Memory is a very important resource to bridge the gap between CPUs and I/O devices. So the idea is to maximize the usage of memory to solve the problem of I/O bottleneck. We developed a multi-threaded task execution engine, which runs in a single JVM on a node. In the execution engine, we have implemented the algorithm of memory scheduling to realize global memory management, based on which we further developed the techniques such as sequential disk accessing, multi-cache and solved the problem of full garbage collection in the JVM. The benchmark results shows that it can get impressive improvement in typical cases. When the a system is relatively short of memory (eg, HPC, small- and medium-size enterprises), the improvement will be even more impressive.