001
LVL 00 — CADET PILOT SESSION 001 DAY 1

WHAT IS THIS MACHINE?

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SYS.SCENARIO
🏢 Welcome to PixelCraft Inc.! HR hands you a laptop and a printed onboarding checklist. The IT admin says: "Before you touch any code, you need to understand what you're working with. Open this machine up — not physically — and tell me what's inside. What are its specs? What can it do? What are its limits?"
CONCEPTS.UNLOCKED
🖥
The Computer
What a computer actually is: CPU (processor), RAM (working memory), Storage (permanent memory), I/O (keyboard, screen, network, USB). Four components — that's it.
⚡
Instruction Cycle
How the CPU executes instructions: fetch → decode → execute → store. Billions of times per second. Every app, every filter, every click — this cycle.
01
Binary
The language of computers — everything is 0s and 1s. Numbers, text, images, colors. There is no "red" inside the machine — only 11111111 00000000 00000000.
📐
Units of Data
Bits, bytes, KB, MB, GB, TB — what they mean physically. 1 byte = 8 bits = one character or one color channel value (0–255).
📁
Files & File Systems
How data is organized on storage — directories, paths, file extensions. Everything has an address. Nothing exists without a location.
⚙
Operating System
What an OS does: manages hardware, runs programs, provides user interfaces (GUI and CLI). It's the layer between you and the silicon.
HANDS-ON.TASKS
01
Inspect Your Machine
▶

Open System Information (Windows), About This Mac (macOS), or run these commands on Linux:

lscpu && free -h && df -h

Write down these specs in a plain text file:

SpecWhere to FindExample
CPU modelSystem Info / lscpuIntel i7-12700H
Number of coresSystem Info / lscpu14 cores
RAM amountAbout / free -h16 GB
Storage capacityThis PC / df -h512 GB SSD
OS versionAbout / uname -aUbuntu 24.04
02
Calculate Image Memory
▶

A pixel = 4 bytes (Red, Green, Blue, Alpha — each 0–255).

Image SizePixelsUncompressed
1080p (1920×1080)2,073,600~8 MB
4K (3840×2160)8,294,400~33 MB

How many 4K images fit in your RAM?

16 GB RAM ÷ 33 MB per image ≈ 490 uncompressed 4K images
Every filter PixelCraft applies operates on these bytes. More pixels = more work = more time.
03
Binary Exercise
▶

Convert these values to binary by hand:

Number 42 → 00101010 Letter "A" (ASCII 65) → 01000001 Color red #FF0000 → 11111111 00000000 00000000
Every filter PixelCraft applies is math on these binary numbers. Images are not pictures inside the computer — they are arrays of numbers.
04
Explore Your File System
▶

Using only your OS file explorer, navigate to:

/Users/yourname/ # macOS / Linux home C:\Users\yourname\ # Windows home

Find your home directory, your desktop, your downloads folder. Understand the path — the address of every file on your machine. Every file has exactly one. No exceptions.

05
Meet PixelCraft as a User
▶

Open PixelCraft in the browser (provided link). Upload a photo. Try every button.

Note what works, what's broken, what confuses you.

Write these observations in a plain text file:

day1-observations.txt
This file is your first engineering artifact. You're not coding yet — you're observing. Engineers observe before they act.
CS.DEEP-DIVE

Binary representation.

The number 255 in binary is 11111111 — that's 8 bits, or 1 byte. This is the maximum value for one color channel.

That's why colors in CSS go from 0 to 255: it's the range of one byte.

// When PixelCraft's brightness filter adds 20...

pixel.R = pixel.R + 20   // +00010100 in binary
pixel.G = pixel.G + 20   // to each channel
pixel.B = pixel.B + 20   // for every pixel

// 1080p = 2,073,600 pixels × 3 channels
// = 6,220,800 additions per filter
// Your CPU does this in milliseconds.

Every image filter is math. Every pixel is a number. Everything the computer does is arithmetic on binary.

"Pixel Math Sheet"
[A] Calculate memory for 10 different image sizes — from thumbnail (100×100) through 8K (7680×4320). Build a table.
[B] Estimate processing time at 1 billion operations/second. How long does a brightness filter take on each image size?
[C] Calculate how long a brute-force password cracker would take for different password lengths. Passwords are 2^n combinations — feel the exponential growth.
REF.MATERIAL
VIDEO
How Do Computers Really Work? — Sebastian Lague
Sebastian Lague
Brilliant visual explanation of how computers work from transistors up to logic gates and beyond.
CPUBINARYLOGIC GATES
VIDEO
How Computers Work — Binary & Data
Code.org · Bill Gates
Short, clear breakdown of binary representation — how computers store numbers, text, images, and sound using 0s and 1s.
BINARYDATA
BOOK
Code: The Hidden Language of Computer Hardware and Software
Charles Petzold
The definitive book on how computers work from first principles — Morse code to microprocessors. Read chapters 1–9 for this session.
HARDWAREBINARYFUNDAMENTALS
VIDEO
How a CPU Works
In One Lesson
20-minute walkthrough of the fetch-decode-execute cycle with clear visual diagrams.
CPUINSTRUCTION CYCLE
ARTICLE
Bits and Bytes — Stanford CS101
Stanford University
Concise reference on bits, bytes, and how data units scale from KB to TB. Good for quick review.
BITSBYTESUNITS
VIDEO
File System Forensics — Computerphile
Computerphile
How file systems organize data on disk — inodes, directories, and paths explained clearly.
FILE SYSTEMSSTORAGE
COURSE
Nand2Tetris — Build a Computer from First Principles
Noam Nisan & Shimon Schocken
The legendary course that builds an entire computer from NAND gates. Optional deep-dive for the curious — revisit after Session 10.
HARDWAREADVANCEDOPTIONAL
// LEAVE EXCITED BECAUSE
Your laptop holds 490 uncompressed 4K photos in RAM. It executes billions of operations per second. PixelCraft's entire job is math on numbers — and you now understand what those numbers are. The machine on your desk is absurdly powerful.