The invention is a modular backup and retrieval system. The software modules making up the backup and retrieval system run independently, and can run either on the same computing devices or on different computing devices. The modular software system coordinates and performs backups of various computing devices communicating to the modules. Actions of modules on one of the computing devices acts as a system manager for a network backup regimen. A management component acts as a manager for the archival and restoration of the computing devices on the network. It manages and allocates library media usage, maintains backup scheduling and levels, and supervises or maintains the archives themselves through pruning or aging policies. The management component is not hard wired in its functionality, but may adapt to changing circumstances in these policies. A second software module acts as a manager for each particular library media.