
            └── html
</code>
However the installation configuration can be tailored depending on your personal
needs:

  - //Default settings.// \\ If no further command line parameter are provided, the installation will be done according to the above described structure.
  - //Custom installation prefix.// \\ In order to install into an existing standard directory structure -- such such as e.g. "/usr/local" -- use <code bash>
-D DAL_INSTALL_PREFIX=<prefix>
</code>
  - //Installation as part of the LUS.// \\ In order to simplify installation of the DAL as part of the LOFAR User Software distribution, a preset has been defined which can be used through <code bash>
       -D LUS_INSTALL_PREFIX=$LOFARSOFT/release
</code>

For further details and additional configuration options, consult the Doxygen-based
documentation.

\\
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