**1.****4**** - ****Building a Computer**

**Let's get our hands dirty!**

Grab a screwdriver and a camera!

**Big ****Review**

Everyone should be complete Unit 0 Lessons

**0.1 to 0.****6**. No new lesson tonight - this is your last chance to get caught up.Always check the course calendar if you're ever wondering "what'd we do"

**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

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**integer***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

The GPU is an upgrade to a CPU in terms of its ability to calculate more complicated mathematics extremely quickly

**News:**

There will be a paper & pencil assessment on everything we have covered so far (see the "Big Review" above)

Any questions? Now's the time...

**Today's Lesson: 1.****4**** - ****Building a Computer**

Today is an in-class demonstration and hands-on activity. There is no slideshow. If you missed today's class you might want to watch some videos on YouTube about parts of a computer and building one.

**Today's Task(s) / Homework**

**TONIGHT:**Are you done lessons 0.1-0.6 ?!?!Study for the quiz (should you feel the need)

**Extra - looking for something to watch and learn from?**