Before we start

Sign in

1Open your phone's camera
2Point it at the code
3Tap the link and fill in the form

No phone? Tell a mentor and we'll sign you in.

Today Session 1 · How Computers Think Rookie Bootcamp · Programming Track

📋 Attendance

forms.gle/os9g31bhyXHY3bPd6

Rookie Bootcamp · Programming Track · Session 1

How
Computers
Think

From a switch to a robot

Warm-up

Where are the computers in this room?

📱Your phone

💻Laptops

🧮Calculators

🔑Car key fobs

📺The TV

⌚Smart watches

🤖

The robot's controller

By the end of bootcamp, you'll program this one.

Today's plan

We'll climb from a single switch to a robot

Each section adds one rung. By the end, you'll know what really happens when you press Deploy.

01

What's inside a computer

★ Story time

1945How big was a computer?

From a room
to your pocket

1940s"Computers" were people doing math by hand. NASA's Katherine Johnson checked the math for John Glenn's 1962 orbit.

1945ENIAC, one of the first electronic computers, weighed about 30 tons and filled a room.

1969The Apollo computer flew astronauts to the Moon with about 4 KB of working memory.

TodayYour phone has millions of times more memory than Apollo.

ENIAC · room-sized · 30 tons

Apollo

← your phone
(click ENIAC or Apollo to see the real one)

Same ideas inside. Just smaller, faster and cheaper every year.

The big picture

Every computer does three things

Input

Keyboard, mouse, touchscreen
Robot: joysticks, sensors

Process

The CPU follows instructions and makes decisions

Output

Screen, speakers
Robot: motors, lights

…and it Remembersstorage keeps programs and data for later

Inside the box

Four parts work together like a kitchen

👩‍🍳The chef

CPU

Does the work, one step at a time, billions of steps per second.

🍽️The counter

Memory (RAM)

Holds what you're working on right now. Fast, but small.

🥫The pantry

Storage

Keeps everything, even when the power is off.

🚪The doors

Input / Output

Orders come in, finished dishes go out.

★ And the recipe?That's the program: the step-by-step instructions the chef follows.

Compare

Memory forgets. Storage remembers.

The counter

RAM

Super fast
Smaller (8 to 16 GB in a laptop)
Erased when the power goes off

VS

The pantry

Storage

Slower
Bigger (hundreds of GB)
Keeps everything with the power off

◆ On the robotEvery time you turn the robot on, RAM starts empty and the code loads from storage. That's the "boot up" you'll wait through at every match.

Top view of a Raspberry Pi 5 computer board

1Processor

2RAM

3microSD slot

4Power (USB-C)

5Wi-Fi radio

6GPIO pins

7USB ports

Photo: Simon Waldherr, CC BY 4.0, via Wikimedia Commons

▶ Try it · 3 min

A Raspberry Pi 5: a whole computer on one small board. Name the parts!

1Processor (CPU) · the chef, 4 cores

2RAM · the counter

3Storage (microSD) · the pantry

4Power (USB-C) · 5 volts in

5Wireless · Wi-Fi and Bluetooth

6GPIO pins · wire up sensors, lights

7USB & network · input/output

★ Our new robot brainThe new FRC controller, SystemCore, is built on a Raspberry Pi Compute Module 5: this same processor and RAM on a small plug-in card.

Let students guess each number before you click. Each click reveals one answer on the photo and in the list.
1 · Processor: the shiny Broadcom chip (BCM2712), 4 CPU cores. The chef.
2 · RAM: the black chip just above it. The little "MEMORY 1G/2G/4G/8G" marking next to it shows which size this board has.
3 · Storage: the microSD card slot is on the underside, at this edge; the card holds the operating system and files. The "PCIe" connector right beside it can connect a fast SSD.
4 · Power: USB-C, 5 volts.
5 · Wireless: the silver can is the Wi-Fi and Bluetooth radio.
6 · GPIO (General Purpose Input/Output) pins: wire sensors, buttons and LEDs straight to the computer. Robot controllers have the same idea as their DIO ports.
7 · USB ports (plus the Ethernet jack below them, and two micro-HDMI ports along the bottom for screens). The square black chip in the middle (RP1) is Raspberry Pi's own chip that runs all this input/output.
Bonus: SystemCore, the new FRC robot controller, uses a Raspberry Pi Compute Module 5: the same BCM2712 processor and RAM on a small card that plugs into the controller. So this board is basically a cousin of our robot's brain. Show a SystemCore if you have one.

02

How we count (and how computers count)

★ Story time

10fingers. That's it.

Why do we count in tens?

Ask"Why ten?" Hold up your hands. You run out of fingers at 10, so you start a new column.

IndiaOur digits 0 to 9 come from India, along with a huge idea: place value and zero. The same "2" can mean two, twenty or two hundred.

~1200Arab scholars spread the system, and it reached Europe around 1200 (thanks to Fibonacci).

2

Hundreds

200

4

Tens

40

5

Ones

5

= 245 our team number!

★ Story time

4,000years ago in Mesopotamia

The Babylonians counted in sixties

WhoThe Sumerians, and later the Babylonians (modern-day Iraq), used base 60.

Why 60?It splits evenly a lot of ways. Great for sharing grain and trading.

÷2 = 30÷3 = 20÷4 = 15÷5 = 12÷6 = 10÷10 = 6÷12 = 5

60seconds

60minutes

360°in a circle

When the robot's gyro says "turn 90°," that's Babylonian math running on a computer.

▶ Try it · 1 min

Count to 60 on your hands, Babylonian style

Your thumb taps the 12 finger segments on one hand. Each time you reach 12, raise one finger on the other hand. 12 × 5 = 60. (A popular theory for why they picked 60.)

10

11

12

7

8

9

4

5

6

1

2

3

thumb
taps

Right hand: 12 segments

12

24

36

48

60

Left hand: dozens

0

0 × 12 + 0

Quick world tour Optional

Number systems are a human choice

🦶

The Maya: base 20

Fingers and toes. Twenty was their "ten."

🇫🇷

French: 80 = "four twenties"

In French, 80 is quatre-vingts, a leftover from counting in twenties.

🥚

Dozens: base 12

12 eggs, 12 months, 12 hours on a clock face, 12 inches in a foot.

◆ The questionSo what would you count in if you only had two fingers?

★ Story time

Meet the Zibbits
from planet Duo. One finger per hand.

Zibbit writes	It means
0	zero
1	one (out of fingers!)
10	two (start a new column)
11	three
100	four

10A Zibbit birthday cake that says 10 is for a two-year-old.

★ Quick questionA Zibbit says it's 1111 years old. How old is it? → 15!

Plot twist

Computers
are Zibbits

OFF = 0

ON = 1

A switch has only two states, so computers count in base 2: binary.

"There are 10 kinds of people: those who understand binary and those who don't."

Place values

In binary, each place is worth double the last

Decimal: each place is ×10

1000

×10

100

×10

10

×10

1

Binary: each place is ×2

128

64

32

16

8

4

2

1

Same idea as decimal. Only two digits: 0 and 1.

Watch it count

Four switches can count from 0 to 15

Click any bulb to flip it. Notice the rightmost bulb flips every time, like an odometer.

▶ Try it · 2 min

Count in binary on one hand

Each finger is a bit

Show 5
Show 10
Show 21
Show 31 (all up!)

One hand counts to 31. Two hands reach 1,023.

Binary → decimal

Add up the places that are on

8

4

2

1

0

1

8

0

2

1

8 + 0 + 2 + 1

= 11

So the Zibbit who was 1111 years old? 8 + 4 + 2 + 1 = 15.

Decimal → binary

Our team number in binary

Take the biggest place that fits, subtract, repeat.

Start: 245

245 − 128 = 117

117 − 64 = 53

53 − 32 = 21

21 − 16 = 5

8 doesn't fit → 0

5 − 4 = 1

2 doesn't fit → 0

1 − 1 = 0 ✓

245 = 11110101. Our team number fits exactly in 8 switches.

Binary math

Binary addition has just four rules

0+0 = 0

0+1 = 1

1+1 = 10write 0, carry 1 (like 9 + 1)

1+1+1 = 11write 1, carry 1

1

0

1

0

1

5

+

0

1

3

1

0

8 ✓

Right to left, carry when you hit 10. Same as decimal, just sooner.

▶ Try it · 5 min

Your turn: pen and paper first, then check

Binary → decimal

101 = 5
1111 = 15
10010 = 18
11110101 = 245

Decimal → binary

7 = 111
12 = 1100
20 = 10100
Your age

Add

0011 + 0001 = 0100
0101 + 0011 = 1000
0110 + 0111 = 1101
1111 + 0001 = 10000 ⚠

Check on your laptop: Windows: Calculator → menu → Programmer (BIN / DEC) · Mac: Calculator → View → Programmer (⌘3) · Chromebook: search Google for "1011 binary to decimal"

Bits and bytes

8 bits make a byte

1 bit

One switch: 0 or 1

1 byte = 8 bits

256 combinations: 0 to 255. Enough for one letter or one number up to 255.

KB

thousand bytes · a text message

MB

million bytes · a song or a photo

GB

billion bytes · a movie, a phone's RAM

TB

trillion bytes · a big hard drive

★ Story time

1980An arcade classic

The level that broke the game

In Pac-Man, the level number was stored in one byte. A byte maxes out at 255.

LEVEL

253

2014"Gangnam Style" passed 2,147,483,647 YouTube views, the biggest number the counter could hold. YouTube had to upgrade it.

Computers only have as many bits as we give them.

03

Switches that make decisions

★ Story time

1854
→ 1937An idea waiting 80 years

The logic teacher and the student

GB

1854

George Boole

A mostly self-taught English math teacher invents a math of just TRUE and FALSE. No computers exist. People think it's a curiosity.

CS

1937

Claude Shannon

A 21-year-old student at MIT realizes electrical switches can do Boole's logic. His master's thesis becomes the blueprint for digital computers.

Michigan kid!

Pure MichiganShannon was born in Petoskey, grew up in Gaylord, and graduated from the University of Michigan in 1936. The father of the digital age grew up a few hours north of here.

An idea nobody needed for 80 years now runs every computer on Earth, including our robot.

The switch inside every computer

A switch flipped by electricity: tubes, then transistors

1906

Vacuum tube

Grid: blocking → light OFF

Glass, hot, thumb-sized, burned out often. ENIAC needed about 18,000.

1947

Transistor

Base: no signal → light OFF

No glass, no heat-up, no moving parts. A modern chip has billions.

A tiny signal turns a big current on or off. Wire a few together and you get a logic gate.

Both panels flip on and off by themselves; click a switch to take control.
Vacuum tube (triode, Lee de Forest, 1906): a hot filament boils off electrons. The plate attracts them, so current flows and the light turns on. Put a negative voltage on the grid and it pushes the electrons back: current stops. Small signal on the grid, big current through the tube.
Problems: tubes are glass, big, hot and burn out. ENIAC had about 18,000; engineers were always replacing them (click the photo).
Transistor (Bell Labs, 1947: Bardeen, Brattain, Shockley; Nobel Prize 1956): same job, made of silicon. A small current into the Base lets a big current flow from Collector to Emitter. No heat-up, no moving parts, and they can be made microscopic.
Link: the processor on SystemCore (and the Raspberry Pi) has billions of transistors. Next slide: wire switches into gates.

Logic gates · click the switches

Three basic gates make every decision a computer can make

NOT

Flips it. ON becomes OFF.

AND

ON only if both inputs are ON.

OR

ON if at least one input is ON.

More gates · click the switches

Add a NOT and you get even more gates

NAND

"NOT AND." The opposite of AND: OFF only if both are ON.

NOR

"NOT OR." The opposite of OR: ON only if both are OFF.

XOR

"Exclusive OR." ON if exactly one is ON. Watch for it in two slides.

★ See the little circle?That bubble on the output means NOT: it flips the answer.

◆ SuperpowerNAND and NOR are universal: you can build every other gate out of just one of them. The Apollo computer that flew to the Moon was built almost entirely from NOR gates.

Gates on our robot

The robot makes these decisions 50 times a second

Drive only if the robot is enabled AND the trigger is held

AND

enabled && trigger

Stop the arm if the limit switch OR the e-stop is pressed

OR

limitSwitch || eStop

Run the intake only if it's NOT already full

NOT

!intakeFull

Sneak peek: that right column is real Java. You'll write it next time.

Gates can do math

Two gates can add two bits

0

Sum

0

Carry

XOR ("exclusive or"): ON when exactly one input is ON → the sum bit
AND: ON when both are ON → the carry bit

Turn both on: 1 + 1 = 10. This circuit does exactly what you just did on paper.

Transistors billions of tiny switches

Logic gates NOT, AND, OR, XOR

Adders & memory do math, remember bits

CPU runs your programs

Stacking up

A CPU is a very well-organized pile of switches

Nothing magic. Just switches, built into gates, built into bigger and bigger pieces.

▶ Try it · 4 min

Be a half adder: 4 people add two bits

🙋Ainput

🙋Binput

→

🧑‍🔧ANDthe Carry

🧑‍🔧XORthe Sum

The rules

A, B: hand up = 1, hand down = 0. Mentor tells you which.
XOR: hand up if exactly one of A, B has a hand up.
AND: hand up only if both have a hand up.
Read the answer: AND then XOR, left to right.

Round	A	B	AND carry	XOR sum	Answer
1	0	0	0	0	00 = 0
2	1	0	0	1	01 = 1
3	0	1	0	1	01 = 1
4	1	1	1	0	10 = 2 ✓

Ask 4 students to stand up and line up in a row: A, B, then AND, then XOR. That order matters: reading the gates left to right gives carry then sum, so round 4 reads 10. Walk through the rules on screen with them before round 1; the rules stay up the whole time, so nobody needs to memorize them.
Each round: whisper the inputs to A and B (or call them out). A and B put hands up or down. The class predicts, then the two gates react. Click once to reveal each round's answer.
Round 4 is the payoff: 1 + 1 = 10, exactly what the half adder slide showed. These four people just did what the circuit does.
Challenge round: gates close their eyes; A and B tap the gates' shoulders instead of raising hands. That's what wires do.
Tie-in: chain enough of these (with one more gate to handle carries coming in) and you can add any numbers. That's the math part of a CPU.

04

Everything is numbers

★ Story time

1844The telegraph

Messages made of two symbols

1844Samuel Morse's telegraph sends messages across the country using only short and long beeps.

S = • • •O = ▬ ▬ ▬E = •T = ▬A = • ▬

Agree on a code, and just two symbols can say anything.

Text

Every letter is secretly a number

A

=

65

=

01000001

★ This code has a nameASCII(say "ASK-ee") American Standard Code for Information InterchangeOne shared table gives every English letter, digit and symbol a number from 0 to 127. Every computer uses the same table, so the "A" you send is the "A" I get.

B66

C67

Z90

a97

!33

😀128,512

When you type a message, your phone is really sending numbers. Emoji don't fit in ASCII's 128 spots, so they come from Unicode, a much bigger table that starts with ASCII.

Pictures

Zoom in far enough and a picture is just numbers

A picture is a grid of tiny squares called pixels.

Each pixel is three numbers: how much red, green and blue (0 to 255).

R 255G 216B 0

= AdamBots Gold. Hover over the picture to read any pixel.

Hover over a pixel

Sound and sensors

Sound and sensor readings are numbers too

Sound is measured thousands of times a second. Each dot is one number.

On our robot

Joystick position-0.73 Drive encoder4,096 ticks Gyro heading87.5° Limit switchtrue

A limit switch is a single bit: pressed or not.

Analog vs. digital · drag the sliders

The real world is smooth. Computers count in steps.

Measurements per wave 16 Bits per measurement 3 bits = 8 levels

Analog (smooth)Digital (steps)

Analog

Smooth, any value in between. Like a ramp, a dimmer knob, or the hands on a clock.

Digital

Exact steps, stored as numbers. Like stairs, a light switch, or a digital clock. Copies perfectly, ignores noise.

◆ On the robotAnalog sensors (like a potentiometer on an arm) send a voltage. The controller's ADC (analog-to-digital converter) turns it into a number your code can use.

Analog = continuous: any value, smoothly changing (a ramp). Digital = discrete: exact steps (stairs). Computers can only store digital, so the real world gets measured and rounded.
Demo: drag "measurements" down to 4 and "bits" down to 1. The gold line becomes a crude square wave. Then drag both up: with 80 measurements and 8 bits (256 levels) it hugs the blue line. That's sampling and resolution, the same reason music files and phone photos look and sound smooth.
Why go digital at all? A copy of a number is perfect, and small noise doesn't change a 0 into a 1. A copy of an analog tape gets worse every time.
Robot tie-in: digital inputs read ON/OFF (limit switch, beam break). Analog inputs read a voltage (potentiometer, pressure sensor) and an ADC turns it into a number. On SystemCore, the I/O ports are run by a separate Raspberry Pi RP2350 chip that does this conversion.

▶ Try it · 4 min

Decode the secret message (real ASCII!)

01000111 01001111
01000010 01001111 01010100 01010011

Each group of 8 bits is one character. Convert to decimal with 128-64-32-16-8-4-2-1, then look it up. Each row is one word.

A65

B66

C67

D68

E69

F70

G71

H72

I73

J74

K75

L76

M77

N78

O79

P80

Q81

R82

S83

T84

U85

V86

W87

X88

Y89

Z90

★ ShortcutEvery capital letter starts with 010 (that's 64). The last 5 bits are its place in the alphabet: 010 00111 → 7 → G.

GO BOTS

05

Programs: recipes for computers

★ Story time

1804
1843Holes, looms and a visionary

The loom and the first programmer

1804Joseph Marie Jacquard builds a weaving loom controlled by cards with punched holes. Change the cards, change the pattern. A program made of holes!

→

1843Ada Lovelace writes step-by-step instructions for Charles Babbage's Analytical Engine. It was never built, but she's often called the first computer programmer. She even guessed machines might one day make music.

A program is just instructions, stored so a machine can follow them.

What is a program?

Computers do exactly what you say, not what you mean

You say"Put peanut butter on the bread."

Computer doesPlaces the whole closed jar on top of the bag of bread. ✓ Done!

What it actually needed

1. Open the bread bag. 2. Take out one slice. 3. Unscrew the jar lid. 4. Pick up the knife. 5. Scoop peanut butter…

▶ Try it · 5 min

Write an autonomous routine: grab the ball, score it

Robot (arrow = facing)Game pieceGoalObstacle

Your program0 steps

Click commands to add steps. Made a mistake? Press ↶ Undo, or click × on any step to remove it.

Robot starts bottom-left, facing right.

Option A: pairs plan the routine on paper (2 to 3 min), then one pair reads theirs out while you enter it and press Run. Option B: the whole class calls out one step at a time.
Fixing mistakes as the class calls out steps: ↶ Undo (or Ctrl+Z / ⌘Z) reverses the last change, including a delete or Clear. Click × on any step to remove it. To fix a step in the middle, click the step before it: new commands are inserted there (gold caret) instead of at the end. Click it again to go back to adding at the end. Don't press Backspace: that goes to the previous slide.
The robot does exactly what's written. "Turn left" is the robot's left, so once it's facing down the screen, left means toward screen-right. Expect at least one crash: that's the lesson. Use Step to find exactly which instruction went wrong (debugging!).
One working answer (23 steps): F, L, F, F, F, R, F, F, F, PICK, F, R, F, F, L, F, F, F, L, F, F, F, SCORE. (F = Forward, L = Left, R = Right.)
Wrap-up question: "That was a lot of 'Forward, Forward, Forward.' How could we make it shorter?" Answers like "Forward 3" or "repeat 3 times" are exactly what parameters and loops are in Java. Teams write real autonomous routines like this for every match.
Don't solve it yet: the next three slides teach if/else and loops, then students replay this field as Level 2.

Control structures · making decisions

if / else lets a program make decisions

The same idea in codeif / else

if (pathClear()) {
    forward();
} else {
    turnLeft();
}

Path clear? YES(click the switch)

★ Every dayIf it's raining, grab an umbrella. Else, grab sunglasses.

◆ Remember the gates?Conditions use AND, OR, NOT: if (enabled && triggerHeld)

Control structures · loops

Loops repeat code so you don't have to

forward() ran0times

Counted loop · "3 times"

repeat (3) {    forward();}

Press Run and watch the loop check before every round.

Condition loop · "until blocked"

while (pathClear()) {    forward();}

Press Run and watch the condition get checked before every move.

★ You've seen one alreadyThe robot's 20 ms loop is a loop that runs for the whole match.

⚠ Infinite loopIf the condition never becomes false, the loop never ends and the program freezes.

Run the counted loop: the robot moves exactly 3 squares. Then run the condition loop: it keeps going until the wall, without anyone counting squares.
Watch the highlight: the loop goes back to the top line and checks before every move. In the while loop the badge shows the answer to pathClear(): true means run the body again, false means skip to the end. The square ahead of the robot flashes green or red to show what it is checking. Have the class call out "true" or "false" before each check appears.
Ask: which one would still work if we moved the wall? (The while loop.)
In Java, the counted loop is written as a for loop, and the condition loop as while. Same ideas, slightly different spelling. We'll write both next session.
Infinite loop example: while (true) { }. On a robot this freezes the code and the robot stops responding.

▶ Try it · Level 2 · 6 min

Level 2: the ball moves! Use if and loops to win

RobotBallPossible ball spot (random each run)Goal

repeat times while / if condition

Build your program. The ▌ shows where the next line goes.

Twist: each Run puts the ball in one of the two dashed circles at random. The 23-step program from Level 1 will only work half the time. Students need if (onBall()) to handle both.
How to build: click a block button. Blocks like repeat, while and if open a { and the next commands go inside. Click } to close it, or } else { to switch an if to its else part. The condition dropdown sets what while and if check. Undo removes the last change.
A winning program (14 commands written vs. 23 before):
forward(); turnLeft(); repeat (3) { forward(); } turnRight(); repeat (3) { forward(); if (onBall()) { pickUp(); } } forward(); turnRight(); repeat (2) { forward(); } turnLeft(); while (pathClear()) { forward(); } turnLeft(); while (pathClear()) { forward(); } score();
Another winner with no if: pathClear() treats the ball as an obstacle until you pick it up, so while (pathClear()) { forward(); } forward(); pickUp(); stops right in front of the ball wherever it is (15 commands).
Run it several times to show it scores no matter where the ball lands. Then ask: "What if the field changed? Which parts would still work?" (The while loops.)
If someone builds while (pathClear()) { } with nothing inside, the robot never moves and the loop never ends. The game stops it and calls out the infinite loop.

How a program runs

The CPU repeats three steps, billions of times a second

Program in memory

0LOAD 5

1ADD 3

2STORE total

3JUMP 0

Fetch

→

Decode

→

Execute

Register A

0

Memory: total

?

Clock ticks

0

SystemCore's processor ticks about 2,400,000,000 times a second (2.4 GHz). This demo does about one.

Our robot

The robot runs a loop every 20 milliseconds

Read inputs: joysticks, sensors
Decide: your code runs
Set outputs: motors, lights

50×every second, for the whole match

This is WPILib's standard robot loop. It ran at 20 ms on the roboRIO and still does on SystemCore. Teams can change it.

Loops shown since this slide opened (slowed way down): 0

Types of programs

Not all programs are apps

🖥️

Operating systems

Run the whole computer and let other programs share it.

Windows, macOS, iOS, Android, Linux

🎮

Applications

What you open and use.

Games, browsers, Spotify

🔌

Embedded

Hidden inside devices, doing one job.

Microwaves, cars, motor controllers

☁️

Web & cloud

Run on servers far away.

YouTube, Google Docs

★ Where does our robot code fit?It's an application running on our robot controller, SystemCore, which runs Linux. The motor controllers have their own embedded programs too.

What happens when you press the power button?

From power on to your program, in five steps

Your programsbrowser, game, robot code
Shelldesktop or command line: how you talk to the OS
Kernelcore of the operating system
Boot loaderloads the OS
Firmware: BIOS / UEFItiny program in a chip on the board
HardwareCPU, RAM, storage, ports

1

Power on: firmware wakes upThe BIOS (or newer UEFI) is stored in a chip, so it runs even with nothing loaded. It checks the hardware (a "power-on self test") and finds the storage drive.

2

Boot loader starts the OSA small program on the drive copies the operating system's kernel from storage into RAM and starts it.

3

Kernel takes chargeThe kernel runs the whole time. It shares the CPU between programs, hands out memory, and talks to devices through drivers.

4

Shell: you can talk to itThe desktop (or a command-line terminal) appears. It's how you ask the OS to do things, like "open this program."

5

A program loads and runsThe OS copies the program from storage (pantry) into RAM (counter), and the CPU starts fetch, decode, execute. Each running program is called a process.

★ On our robotSystemCore boots the same way: firmware, boot loader, then the Linux kernel. Then it starts a program called the JVM, which loads and runs your robot code. More on that next session.

Each click lights the next layer on the left and explains it on the right.
Firmware: on older PCs it's called BIOS (Basic Input/Output System); newer PCs use UEFI. A Raspberry Pi (and SystemCore, which is built on one) keeps its boot firmware in a small EEPROM chip instead, but the job is the same: wake up, check, find the OS.
Boot loader: examples are GRUB on Linux PCs or Windows Boot Manager. Its only job is to get the kernel into RAM and hand over control.
Kernel: Windows, macOS and Linux each have one. It decides which program gets the CPU next (switching thousands of times a second, so everything seems to run at once), keeps programs from messing with each other's memory, and runs device drivers.
Shell: the "outer layer" around the kernel (kernel is the nut, shell is the shell). On a laptop that's the desktop; on SystemCore there's no screen, so mentors use a command-line shell over the network.
Process: a program that's been loaded into RAM and is running. Ask: how many are running on your laptop right now? (Open Task Manager or Activity Monitor: usually hundreds.)
Setup for next session: the JVM is just another program the OS loads. Then the JVM loads your bytecode. Two layers of "loading."

06

Speaking the computer's language

★ Story time

1952"Amazing Grace"

Grace Hopper and the nanosecond

1950sProgrammers wrote raw numbers. Navy mathematician Grace Hopper wanted to program in words.

"I had a running compiler and nobody would touch it. They told me computers could only do arithmetic."

1952She built one of the first compilers anyway, and later helped create COBOL, a language that still runs many banks today.

PropShe handed out wires 11.8 inches long: how far light travels in one nanosecond (a billionth of a second). "Don't waste nanoseconds!"

↑ 11.8 inches (roughly actual size on a big screen)

Same idea, three languages

Three ways to say "add 5 and 3"

Machine codeWhat the CPU actually reads

10110000 00000101
00000100 00000011

AssemblyA little more human

MOV AL, 5
ADD AL, 3

JavaWhat you'll write

int total = 5 + 3;

High-level languages

We write code for humans, then translate it

👀

Readable

Teammates can understand and fix your code.

🔁

Portable

The same code works on many kinds of computers.

🛡️

Safer

The language catches many mistakes for you.

FRC teams use:

JavaC++Python

Team 245 uses Java!

The translator

A compiler translates your code into machine code

Your codeint total = 5 + 3;

Compilerchecks it, then translates

Machine code10110000 …

Compiled

Like translating a whole book before anyone reads it. Fast to run. (Java, C++)

Interpreted

Like a live interpreter translating while you speak. Easy to try things. (Python)

★ Story time

1995Sun Microsystems

Java's first name was Oak

Early 90sJames Gosling's team builds a language for TV set-top boxes. He names it Oak, after a tree outside his office.

🌳→☕

1995"Oak" was already taken, so they renamed it after Java coffee. That's why the logo is a coffee cup.

Java's big promise: "Write once, run anywhere."

How our code gets to the robot

From your laptop to a moving robot

WriteJava in VS Code
(WPILib)

→

BuildCompiler turns Java
into bytecode

→

DeploySends it to the robot
over its network

→

RunThe Java Virtual Machine
on the robot runs it

Bytecode (simplified)for total = a + b

iload_1      // get a
iload_2      // get b
iadd         // add them
istore_3     // save total

◆ Why bytecode?Bytecode is a "universal" machine code. Any computer with a Java Virtual Machine (JVM) can run it. That's "write once, run anywhere."

Compare

Two kinds of mistakes

The compiler catches it

Syntax error

Like a spelling or grammar mistake.

motor.set(0.5) error: ';' expected

VS

Nobody catches it

Logic error

The code runs, but does the wrong thing.

motor.set(-0.5); // oops → robot drives backward

★ Story time

1947
1999Two famous bugs

A moth and a lost Mars probe

1947Operators of the Harvard Mark II computer found a real moth stuck in a relay and taped it into their logbook. (Engineers already said "bug," which is why it was funny.)

"First actual case of bug being found."

1999NASA's Mars Climate Orbiter was lost. One team's software used pounds, another expected metric newtons. The code ran perfectly: a logic error no compiler could catch.

On our robot: inches vs. meters, degrees vs. radians. Broke it? Great. Now we debug.

Recap

Three things to remember

01

Computers are billions of switches.

02

Binary and gates turn switches into numbers and decisions.

03

Compilers turn our words into those switches.

Quick check · tap an answer

How much do you remember?

1 · What is 1010 in decimal?

8 + 0 + 2 + 0 = 10

2 · Why are there 60 minutes in an hour?

Base 60 from ancient Mesopotamia

3 · Which gate lights only when both inputs are ON?

AND: both must be ON

4 · What does a compiler do?

Your Java → code the machine can run

Up next · Session 2

Intro to
Java

Next time, you write your first program.

Homework · before next session

Install WPILib on your laptop

It comes with its own VS Code, set up for robot code. Don't download VS Code on its own.

1Download

WPILib 2027 Alpha 7 github.com/wpilibsuite/allwpilib/releases/tag/v2027.0.0-alpha-7 Scroll to Assets and pick your file:

Windows 11…Windows-x64…iso
Mac, Apple chip (M1, M2…)…macOS-Arm64…dmg
Mac, Intel chip…macOS-Intel…dmg

Which Mac? Apple menu → About This Mac → Chip.

★ Big downloadAbout 2.5 GB. Download it at home on Wi-Fi.

⚠ Check your laptopNeeds Windows 11 or macOS 15 or newer. Chromebook or older laptop? Tell a mentor.

Installer screens: WPILib docs (docs.wpilib.org), CC BY 4.0. They show an earlier version; yours will say 2027. Click one to zoom.

2Install: take the defaults

Windows: right-click the .iso → Mount → open WPILibInstaller.exe. Mac: open the .dmg → WPILibInstaller.

WPILib installer: Press Start. — Press **Start**

WPILib installer: Leave Everything selected, then press Install for this User. — Keep **Everything**, then **Install for this User**

WPILib installer: Press Download for this computer only, then Next when the download finishes. — **Download for this computer only**

WPILib installer: Wait for the progress bar, then press Finish. Use the WPILib VS Code 2027 icon to start VS Code. — Wait for the bar, press **Finish**

3Done! Open the WPILib VS Code 2027 icon. That's the one we use next session.

We need this installed for the Java exercises next session. Ask students to install it at home this week and bring their laptop charged.
Link: github.com/wpilibsuite/allwpilib/releases/tag/v2027.0.0-alpha-7 (published September 1, 2026; there is no 2027 beta yet). The main releases page marks 2026.2.1 as "Latest", which is the wrong one, so point them at the 2027 link. If a newer 2027 alpha or beta comes out before the session, update the link and QR code.
Defaults all the way: Start, Everything, Install for this User (no admin password needed), Download for this computer only, Finish.
Windows may say "Windows protected your PC": click More info, then Run anyway. If Mount is missing, extract the .iso with 7-Zip. Mac may warn it was downloaded from the internet: click Open. WPILib's docs also ask Mac users to run xcode-select --install in Terminal first; that is needed for C++, so it is optional for us.
Requirements for this alpha: 64-bit Windows 11, macOS 15 or newer, or Ubuntu 26.04. Chromebooks can't run it; plan a shared laptop for those students.
Screenshots are from WPILib's docs and show an earlier version number; every button is the same.

`→SpacePgDnEnter`	Next step or slide (also: click the right half of the screen, or a clicker)
`←PgUpBackspace`	Back (also: click the left half, or right-click)
`Home` `End`	First slide / last slide
`12`… then `Enter`	Jump to a slide number
`T`	Contents: jump to any slide (or the ☰ button, top-left)
`N`	Show or hide speaker notes
`F`	Fullscreen on / off
`?`	This help
`Esc`	Close notes, contents, help or a photo

Sign in

HowComputersThink

Where are the computers in this room?

We'll climb from a single switch to a robot

What's inside a computer

From a roomto your pocket

Every computer does three things

Input

Process

Output

Four parts work together like a kitchen

CPU

Memory (RAM)

Storage

Input / Output

Memory forgets. Storage remembers.

RAM

Storage

A Raspberry Pi 5: a whole computer on one small board. Name the parts!

How we count (and how computers count)

Why do we count in tens?

The Babylonians counted in sixties

Count to 60 on your hands, Babylonian style

Number systems are a human choice

The Maya: base 20

French: 80 = "four twenties"

Dozens: base 12

Meet the Zibbitsfrom planet Duo. One finger per hand.

Computersare Zibbits

In binary, each place is worth double the last

Four switches can count from 0 to 15

Count in binary on one hand

Each finger is a bit

Add up the places that are on

Our team number in binary

Binary addition has just four rules

Your turn: pen and paper first, then check

Binary → decimal

Decimal → binary

Add

8 bits make a byte

1 bit

1 byte = 8 bits

The level that broke the game

Switches that make decisions

The logic teacher and the student

George Boole

Claude Shannon

A switch flipped by electricity: tubes, then transistors

Vacuum tube

Transistor

Three basic gates make every decision a computer can make

Add a NOT and you get even more gates

The robot makes these decisions 50 times a second

Two gates can add two bits

A CPU is a very well-organized pile of switches

Be a half adder: 4 people add two bits

The rules

Everything is numbers

Messages made of two symbols

Every letter is secretly a number

Zoom in far enough and a picture is just numbers

Sound and sensor readings are numbers too

On our robot

The real world is smooth. Computers count in steps.

Analog

Digital

Decode the secret message (real ASCII!)

Programs: recipes for computers

The loom and the first programmer

Computers do exactly what you say, not what you mean

What it actually needed

Write an autonomous routine: grab the ball, score it

if / else lets a program make decisions

Loops repeat code so you don't have to

Counted loop · "3 times"

Condition loop · "until blocked"

Level 2: the ball moves! Use if and loops to win

The CPU repeats three steps, billions of times a second

Program in memory

How
Computers
Think

From a room
to your pocket

Meet the Zibbits
from planet Duo. One finger per hand.

Computers
are Zibbits

Intro to
Java