1.4 - Pricing out a Computer

Some Review

• Everyone should be complete Unit 0 Lessons 0.1 to 0.5. 

Layers of abstraction:

1. 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)

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

3. 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