Nekori Arctic¹ is a free and open source operating system developed by Nekori first released on 26 May 2025. The source code is freely available on GitHub (github.com/nekori64/arctic).

As of now, Arctic is only compatible on QEMU and VMware. This is due to how other virtualizors (and emulators) require image files to have a file system, whereas Arctic’s boot disks are binary code.

The latest stable release is version 0.1.5.

Overview

Nekori Arctic is a 16-bit real mode OS, making it compatible with processors going as far back as the 1980 or even earlier.

The OS has a built-in command line interface, which supports basic commands like clear or echo. Due to the OS’ earlierness, disk support is absent from the OS.

Arctic is available in both Standard and Server SKUs, but the Server SKU is exclusive to the Lab02 virtual development lab, also known as Arctic32.

Development

Arctic’s development began around 22 May 2025 (or even earlier) featuring a simple boot screen written in Assembly that eventually evolved into the OS’s command line interface.

Interestingly enough, several instances of a LeafyOS (Arctic’s former name) virtual machine have been seen in Nekori’s VMware VM library. Additionally, screenshots of several kernel.bin files and directory structures going as far back as December 2024 have been sent by Nekori on several Discord servers. All of these files are lost media due to improper backups.

A developer 32-bit version, codenamed Arctic32, was developed alongside Arctic16, while Arctic32 hasn’t been publicly shared, boot attempts date back as far as 28 May 2025²

Kernel Overview

The Arctic loading process involves three key files:

1. bootloader.bin - The Arctic Bootloader, internally codenamed Midori, which is responsible for loading osload.bin.
2. osload.bin - An intermediary component between the bootloader and the kernel, responsible for loading necessary functions and preparing for the launch of rekanto.bin.
3. rekanto.bin - The main Arctic kernel, codenamed ReKanto, which contains all of the operating system’s commands and drivers.

Arctic’s kernel, codenamed ReKanto (a nod to the Kanto region from Pokemon Red & Blue) is a 16-bit monolithic kernel, due to its simplicity. The kernel had to be re-written due to various issues during the transition from 16-bit real mode to 32-bit protected mode. Interestingly enough, another attempt is being made with Arctic32.

The Mockup Era™ Gallery

This gallery showcases the finished Arctic mockups created by Nekori.

Before development began, Nekori designed several Arctic mockups using GIMP. These images are conceptual representations and are not actual screenshots of functional builds—yet!

References