3059	 Models for Parallel Processing WIthin Programs Application to CPU I O and I O I O Overlap	 Approximate queueing models for internal parallel processing by individual programs in a multiprogrammed system are developed in this paper. The solution technique is developed by network decomposition. The models are formulated in terms of CPU I O and I O I O overlap and applied to the analysis of these problems. The percentage performance improvement from CPU I O overlap is found to be greatest for systems which are in approximate CPU I O utilization balance and for low degrees of multiprogramming. The percentage improvement from I O I O overlap is found to be greatest for systemtems in which the I O system is more utilized than the CPU. Multiprogramming parallel processing queueing network models multiprocessing of computation and I O
