Moore’s Law and the Binary System

TransistorIn 1965, an engineer at the Fairchild Semiconductor Company wrote a paper for Electronics magazine in which he predicted that the number of transistors within an integrated circuit would double every two years. As the years progressed, this prediction was found to be startlingly accurate. This engineer was Gordon Moore, and the prediction came to be known as Moore’s Law. To understand the law a little better, it helps to understand what transistors do.

Transistors are like switches. They can be flipped on or off. You’ve probably heard of binary code, which looks like this: 0110 1100. A zero means the switch is off, and a one means the switch is on. Apple’s first highly successful computer, the Apple II, had a total of 3,510 transistors. The CPU in Apple’s late 2012 iMac has about 1,160,000,000 transistors.

I’m going to take a moment to explain how a binary number system works. It’s really quite simple!

Let’s start by counting from 0 to 5:

0000 0000
0000 0001
0000 0010
0000 0011
0000 0100
0000 0101

Do you see the pattern?

Each 0 or 1 represents a bit. A 0 means the bit is off and a 1 means the bit is on. From right to left, the bits represent 1, 2, 4, 8, 16, 32, 64, 128. So when you want to represent the number 2, you only turn on the bit that is second from the right. The number 5 is represented by 0101 because we’re leaving 8 and 2 turned off while turning on 4 and 1.

In the example above, I used 8 bits. If all 8 bits were set to 1, the number would represent 128+64+32+16+8+4+2+1 = 255. See, easy, right? Now that it’s all coming together, I’m going to blow your mind. 8 bits = 1 byte. You’ve seen that word before – byte! Kilobytes, megabytes, gigabytes…terabytes? A kilobyte stores 1000 bytes of information, or 8000 bits.

Come back next week to read about terabytes!