A system for asynchronous reads of old data blocks updated through a write-back cache includes a storage device, a write-back cache, a storage consumer, a storage processing node, and device management software. The system searches a database of digital content based on the one or more words and retrieves from the database one or more digital content items or identifiers of digital content items that are related to the one or more words. In a bi-directional embodiment, an operable flow range of the compressor can be widened in both directions of a compressor map, i. The carrier boxes are thrown with loads at the transfer portion, and are delivered by the chain conveyer and discharges the loads at a predetermined location according to the loads.