FlashCopy FlashCopy mapping FlashCopy relationship FlashCopy service Flash drive Flash module Front end and back end Global Mirror Global Mirror with change volumes Grain Hop FlashCopy refers to a point-in-time copy where a virtual copy of a volume is created. The  target volume maintains the contents of the volume at the point in time when the copy was  established. Any subsequent write operations to the source volume are not reflected on the  target volume. A FlashCopy mapping is a continuous space on a direct-access storage volume that is  occupied by or reserved for a particular data set, data space, or file. See FlashCopy mapping. FlashCopy service is a copy service that duplicates the contents of a source volume on a  target volume. In the process, the original contents of the target volume are lost. See also  “Point-in-time copy” on page 808. A data storage device that uses solid-state memory to store persistent data. A modular hardware unit that contains flash memory, one or more flash controllers, and  associated electronics. The SVC takes MDisks to create pools of capacity from which volumes are created and  presented to application servers (hosts). The volumes that are presented to the hosts are in  the front end of the SVC.  Global Mirror (GM) is a method of asynchronous replication that maintains data consistency  across multiple volumes within or across multiple systems. Global Mirror is generally used  where distances between the source site and target site cause increased latency beyond  what the application can accept. Change volumes are used to record changes to the primary and secondary volumes of a  remote copy relationship. A FlashCopy mapping exists between a primary and its change  volume, and a secondary and its change volume.  A grain is the unit of data that is represented by a single bit in a FlashCopy bitmap (64 KiB or  256 KiB) in the SVC. A grain is also the unit to extend the real size of a thin-provisioned  volume (32 KiB, 64 KiB, 128 KiB, or 256 KiB). One segment of a transmission path between adjacent nodes in a routed network. Appendix C. Terminology  803