When you played the Nintendo Entertainment System, you were close to the hardware. That’s why you can perform cool stunts like playing tennis to quickly load into the broken worlds of Super Mario Bros. The chips, the memory, the circuit board, everything was designed to serve the little circuit board inside your cartridge (this is to prevent unauthorized games). In the early to mid-1980s, there was no room for anything else.
However, there is enough space for a custom operating system created in 2022, although hardly. According to Inkbox, NESOS 1.0 by Inkbox Software, the 48K operating system, includes “two main applications, a word processor and settings”. The settings app gives you seven cursors, 53 background colors, and the ability to delete eight files that can fit in NVRAM no larger than 2 KB (i.e., on-board memory that does not lose data when the system is powered off). That’s 832 bytes each, or about one full screen of memory. However, you can drag these eight files to any location on your desktop.
NESOS (pronounced “nee-sohs”according to its creator) is fully graphical. Inbox notes that there is already a Family Basic command line system for the NES and its Japanese predecessor Family Computer/Famicom. “I want NESOS to feel like a real operating system that Nintendo could have made for the NES back in the day. How would it look and feel? — says the creator in his video review.
Inkbox is no stranger to NES programming and whimsical code projects, which are beautiful art. They previously created a fruit-based MMO in less than 40 hours (apparently no longer active), Super Mario ROM Hack, which remade the game in the style of the Ming Dynasty short story “Journey to the West “, and a Chinese word processor for the Apple II. originally made on the Apple II.
NES gave Inkbox two 256-slot sprite memory grids to work with, one for the foreground and one for the background, although the system can only display 64 sprites at a time. However, you can combine 8×8 sprites into larger OS and UI shapes. In terms of input, the HVC-007 keyboard was bundled with some versions of the Family Basic. Inkbox imported the characters used in Super Mario Bros., gave the keyboard a few extra keyboard shortcuts, and had a tiny typing app. If you’re using a standard NES controller, you hold A to cycle through characters, pressing B for space and holding Select with any of those keys to change them.
The Inkbox video goes on to explain how it all works in the NES memory, including manipulating the Imaging Processing Unit (PPU), giving its virtual NES cartridge the same type of storage as battery-powered games, and moving each file, byte by byte, between them.
You can download emulator-enabled NESOS ROMs from the Inkbox website or from ROMHacking. Two frames and eight pixels in gratitude to Hackaday for pointing us to this miracle.