A Detailed Model of the Computer

In this section we develop a detailed model of the running time performance of Java programs. The model developed is independent of the underlying hardware and system software. Rather than analyze the performance of a particular, arbitrarily chosen physical machine, we model the execution of a Java program on the ``Java Virtual Machine'' (see Figure ).

A direct consequence of this approach is that we lose some fidelity--the resulting model cannot predict accurately the performance of all possible hardware/software systems. On the other hand, the resulting model is still rather complex and rich in detail.

  
Figure: Java system overview.

• The Basic Axioms
• A Simple Example-Arithmetic Series Summation
• Array Subscripting Operations
• Another Example-Horner's Rule
• Analyzing Recursive Methods
• Yet Another Example-Finding the Largest Element of an Array
• Average Running Times
• About Harmonic Numbers
• Best-Case and Worst-Case Running Times
• The Last Axiom

Copyright © 1998 by Bruno R. Preiss, P.Eng. All rights reserved.