The Computational Materials Repository

78 Computational Materials Repository3.5.4 CMR in the CloudCloud computing is a service that provides resources such as memory, computinghours, hosting of databases or virtual machines. The name comes from seeingthe components only through the cloud: it is unclear (and unimportant) for thesubscriber what hardware is used and how it is organized exactly. Depending onwhether an institute has its own computing resources and an administrator, itmight be cheaper and more scalable to host the CMR database in the cloud.3.6 ConclusionCMR meets the requirements to provide a framework that is able to aggregate,store, monitor, analyze, present and share data from electronic structure calculations.In order to perform data exchange, a new file format (db-files/cmr-files)was created that does not depend on third-party software and enables long-termdata storage. CMR provides different kinds of user interfaces that enable userswith different expertise to access data: the PHP/HTML user interface providesaccess within a web browser, the Python user interface allows scriptable accessand the command-line interface makes working with db-files easier. The implementationworks out of the box after the installation, is built from well-knownstable components, is held very general and can therefore handle most of thedesired tasks. However, due to the generality it doesn’t work optimally in allsituations. If the constraints for queries get too complicated, then a customarrangement of the involved data in the database is required. This arrangementcould be created with an agent that automatically updates it when new data isadded to the database. (This agent has to be implemented by the user.) TheComputational Materials Repository shows how to solve the problems related tocollection, presentation and analysis of data from electronic structure codes andproofs that it works by providing a working implementation.