build-essential           # gcc, make, gcc-c++
bc                        # Calculator (needed for kernel build)
bison                     # Parser generator (kernel needs it)
flex                      # Lexical analyzer (kernel needs it)

Linux Kernel Development

libelf-dev               # ELF library (kernel compression)
libssl-dev               # OpenSSL development (kernel crypto)

Bootloader & ISO Creation

grub-common              # GRUB bootloader utilities
xorriso                  # ISO image creation

QEMU Virtualization

qemu-system-x86          # QEMU x86_64 emulator

Download & Extraction

wget                     # HTTP downloader
xz-utils                 # XZ compression utilities
cpio                     # Archive format tool

Pre-Installation Checklist

Before installing, verify your system:

1. Check Linux Distribution

lsb_release -a

Output should show Ubuntu/Debian variant.

2. Check Free Disk Space

df -h

Look for partition with 30+ GB free. Example:

/dev/sda1       500G  200G  300G  40% /

The / partition has 300G free - sufficient.

3. Check RAM

free -h

Should show 4+ GB available.

4. Check CPU Cores

nproc

Should show 2+ cores. Example output: 8 (8 cores available).

5. Test Network

ping -c 1 8.8.8.8

Should succeed. PanOS needs internet to download sources.

Installation Steps

Method 1: Automatic Installation (Recommended)

Run the dependency installation script:

cd ~/Desktop/Atlas/PanOS
./0-install-deps.sh

This script will:

✅ Check if running on Linux
✅ Detect your distribution
✅ Prompt for sudo password
✅ Update package lists with apt-get update
✅ Install all required packages
✅ Verify installation success

Time Required: 5-10 minutes depending on internet speed.

Method 2: Manual Installation

If automatic installation fails, install manually:

sudo apt-get update

sudo apt-get install -y \
  build-essential \
  bc \
  bison \
  flex \
  libelf-dev \
  libssl-dev \
  wget \
  xz-utils \
  cpio \
  grub-common \
  xorriso \
  qemu-system-x86

Verification Commands

After installation, verify each component:

Verify Build Tools

gcc --version          # GNU C Compiler
make --version         # Make build system

Verify Kernel Build Tools

which bc               # Calculator
which bison            # Parser generator
which flex             # Lexical analyzer
pkg-config --modversion openssl  # OpenSSL version

Verify Bootloader Tools

which grub-mkrescue    # GRUB ISO maker
which xorrisofs        # ISO image creator

Verify QEMU

qemu-system-x86_64 --version  # Should show version
which qemu-system-x86_64      # Should show path

All commands should return without errors.

Troubleshooting Pre-Installation Issues

Error: "Command not found"

Some required tools are missing. Run:

./0-install-deps.sh

Then verify again.

Error: "Permission denied" running `0-install-deps.sh`

Make script executable:

chmod +x 0-install-deps.sh
./0-install-deps.sh

Error: "Not enough space"

You need 30+ GB free. Check with:

df -h /

If not enough space, either:

Delete unnecessary files
Use external hard drive
Create a separate partition

Error: "Unable to locate package"

Package lists are outdated. Run:

sudo apt-get update
./0-install-deps.sh

Error: "E: Could not open lock file"

Another apt-get process is running. Wait and retry:

sleep 30
./0-install-deps.sh

Optional but Recommended

For better development experience, also install:

sudo apt-get install -y \
  git                    # Version control
  vim                    # Text editor
  curl                   # HTTP client (alternative to wget)
  htop                   # System monitor
  screen                 # Terminal multiplexer

Environment Variables

The build scripts use these environment variables:

# Home directory (automatically set)
$HOME

# Workspace for build artifacts
$HOME/pan-os-iso/build/

# Kernel source directory
$HOME/pan-os-iso/kernel-src/

# Rootfs directory
$HOME/pan-os-iso/rootfs/

You can override with:

export WORKSPACE="/custom/path"

System Limits

Some systems have limits that may affect the build:

File Descriptor Limit

ulimit -n          # Check open files limit
# Should be >= 1024

If too low, increase:

ulimit -n 4096     # Temporary
# Or edit /etc/security/limits.conf for permanent

Process Limits

ulimit -u          # Check process limit
# Should be high enough (usually 63000+)

Next Steps

Once prerequisites are verified:

✅ System Ready: Proceed to 03-installation.mdx
📖 Understand the Build: Read 04-building.mdx
🔨 Start Building: Run ./1-build.sh

Previous: 01-getting-started.mdx
Next: 03-installation.mdx

Prerequisites and System Requirements

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