Abstract: In a multitasking data processing apparatus including means for executing processes and including a display adapter for executing functions supporting a display, the display adapter including a first port means for receiving, from the means for executing processes, requests to execute selected functions having a first execution priority, a second port means for concurrently receiving, from the means for executing processes, requests to execute selected functions having a second execution priority lower than the first execution priority, and means, coupled to the first and second port means, for executing selected functions according to the execution priority.