An Evaluation of Java's I/O Capabilities forHigh-Performance Computing

ABSTRACT Java is quickly becoming the preferred language for writing distributed applications because of its inherent support for programming on distributed platforms. In particular, Java provides compile-time and run-time security, automatic garbage collection, inherent support for multithreading, support for persistent objects and object migration, and portability. Given these significant advantages of Java, there is a growing interest in using Java for high-performance computing applications. To be successful in the high-performance computing domain, however, Java must have the capability to efficiently handle the significant I/O requirements commonly found in high-performance computing applications. While there has been significant research in high-performance I/O using languages such as C, C++, and Fortran, there has been relatively little research into the I/O capabilities of Java. In this paper, we evaluate the I/O capabilities of Java for high-performance computing. We examine several approaches that attempt to provide high-performance I/O-- many of which are not obvious at first glance--and investigate their performance in both parallel and multithreaded environments. We also provide suggestions for expanding the I/O capabilities of Java to better support the needs of high-performance computing applications. 1. INTRODUCTION There is a growing interest in the use of Java for highperformance computing, stemming from Java's significant support for programming on distributed platforms. This support includes compile-time and run-time security that can be used as the basis for writing secure applications. Java also provides inherent support for multithreading, allowing the overlapping of computation with communication or I/O. Java can save the state of an object and recreate that object on another machine, supporting both persistent objects and object migration. Java provides automatic garbage collection, alleviating the programmer from memory management. Perhaps the greatest benefit of Java is its portability: a Java application can be executed on any platform with Java support