说明：  PVM是一个在网络上的虚拟并行机系统的软件包。它允许将网络上基于UNIX操作系统的并行机和单处理机的集合当成一台单一的“并行虚拟机”来使用。PVM支持用户采用消息传递方式编写并行程序。介绍PVM的编程.
(PVM is a network of virtual parallel computer system packages. It allows network-based UNIX operating system and single-processor parallel computer as a collection of single Parallel Virtual Machine to use. PVM support for users to prepare the way message passing parallel programs. Introduction PVM programming.)