Configuration, build and distribution of LCG applications area software for the LHC experiments

The Software Process and Infrastructure project (SPI) of the LCG Applications Area (AA) is responsible for a set of services for software build, software packaging, software distribution, communication and quality assurance for LHC experiments. Recently a new tool has been developed in SPI for the automatic build of the LCG/AA software stack which is used for feature and integration testing. The projects being built via this tool are ROOT, SEAL, POOL, CORAL, COOL and RELAX. On top of these also experiment software like GAUDI is built and the build products, being publically available, are further used by experiments for their testing. In addition to testing LCG/AA software the system is also used for the production of software releases. In this talk the design, features and performance of this build system will be presented. Examples for configurations currently in use and their maintenance will be discussed as well as constraints and difficulties in the development of the system (e.g. multi platform, architectures, compilers, configuration tools, performance issues). An outlook to future developments like distributed and parallel builds will be presented. The latter being important to speed up the delivery times for bug fixes of the LCG AA software stack to the user / experiments. This will become more important as we are getting closer to the startup of the LHC. The talk will also describe tools and policies of software packaging and software distribution in the LHC environment. It will be more and more important to be able to distribute the LCG software in an easy and transparent way to the users. The tools in the SPI project which aim to achieve this functionality both for binary distribution and rebuilt of the LCG/AA software from source will be presented.