C64 OS has one goal.
Make a Commodore 64 feel fast and useful in today’s modern world.

It's a very high bar. The C64 was introduced in 1982 and has an 8-bit, 1MHz, 6510 CPU with just 64 kilobytes of directly addressable memory. It has a screen resolution of 320x200 pixels, and a fixed palette of 16 colors. But, it is an incredibly versatile machine. And it enjoys an active userbase and a great variety of modern hardware expansions.

The C64 has had many operating systems written for it, So why write another?

Some of these projects were designed to be experimental, or to demonstrate a point, rather than to solve a problem or to make using the C64 better. Others had good intentions but pushed the machine in ways it wasn't designed for, compromising on speed and usability in the pursuit of features available on more powerful computers.1 The aim of C64 OS is to work with the limitations of the Commodore 64 and enable it to become useful.

  1. In alphabetical order: CLiPS, Contiki, GeckOS/A65, GEOS, LUnix/LNG, Wheels, WiNGs. And I'm sure more. []
Written and Maintained by Gregory Nacu


C64OS.com has grown from its original purpose as an outlet for me to blog about my adventures in learning to code in 6502 and my progress towards the development of a simple, single-tasking, event-driven operating system. It is growing into a resource for new and returning users of the Commodore 64 and 128 to find out about all the great new things being developed both in hardware and software.


In the weblog, you'll find posts that cover news, editorial reviews, programming reference documents, technical deep dives into software and hardware, plus thoughts and progress updates on the development of C64 OS.

Over time my posts have gotten longer and more detailed. These in-depth posts take time research, write and edit. I have been keeping to steady pace of at least one such post a month. It is difficult to get regular readers if new content is not showing up more frequently. To help cope with this, the weblog also has an RSS feed. Subscribe to it, and you'll get new posts in your feed reader as soon as they're published. Or follow me on Twitter, where I announce each new post.

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Commodore hardware is great. The architecture has proven to be very well designed as is still usable and expandable decades later. But in order to take advantage of that architecture design, you need to actually expand it by building or purchasing expansion hardware.

Commodore 8-bit computers have had lots of third-party supporting hardware. And while much of it is no longer commercially available, there are hundreds of modern projects and expansion options that are available and under development today. When I returned from my hiatus, I was amazed by the rich support the C64 still has, from hardware, software and publications. However, I learned about these things in dribs and drabs by haunting IRC channels, message boards and following C64 fans on Twitter.

The Commodore 8 Bit Buyer's Guide is a graphical catalog of all the hardware products, projects and kits I know of that are commercially available today. Product feature pages show high-res photos, link to the homepage, documentation and supporting software, include a mini review and product description and list prices and instructions on how you can buy the product for yourself.

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The site is named for this main and overarching project, C64 OS, which I began developing in the fall of 2016. Its goal is to be simple and streamlined and to work with the hardware limitations. I want to make an authentic C64 OS, rather than trying to ape the behavior of other OS platforms. C64 OS exists to provide consistency and usability advantages for the user, and a more modern development platform for the programmer.


  • Event-driven interaction model
  • Advanced mouse and keyboard event system
  • Hybrid memory manager
  • String, Math and File Libraries
  • Text screen compositor
  • Graphical split screen mode
  • Object-oriented widget toolkit
  • System-wide pull down menus
  • Standardized open and save file dialogs
  • Universal cut, copy and paste
  • Application launcher and file manager

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In 2000 I acquired my first SX-64 Executive Computer. A luggable C64 with a built in 5" display, 1541 floppy drive and a unified power supply. All with a handle on the top. I heavily modified mine to include a SuperCPU, IDE64, CD-Rom drive, Ethernet adapter and High Speed RS232, all powered by a lightweight AT Power Supply.

But the SX-64 was built for a different time. Its display is a massive CRT block, 1-foot deep. The rest of the internal layout is modeled around this main feature. C64 Luggable is a project to build an all-in-one C64, oriented vertically rather than horizontally. It has a large 15" LCD display and foregoes old tech like a floppy drive, in favor of SD card and USB-based storage. Ethernet is a standard. And so are its front-mounted 4-player controller inputs, and rear-mounted PS/2 mouse and keyboard ports.

I love my Commodore computers and how expandable they are, but they have a tendency to take up a whole desk with sprawling peripherals and multiple power supplies. This is fun its own way, but it makes them inconvenient to take with you. C64 Luggable is a practical project for me, and a reference design for other people to be creatively inspired. It allows me to bring a C64 with me to my friends' houses, to remove the friction of getting them to be able to enjoy C64 demos and multi-player games with me. C64 Luggable helps me share the love of the C64 more easily and with more people.

Learn more about C64 Luggable ⇒