sisd

In an SISD architecture there is a single instruction cycle ; operands are fetched serially into a single processing unit before execution .

在单指令流单数据流结构中，有单一的指令周期，在执行前，单个处理机按序取操作数。

Because of this similarity , some methods from high-speed pipeline SISD computers can be extended to array processors or vector computers , and vice-versa .

这一方法使得高速流水线的单指令流-单数据流计算机与阵列机、向量机的一些成果，通过相似性可以相互推广。

Five code types ( SISD , SIMD , MIMD , VECTOR , and MASTER ) which should be specified explicitly by user in parallel programming were defined . The rules for describing the input and output parameters of each code segments were also discussed .

定义了5种用户在并行编程时需显式说明的代码段的类型（SISD，SIMD，MIMD，VEC-TOR，MASTER），以及用户对代码段的输入和输出参数需进行的说明。

Such work is very difficult and some concept and terminology are ambiguous . From the point of view of program structure , the paper clearly presents the formal definitions about SISD , SIMD and MIMD , which are the foundations of extracting program heterogeneity .

这方面的工作难度大，概念和术语含糊不清，本文从程序结构观点出发，清楚地给出了SISD、SIMD、MIMD的形式定义，它是提取程序异构性的基础。