What nobody teaches you anymore.
There was a time when using a computer meant understanding how it worked. Not all of it — nobody knows all of it — but the important parts. How it boots. How programs talk to the kernel. How data gets to the disk. How a packet gets from here to there.
That knowledge is disappearing. Not because it's obsolete — it's more relevant than ever —
but because the industry decided abstractions are better than understanding.
Use Kubernetes. Use Terraform. Use Docker. Don't ask how. Just kubectl apply and move on.
The problem is: when abstractions break — and they always break — you need to understand what's underneath. And if nobody taught you what's underneath, you're stuck. You can't debug what you don't understand.
kldload isn't just an installer. It's a working reference implementation of how a Linux system actually boots, from UEFI firmware to userspace. Every script is readable. Every choice is documented. When you install kldload, you can open the scripts and see exactly how it works. That's the point.
How your computer actually boots
Most people think booting is: press power, wait, see login screen. Here's what actually happens:
1. Firmware (UEFI)
The CPU wakes up and runs the firmware burned into your motherboard. UEFI looks at
a special partition on your disk (the EFI System Partition) and finds a .EFI binary to run.
That binary is your bootloader. The firmware doesn't know or care what operating system you have.
It just runs the binary.
2. Bootloader (ZFSBootMenu)
On a kldload system, the bootloader is ZFSBootMenu. It scans your ZFS pools, finds all the boot environments, and shows you a menu. Pick one, and it loads that environment's kernel and initramfs into memory. This is where boot environments become powerful — you can switch between completely different system states at this point.
3. Initramfs (the mini operating system)
The kernel starts, but it can't mount ZFS yet — ZFS support is a module, and modules live on disk, and the disk is ZFS. Chicken and egg. The solution: the initramfs is a tiny Linux environment packed into RAM that contains just enough to load the ZFS module, import the pool, and mount the real root filesystem. Then it hands off to the real system.
4. systemd (the service manager)
Once the real root is mounted, systemd takes over. It reads unit files that describe every service the system should run, figures out the dependency graph, and starts everything in parallel. Network, SSH, logging, your web server — all managed by systemd. Every service is isolated, restartable, and observable.
5. Your application
Now you're in userspace. Everything above this point exists to get you here. All those layers — firmware, bootloader, initramfs, kernel, systemd — they're infrastructure. They exist so your code can run safely, reliably, and fast. Understanding them means understanding why your application behaves the way it does.
bootloader.sh. The initramfs build is in bootstrap.sh.
The service setup is in profiles.sh. Read them. They're written to be read.