Charles Babbage - Hardware & Software

In designing his Analytical Engine, Babbage was making several key distinctions that are at the heart of computing.

  1. First, Babbage was essentially distinguishing "computing" from mere "calculation."
    Consider, for example, computing your income taxes. Although you probably use a calculator in computing your taxes, a mere calculator cannot do your taxes for you. The process certainly involves many calculations, most of which actually consist of pretty basic arithmetic: addition, subtraction, multiplication, and division. But computing taxes correctly is a matter of doing the right calculations in the right sequence using the right numbers. It means following the steps of the tax form. Or, in computer terms, we could say that in completing the tax form you follow the steps of a program. Although the process of computing one's taxes can seem at first like a long, complicated task, arithmetically it actually consists of a lengthy sequence of fairly simple calculations—again, the key is performing the right calculations in the right order using the right numbers.
  2. Similarly, Babbage realized that, like the tax form, an enormous range of mathematical tasks could be broken down into a sequence of fairly simple calculations.
    As envisioned, the Analytical Engine would be capable of any mathematical task the user desired, as long as that task could be described in terms of a sequence (what we now call a program) of the basic calculations that were performable by the machine.

Babbage was distinguishing between what we now call hardware and software:

  • In terms of its physical structure—its hardware—his machine was capable of a limited range of basic operations.
  • In terms of the sequences of basic calculations—the software—that could be designed for this machine, the possibilities for computing were unlimited. This programmability is at the heart of the difference between a computer and a calculator.
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These pages were written by Steven H. VanderLeest and Jeffrey Nyhoff and edited by Nancy Zylstra
©2005 Calvin College, All Rights Reserved

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