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.


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 behaviour 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
  • 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


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 of a lightweight AT Power Supply.

But the SX-64 was built for a different time. Its display is a massive CRT block, 1' 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 based storage. And ethernet will be a standard.

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 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 will allow 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.


In my 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.

I have been fairly consistent about making one post per week. That feels like a maintainable pace for me. But it can be 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 the as soon as they are published.

Subscribe to C64OS.com with your favorite RSS Reader

Recent Posts

January 19, 2018Programming Reference

Vic-20 / Commodore 64 SuperChart

December 20, 2017Editorial

World of Commodore '17

December 5, 2017Software

The Big 5 Oh


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 expandable design architecture, 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 available, there are many 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 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 commercially available today. Product feature pages show hi 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.

Author History

Smiling face of Gregory Nacu, the author and maintainer of C64os.com

Gregory Nacu
Author and maintainer of C64OS.com
See nacu.ca for a full bio

I've been a Commodore 8-bit user since I discovered my first computer, a broken Vic-20, under the bed in my parents' guest room when I was 5 years old. They had it repaired for $40 and my journey into computing began.

When I was 9 years old, I got my first Commodore 64 for Christmas in 1990. It changed my life. During the mid 90s I discovered Creative Micro Designs and started buying as much hardware as I could afford. I ended up with numerous C64's C64c's, c128's, a couple of Vic-20's, a c128D and an SX-64. I also got a SuperCPU64 and SuperCPU128 both maxed out with 16megs of SuperRam. I got a Turbo232 and a 33.6Kbps modem and started surfing the web via a dialup shell account. My collection of great hardware kept growing to include a smartmouse, a RamLink, a CMD HD and a SID Symphony. I also acquired numerous Commodore disk drives, 1541's, 1541 II's, 1571's and a 1581.

I started to attend Commodore Expos in the United States in 1998 when I was 17 years old. I showed up with a C64 breadbin slung over my back on a guitar strap. I was in heaven. There were so many cool people and so much great activity going on. I started to dabble more seriously into programming in the late 90s. Shortly thereafter I got hold of an IDE64, and discovered that Jolz Maginnis from Australia was working on a preemptively multi–tasking Unix–like OS for the SuperCPU64, WiNGs (née JOS). I worked with him over IRC to help him debug the TCP/IP stack and my life changed again.

With his tremendous help I taught myself to program in C, and began cross compiling WiNGs software on an iMac and FTPing it to my 64. I cut my teeth writing a bunch of software I had only ever dreamed of having on my C64 when I was kid. And I began to give presentations at Commodore Expos showing off such creations as a Movie player and SpiffyPaint, a multi–layer drawing program. It was a fun and glorious time of my life that I'll never forget.

Present Day

Eventually CMD shut its doors, and the SuperCPU sadly became unavailable. We all grew up, got jobs and moved on with our lives. I packed up my equipment when I moved houses and I didn't have the time to pull it back out. I got married, moved again, and now I've got two children.

When I came back to the scene after 8 years away, I found a bustling community, full of life and energy, with many new projects to fill in the gaps where CMD had left off. A high speed RS232 adapter and a 56K modem are no longer relevant to today's world. But now we have multiple ethernet adapters, commercially available. The CMD HD, and RamLink seem woefully ancient, with bulky SCSI spinning harddisks, or 30 pin RAM simms. Instead SD card adapters are now commercially available in sizes that make them much more useable. Plus they make exchanging data with a PC/Mac easier and faster than it ever was in the heyday.

The SuperCPU is not available. But there are lots of C64s and they need our love. So I have forced myself to get used to the feeling and the pace of 1Mhz again. It was hard to go back from 20Mhz, and even harder to go back from 2.5Ghz. But you do get used to it. What the C64 lacks right now, is a platform upon which to write network–based applications. That's what I want to write, but there is very little out there to help me do that. So, instead, I'm writing a simple single–tasking OS, that will provide the essentials to make it easier to write the apps I've got a creative itch to work on; network–oriented with a consistent mouse–based UI.

This site is about my work on C64 OS, but it's also about helping new and returning users get informed about what is out there, so that you too can live and love your Commodore 64.

I've spent and will continue to spend hundreds of hours working on C64 OS, the Buyer's Guide and the other content of this site. If you want to support my work and help make these projects a reality, please consider sending me a donation via PayPal. Thank you for your support!