The mi2b2 client sends requests to the mi2b2 server, which, in turn, asks the PACS to copy these studies into mi2b2 server's repository (cache). The copying of studies is done via the DICOM C-Move directive, and it is executed asynchronously by the mi2b2 server. Because accessing clinically utilized PACS may impact their performance, mi2b2 is typically configured to only access these PACS during downtime (when volume of clinical use is low). As such, the time it takes to fulfill each request is highly dependent upon the mi2b2 server's configuration, PACS access policy, load, and availability. Once the studies are available in the mi2b2 cache, users can later download them onto their own local machine.