Abstract: To improve the performance of file accesses for the applications in DSM system, a parallel file subsystem named DPFS has been developed for JIAJIA DSM system. DPFS adopts file mapping interface as its API, which is simpler than read/write interface. With file mapping interface, some features of the DSM system have been utilized to make the implementation of DPFS easier and the performance higher. Experimental results on Dawning 2000 parallel machine demonstrate that DPFS can improve the performance of file accesses and reduce the total execution time of applications.