# 1.4 - Pricing out a Computer

Some Review

Everyone should be complete Unit 0 Lessons 0.1 to 0.5.

Layers of abstraction:

Computers work on binary because of electricity (on or off)

Each 1 or 0 is a "bit", eight bits is a "byte"

Most CPUs are 64-bit these days with 32-bit being the old standard

This means the largest bit is = 2^64 = 18,446,744,073,709,551,616

That means that as a signed integer value a 64-bit processor has a minimum of -9,223,372,036,854,775,808 and a maximum of 9,223,372,036,854,775,807 (that's 9 quintillion)

Transistors create logic gates (direct the flow of electricity) which allows us to perform logic, math, and decisions

Those logic gates are pieced together to create the CPU.

The CPU is the controller - it contains the clock and control unit, "reads" instructions and makes decisions on where data should go

The CPU contains the ALU (Arithmetic Logic Unit) which computes the mathematics

Today's Lesson: 1.4 - Pricing out a Computer

You might want to watch some videos on YouTube about parts of a computer and building one.

Extra - looking for something to watch and learn from?