Abstract: A method and system for reducing overhead time required to search for memory blocks having programmed executable tasks. The system includes a memory control block queue for managing all memory control blocks, and an executable task control block queue which is a subset of the memory control block queue and which is regularly updated to include memory control blocks having pointers to only programmed currently-executing tasks and programmed executable tasks. When a search for executable tasks is initialized, only the executable task control block queue need be searched. Unnecessary overhead time needed to search memory control blocks having only unexecutable tasks is eliminated.

Abstract: A television receiver which can display images in different displaying forms on a display screen with an aspect ratio of 16:9 by controlling the video chroma processing circuit by the micro computer by operating the remote controlled signal acceptor or the key switch has memories. The first memory stores video control data for each displaying form and the second memory stores appointed data for designating predetermined video control data. When the displaying form is changed by operating the remote controlled signal acceptor or the key switch, the micro computer reads the video control data corresponding to the displaying form which is newly set from the first memory according to the appointed data of the second memory and changes, for example, the contrast characteristic in the signal processing circuit according to the read data.