Summary: In this paper, we propose a Bi-directional Fragmental Pipelining (BFP) technique and its variable buffer size data-caching scheme BFP\(_{\text V}\) to reduce the disk I/O bandwidth requirement for multimedia servers. Our mathematical analysis shows that the BFP technique is superior to the traditional unidirectional pipelining technique in terms of memory buffer space requirement. We further demonstrate that the memory buffer management using BFP\(_{\text V}\) is better than that of using the fixed buffer size approach BFP\(_{\text F}\). We have mathematically proved that BFP\(_{\text V}\) saves more disk I/O bandwidth than BFP\(_{\text F}\) does using the same memory buffer space. Our simulation results have quantitatively confirmed our analysis.