Introduction to Multiprocessors - Fundamentals of Computer Organization and Architecture - page 255

of our topic on Advanced Computer Architecture and Parallel Processing
(see reference list) more will be said about interconnection networks and their
performance metrics. Shared-memory and message-passing architectures are
explained in Chapters 4 and 5, respectively, of the same reference mentioned
above.

EXERCISES

1. Consider the five classifications of computer architectures discussed in this
chapter. You are required to provide a list showing the advantages and dis-
advantages of each classification in view of the degree to which each classi-
fication satisfies the purpose for which a classification is needed.
2. You are required to derive, out of the five provided classifications, a new
classification that outperforms each of the five classifications. Provide, in a
tabular form, the additional advantages and eliminated shortcomings of the
proposed classification.
3. Provide a list of the main advantages and disadvantages of SIMD and MIMD
machines.
4. Provide a list of the main advantages and disadvantages of shared-memory
and message-passing paradigms.
5. List three engineering applications, with which you are familiar, for which
SIMD is most efficient to use, and another three for which MIMD is most
efficient to use.
6. Consider the case of connecting N processors and N memory modules using
each of the interconnection networks shown in Figure 11.1. Assume that T
is the time required for a processor to access an item in a memory module
and that all processors make a request to access distinct memory module.
Compute the worst-case possible delay expected in each of the four inter-
connection networks.
7. It was mentioned that a given SIMD machine could be characterized using a
five-tuple (N, C, I, M, F). You are required to select three different recent
SIMD machines and provide in a tabular form each of the five-tuples that
characterizes them.
8. Assume that a simple addition of two elements requires a unit time. You are
required to compute the execution time needed to perform the addition of a
40 40 element array using each of the following arrangements:

(a) An SIMD system having 64 processing elements connected in nearest-
neighbor fashion. Consider that each processor has only its local memory.
(b) An SIMD system having 64 processing elements connected to a shared
memory through an interconnection network. Ignore the communication
time.