Welcome to the Persistency web

The Persistency Framework is a project providing two software packages (CORAL and COOL) that address the data access requirements of the LHC experiments in several different areas. The project is the result of the collaboration between the CERN IT Department and the three LHC experiments (ATLAS, CMS, LHCb) that are using some or all of the Persistency Framework components to access their data. It is part of the Application Area of the LHC Computing Grid. The Persistency Framework project used to provide also a third package (POOL, which was actually the first one to be developed), but the maintenance and support responsibility for it has now moved to ATLAS (the only experiment that still uses POOL).

• CORAL is an abstraction layer with an SQL-free API to access data stored using relational database technologies. It is used directly by experiment-specific applications and internally by both COOL and POOL.
• COOL provides specific software components and tools for the handling of the time variation and versioning of the experiment conditions data.
• POOL is a hybrid technology store for C++ objects, using a mixture of streaming and relational technologies to implement both object persistency and object metadata catalogs and collections. It provides generic components that can be used by the experiments to store both their event data and their conditions data.

Contents of this TWiki

The Persistency web is structured hierarchically into groups of related topics. One 'parent' topic in each group is the entry point to all its 'child' topics in that group. You may use the menu in the left bar to navigate hierarchically through all topics. The Persistency web contains one topic group for each of the two projects, as well one topic group covering commonalities between the two projects, and one group of configuration utilities and documentation pages for this twiki web:

• Cool
• Coral
• PersistencyCommon
• WebUtilities

Several topics which had been added in the past have become obsolete over the years. While most of these obsolete topics are still in the main twiki pages or have been deleted, a few have been moved to a special section of this twiki, by declaring them as children of the standalone ObsoleteTopics page. If a page in this twiki becomes obsolete, please rename it (so that its name starts with "OLD") and move it to the obsolete section by setting its parent topic to the ObsoleteTopics page. Note that the ObsoleteTopics page has no parent.

External links

A collection of useful links to web pages maintained outside this TWiki have been added at the end of the left bar, where they are marked in italics.

Older web sites

This Twiki, created in June 2010, is meant to replace the three older web sites specific to CORAL, COOL and POOL, as well as the more recent Persistency web site on Drupal, updating and merging into a single web site the vast amount of information that was previously scattered there.

-- AndreaValassi - 02-Oct-2013

Child topics (in alphabetical order): Cool Coral PersistencyCommon TWeederTopics WebUtilities