Generation Zero: Mechanical Calculating Machines (1642–1945)

Prior to the 1500s, a typical European businessperson used an abacus for calculations

and recorded the result of his ciphering in Roman numerals. After the

decimal numbering system finally replaced Roman numerals, a number of people

invented devices to make decimal calculations even faster and more accu

rate. Wilhelm Schickard (1592–1635) has been credited with the invention of the

first mechanical calculator, the Calculating Clock (exact date unknown). This

device was able to add and subtract numbers containing as many as six digits. In

1642, Blaise Pascal (1623–1662) developed a mechanical calculator called the

Pascaline to help his father with his tax work. The Pascaline could do addition

with carry and subtraction. It was probably the first mechanical adding device

actually used for a practical purpose. In fact, the Pascaline was so well conceived

that its basic design was still being used at the beginning of the twentieth

century, as evidenced by the Lightning Portable Adder in 1908, and the Addometer

in 1920. Gottfried Wilhelm von Leibniz (1646–1716), a noted mathematician,

invented a calculator known as the Stepped Reckoner that could add,

subtract, multiply, and divide. None of these devices could be programmed or

had memory. They required manual intervention throughout each step of their

calculations.

Although machines like the Pascaline were used into the twentieth century,

new calculator designs began to emerge in the nineteenth century. One of the

most ambitious of these new designs was the Difference Engine by Charles Babbage

(1791–1871). Some people refer to Babbage as “the father of computing.”

By all accounts, he was an eccentric genius who brought us, among other things,

the skeleton key and the “cow catcher,” a device intended to push cows and other

movable obstructions out of the way of locomotives.

Babbage built his Difference Engine in 1822. The Difference Engine got its

name because it used a calculating technique called the method of differences. The

machine was designed to mechanize the solution of polynomial functions and was

actually a calculator, not a computer. Babbage also designed a general-purpose

machine in 1833 called the Analytical Engine. Although Babbage died before he

could build it, the Analytical Engine was designed to be more versatile than his

earlier Difference Engine. The Analytical Engine would have been capable of performing

any mathematical operation. The Analytical Engine included many of the

components associated with modern computers: an arithmetic processing unit to

perform calculations (Babbage referred to this as the mill), a memory (the store),

and input and output devices. Babbage also included a conditional branching

operation where the next instruction to be performed was determined by the result

of the previous operation. Ada, Countess of Lovelace and daughter of poet Lord

Byron, suggested that Babbage write a plan for how the machine would calculate

numbers. This is regarded as the first computer program, and Ada is considered to

be the first computer programmer. It is also rumored that she suggested the use of

the binary number system rather than the decimal number system to store data.