Introduction to Multiprocessors - Fundamentals of Computer Organization and Architecture - page 240

TABLE 11.2 Example Machines and Their Flynn's
Classification

Classification category Example machines

SISD IBM 704, VAX 11 / 780, CRAY-1

SIMD ILLIAC-IV, MPP, CM-2, STARAN

MISD See observation 5 on page 238

Cm , CRAY XMP, IBM 370 / 168M MIMD

11.2.2. Kuck Classification Scheme

Flynn's taxonomy can be considered a general classification that has been extended
by a number of computer architects. One such extension is the classification intro-
duced by D. J. Kuck in 1978. In his classification, Kuck extended the instruction
stream further to single (scalar and array) and multiple (scalar and array) streams.
The data stream in Kuck's classification is called the execution stream and is also
extended to include single (scalar and array) and multiple (scalar and array) streams.
The combination of these streams results in a total of 16 categories of architectures,
as shown in Table 11.3.
Our main observation is that both Flynn's and Kuck's classifications cover the
entire architecture space. However, while Flynn's classification emphasizes the
description of architectures at the instruction set level, the Kuck's classification
emphasizes the description of architectures at the hardware level.

11.2.3. Hwang and Briggs Classification Scheme

The main new contribution of the classification due to Hwang and Briggs is the
introduction of the concept of classes. This is a further refinement on Flynn's classi-
fication. For example, according to Hwang and Briggs, the SISD category is further
refined into two subcategories: single functional unit SISD (SISD-S) and multiple

TABLE 11.3 The 16-Architecture Categories Resulting from Kuck's Classification

Execution streams

Single Multiple

Instruction
stream

Scalar Array Scalar Array

Single
Scalar Uniprocessor Uniprocessor SIMD

Array ILLIAC-IV

Multiple
Scalar

NYU Ultracomputer Cray X MP

Array