Host OS Requirements

You need supporting software to build things. This exact list may vary depending on the system you have.

Install needed software/libs. On Arch/Omarchy 3.1:

Cross-compiler:

Emulation

86Box is also good but slower. Bochs is the best but for debugging, not needed here.

For emulation I will be using qemu.

Kernel

Get the sources for the latest compatible kernel 6.14.11:

Now, that you have them in linux/ directory lets configure and build our custom kernel. First create tiniest base configuration:

This is a bootstrap with absolute minimum features. Just enough to boot the system. We want a little bit more.

Add additonal config settings on top of it:

Important: Do not uncheck anything in options unless specified so. Some of those options are important. You can uncheck but on your own risk.

From menus choose those options:

• General Setup
  • Configure standard kernel features (expert users)
    • Enable support for printk
  • Initial RAM filesystem and RAM disk (initramfs/initrd)
    • Support initial ramdisk/ramfs compressed using XZ and uncheck everything else
• Processor type and features
  • x86 CPU resources control support
  • Processor family
• Enable the block layer
• Executable file formats
  • Kernel support for ELF binaries
  • Kernel support for scripts starting with #!
• Device Drivers
  • Block devices
    • Normal floppydisk support
    • RAM block device support
      • Default number of RAM disk: 1
  • Character devices
• File systems
  • DOS/FAT/EXFAT/NT Filesystems
  • Pseudo filesystems
    • /proc file system support
    • sysfs file system support
  • Native language support
• Library routines
  • XZ decompression and uncheck everything under it

Exit configuration (yes, save settings to .config).

Time for compiling!

Compile Kernel

This will take a while depending on the speed of your CPU. In the end the kernel will be created in arch/x86/boot/ as bzImage file.

Move kernel to our main directory and go back to it:

Without tools kernel will just boot and you will not be able to do anything. One of the most popular lightweight tools is BusyBox. It replaces the standard GNU utilities with way smaller but still functional alternatives, perfect for embedded needs.

Get the 1.36.1 version from busybox.net or Github mirror. Download the file, extract it, and change directory:

Remember to be in the working directory.

As with kernel you need to create starting configuration:

You may skip this following fix if you are building on Debian/Fedora

Fix for Arch Linux based distributions:

Now the fun part. You need to choose what tools you want. Each menu entry will show how much more KB will be taken if you choose it. So choose it wisely :) For the first time use my selection.

Run the configurator:

Choose the following options. Remember to do not uncheck anything if not stated here.

• Settings
  • Support files
  • Build static binary (no shared libs)
• Coreutils
  • cat
  • cp
  • df
  • echo
  • ls
  • mkdir
  • mv
  • rm
  • sync
  • test
• Console Utilities
• Editors
• Init Utilities
  • init
    • uncheck everything else (inside init: keep [*] only on init in this page)
• Linux System Utilities
  • mdev
  • mount
    • Support lots of -o flags
    • uncheck evrything else
  • umount
• Miscellaneous Utilities
• Shells
  • Choose alias as (ash)
  • ash
  • Optimize for size instead of speed
  • Alias support

Now exit with save config.

Cross Compiler Setup

Our target system needs to be 32-bit. To compile it on 64-bit system we need a cross compiler. You can setup this by hand in the menuconfig or just copy and paste those four lines.

Setup paths:

Compile BusyBox

Build tools and create base filesystem (“install”). It will ask for options, just press enter for default for all of them.

This will create a filesystem with all the files at **_install/**. Move it to our main directory. I like to rename it to.

Lastly to to that new directory.

Filesystem

You got kernel and basic tools but the system still needs some additional directory structure.

This created minimum viable directory structure for satisfying the basic requirements of a Linux system.

Remember to be in the filesystem/ directory.

Next step is to add minimum configuration files. First one is a welcome message that will be shown after booting.

Here is the first real opportunity to go wild and make this your own signature.

Or download my welcome file.

It looks like that:

$ cat welcome

                _________________
               /_/ FLOPPINUX  /_/;
              / ' boot disk  ' //
             / '------------' //
            /   .--------.   //
           /   /         /  //
          .___/_________/__//   1440KiB
          '===\_________\=='   3.5"

_______FLOPPINUX_V_0.3.1 __________________________________
_______AN_EMBEDDED_SINGLE_FLOPPY_LINUX_DISTRIBUTION _______
_______BY_KRZYSZTOF_KRYSTIAN_JANKOWSKI ____________________
_______2025.12 ____________________________________________

Back to serious stuff. Inittab tells the system what to do in critical states like starting, exiting and restarting. It points to the initialization script rc that is the first thing that our OS will run before dropping into the shell.

Create an inittab file:

And the init rc script:

Make the script executable and owner of all files to root:

Compress this directory into one file. Then go back to working directory.

Create booting configuration.

Another place to tweak parameters for your variant. Text after SAY is what will be displayed on the screen as first, usualy a name of the OS.

The tsc=unstable is useful on some (real) computers to get rid of randomly shown warnings about Time Stamp Counter.

Remember to be in the working directory.

Make it executable:

Create sample file

To make the system a little bit more user friendly I like to have a sample file that user will be able to read and edit. You can put anything you want in it. A simple help would be also a good idea to include.

Filesystem is ready. Final step is to put this all on a floppy!

Boot Image

First we need an empty file in exact size of a floppy disk. Then format and make it bootable.

Create empty floppy image:

Format it and create bootloader:

Mount it and copy syslinux, kernel, and filesystem onto it:

Done!

Test in emulator

It’s good to test before wasting time for the real floppy to burn.

Boot the new OS in qemu:

If it worked that means You have successfully created your own distribution! Congratulations!

The floppinux.img image is ready to burn onto a floppy and boot on real hardware!

Floppy Disk

<!> Important <!>

Change XXX to floppy drive name in your system. In my case it is sdb. Choosing wrongly will NUKE YOUR PARTITION and REMOVE all of your files! Think twice. Or use some GUI application for that.

After 5 minutes I got freshly burned floppy.

Summary

• FLOPPINUX: 0.3.1 (December 2025)
• Linux Kernel: 6.14.11
• Busybox: 1.36.1
• Image size: 1440KiB / 1.44MiB
• Kernel size: 881KiB (bzImage)
• Tools: 137KiB (rootfs.cpio.xz)
• Free space left (df -h): 253KiB

System Tools

File & Directory Manipulation

• cat - display file contents
• cp - copy files and directories
• mv - move/rename files and directories
• rm - remove files and directories
• ls - list directory contents
• mkdir - creates directory

System Information & Management

• df -h - display filesystem disk space usage
• sync - force write of buffered data to disk - use this after any changes to the floppy filesystem
• mount - mount filesystems
• umount - unmount filesystems

Text Processing & Output

• echo - display text output
• more - page through text output

Utilities

• clear - clear terminal screen
• test - evaluate conditional expressions

Applications

Download