# 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 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

• 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.