INPUT/OUTPUT SYSTEM FOR EXTERNAL MEMORY

PURPOSE:To secure a large capacity of an input/output buffer regardless of the length of an object program by setting the input/output buffer and the object program into different logical spaces of a main memory. CONSTITUTION:An object program 4 and an input/output buffer 5 are stored in different logical spaces of a main memory 3. The capacity of the buffer 5 is variable among levels 5a-5c in accordance with the idle capacities decided by the scales 6a-6c of a program 6. Thus the input/output is possible for a large quantity of data that fills a logical space in terms of the capacity of the buffer 5. At the same time, the length accordance with the idle capacity of the memory 3 is secured for the program 4. Then both programs 4 and 6 can be carried out at one time.