Читать книгу Beginning Programming All-in-One For Dummies - Wallace Wang - Страница 16

Although computer programming may seem like a recent invention, the idea behind writing instructions for a machine to follow has been around for over a century. One of the earliest designs for a programmable machine (in other words, a computer) came from a man named Charles Babbage way back in 1834.

That was the year Charles Babbage proposed building a mechanical, steam-driven machine dubbed the Analytical Engine. Unlike the simple calculating machines of that time that could perform only a single function, Charles Babbage’s Analytical Engine could perform a variety of tasks, depending on the instructions fed into the machine through a series of punched cards. By changing the number and type of instructions (punch cards) fed into the machine, anyone could reprogram the Analytical Engine to make it solve different problems.

The idea of a programmable machine caught the attention of Ada Lovelace, a mathematician and daughter of the poet Lord Byron. Sensing the potential of a programmable machine, Ada wrote a program to make the Analytical Engine calculate and print a sequence of numbers known as the Bernoulli numbers.

Because of her work with the Analytical Engine, Ada Lovelace is considered to be the world’s first computer programmer. In her honor, the Department of Defense named the Ada programming language after Ada Lovelace. Nvidia named a family of graphics cards after Ada Lovelace as well.

Although Charles Babbage never finished building his Analytical Engine, his steam-driven mechanical machine bears a striking similarity to today’s computers. To make the Analytical Engine solve a different problem, you just had to feed it different instructions. To make a modern computer solve a different problem, you just have to run a different program.

Over a century later, the first true computer appeared in 1943 when the U.S. Army funded a computer to calculate artillery trajectories. This computer, dubbed ENIAC (short for Electronic Numerical Integrator and Computer), consisted of vacuum tubes, switches, and cables. To give ENIAC instructions, you had to physically flip its different switches and rearrange its cables.

The first ENIAC programmers were all women.

Physically rearranging cables and switches to reprogram a computer worked, but it was tedious and clumsy. Instead of having to physically rearrange the computer’s wiring, computer scientists decided it would be easier if they could leave the computer physically the same but just rearrange the type of instructions given to it. By giving the computer different instructions, they could make the computer behave in different ways.

In the old days, computers filled entire rooms and cost millions of dollars. Today, computers have shrunk so far in size that they’re essentially nothing more than a little silicon wafer, about the size of a coin.

A processor is essentially an entire computer. To tell the processor what to do, you have to give it instructions written in machine language (a language that the processor can understand).

To make faster computers, engineers combine multiple processors (called cores) together and make them work as a team. So, instead of having a single processor in your computer, the latest computers have multiple processors or cores working together.