These software motion video calls let MMPM/2 determine the exact location and size of memory-mapped VRAM. For video adapters with bank-switched VRAM, efficient, device-independent means are provided to safely gain access to the VRAM resources, manipulate the bank switch mechanism, and release the adapter. This architecture follows the same rationale as WIN-OS/2 seamless windows, using the same mechanisms to ensure reliable sharing of the device.