Binary is another way of counting. Computers only have two fingers.

We count

1-2-3-4-5-6-7-8-9-10-11

computers count

1-2-10-11-

1011

1 eights 0 fours 1 twos 1 ones=11

While studying Biology, learning binary opened her mind.

Why base 2?

Base 10 (decimal) 11

Base 16 (hexadecimal) B

Base 60 (babylonian)

60 has a lot of factors. Good for division.

What has this got to do with computers? What do computers do?

- store data. books do that, too.

- transform data. transforms data into patterns of light on your screen.

- store audio, image, numbers, text. you want one way to store all different kinds of data. Computers use numbers. Numbers can model anything.

core units can store a 1 or a 0. Memory cell.

8 bits in a byte. Bits have 8 digits per number

The Enchantress of Numbers. Ada Lovelace. Babbage called her the Enchantress of Numbers.

Why did we pick binary instead of another system?

Some people did choose decimal for early computers. in the 1800s, Babbage built a mechanical computer. He had two machines. Differential engine (calculator) and the analytical engine. Never completed, but fully designed. He tried to use decimal

The first computer eniac (?) did not use binary. Its programmers were all women. 8 of them.

Memory cells

each has either a one or a zero.

The circuit was invented long ago. High signal or low signal. Very simple.

Enniac represented decimal using binary memory cells

0001000000=3

This is a waste. You can only represent 0-9

If you use binary, you can store 0-255 with the same 10 cells.

Hardware dictated the choice, then, really.

Binary is also used in the Morse code system.

If you want to know the roots of technology, start with the telegraph.

Switches

switches are on or off.

Electromechanical switches send an electrical signal and it does the swithing automatically. It has an electromanet inside. The electromagnet flips the switch.

diagrams for switches for AND, NOT, OR

I never thought of these as switches before.

It's obvious, but never seen it before.

switches can do logic, add, store information.

Eniac contained 17,468 vacuum tubes. Another kind of switch.

Core i7 has 781 million transistors

Computers turn crystals into electromagnetic switches.

Switches are amazing. A neuron is also just a switch.