Introduction to Multiprocessors - Fundamentals of Computer Organization and Architecture - page 243

Instructions

D DP

IP

Operand
Addresses

Operations State Instructions Addresses

Instruction Memory
(IM)

Data Memory (DM)

Figure 11.5 Abstract model of a simple machine

TABLE 11.4 Possible Connection Schemes

Connection type Meaning

1-1 A connection between two single units

1-n A connection between a single unit and n other units

n-n n(1-1) connections

n n n(1-n) connections

connections. Table 11.4 illustrates the different connection schemes identified by the
classification.
Using the given connection schemes, Skillicorn arrived at 28 different classes.
Sample classes are shown in Table 11.5. The rightmost column of the table indicates
the corresponding Flynn's class. Figure 11.6 illustrates four example classes accord-
ing to the classification.
Major advantages of the Skillicorn classification include (1) simplicity, (2) the
proper consideration of the interconnectivity among units, (3) flexibility, and (4)
the ability to represent most current computer systems. However, the classification

TABLE 11.5 Sample Connection Classes

Class IP DP IP-DP IP-IM DP-DM DP-DP Description Flynn

1 1 1 1-1 1-1 1-1 None Von Neumann

uniprocessor

SISD

2 1 N 1-n 1-1 n-n n n Type 1 array

processors

SIMD

n n

3 1 N 1-n 1-1 None Type 2 array

processors

SIMD

4 N N n-n n-n n-n n n Loosely coupled

von Neumann

MIMD

5 N N n-n n-n n n None Tightly coupled

von Neumann

MIMD