CoCo 3’s NitrOS9 “Ease of Use” edition on your PC/Mac

Updates:

  • 2002-7-9 – Corrected information on the company that originally released NitrOS9 (thanks to L. Curtis Boyle, one of the developers).

TL:DNR

Put six files in a directory:

  • 68IDE.ide
  • bas11.rom
  • coco3.rom
  • hdblba.rom
  • xroar.conf (which you will make, below)
  • xroar.exe (or xroar.app for Mac)

Where “xroar.conf” contains the following text:

machine coco3
tv-input rgb
machine-cart ide
cart-rom hdblba.rom
load-hd0 68IDE.ide
kbd-translate
default-machine coco3

Then run xroar.exe (or xroar.app for Mac) to load up a virtual CoCo 3, then . From there, type “DOS” to boot into NitrOS9 Ease of Use.

You can also just download a zip for Windows here or this zip for Mac OS X. (But seriously, you should really never just run some random zip file someone posts to a blog. Links to where to get these files separately are in the article below.)

OS-9: The story so far…

In 1980, Microware Systems Corporation released the OS-9 operating system for the still-new Motorola 6809 processor. In the years that followed, OS-9 grew and evolved, initially by being enhanced for the Motorola 68000 family of processors, then later Intel x86, PowerPC, StrongARM, Sparc, MIPS, Hitatchi SH-3/4 and probably some others that time has forgotten about.

In its day, OS-9 was a stunning achievement. It was a Unix-like environment with multi-user support, multitasking, and a unified I/O system. OS-9 computers allowed many simultaneous users to be logged in via serial terminals at the same time, each running applications or developing code.

OS-9 could also be ran completely from ROM with no file system required. This allowed it to be used in deeply embedded devices. OS-9 boxes flew on the Space Shuttle. OS-9 was part of the 2070 traffic controller specification for intersection traffic lights.  You may have even “heard” OS-9 without knowing it, as it was part of early 1980s music synthesizers from Fairliight, and was in audio playback devices used by radio stations and even Walt Disney World.

But I digress…

OS-9 at Radio Shack?

When Radio Shack introduced the TRS-80 Color Computer in 1980, it was the first mass-produced 6809 computer system. Though initially starting as a 4K or 16K computer using a cassette recorder for program storage, within a few years disk drives and memory expansion to 64K was available. This allowed a port of OS-9 to be made available for the CoCo. It was sold at Radio Shack stores nationwide.

Yes, Virginia. In the 1980s you could buy a multi-user, multitasking Unix-like operating system for a home computer at more stores than even McDonald’s had at the time.

With the 1986 introduction of the Color Computer 3 came new hardware capabilities. 128K was standard, and officially expandable to 512K. Screen resolution was increased to 640×225, with an 80 column text screen. There was a new memory management unit (MMU) that allowed banking in 8K blocks of memory in to the 64K address space that the 6809 could access.

And thus, OS-9 Level 2 (the version that supported MMUs) became available at Radio Shack. Developers like Lucasfilm Games and Sierra Online wrote their CoCo 3 games under OS-9.

Yes, Virginia, you could play games like King’s Quest III, Leisure Suit Larry and Rescue on Fractalus while multitasking to get your homework done in the background…

6309: Attack of the clone

Within a few years of the 6809 being introduced, Hitachi released a lower power clone called the 6309. While this was never used by Radio Shack in the Color Computers, hobbyists used them as replacement CPUs.

Most didn’t know this at the time, but the 6309 had secrets. It had undocumented capabilities, including a “native mode” that ran faster than a stock 6809.

Color Computer software companies such as Burke & Burke and Gale Force Enterprises began selling patches to modify OS-9 to use these 6309 features. These patches created new demand for the 6309 as OS-9 users began replacing their CPUs to get faster performance. There were even patches sold to speed up the Microsoft Color BASIC ROMs.

And then the world moved on to Windows PCs…

Retro resurgence

Today, the NitrOS9 project is alive and well, and the code has been back-ported to run on a stock 6809 CoCo, and versions now exist for even the 64K Color Computer 1 and 2 models:

http://www.nitros9.org/battle.html

From that site, you can download .DSK images that can be written out to a real floppy disk (if you have such hardware) and used on a real Color Computer. You can also use it on various emulators, allowing you to run CoCo OS-9 from a modern Windows, Mac or Linux machine. (There’s even a Raspberry Pi project, CoCo-Pi, that has an image full of CoCo emulators and software.)

OS-9 is not for the casual point-and-click user. It is a complicated command line environment that came with hundreds of pages of technical documentation. Booting one of those disk images merely leads to a cryptic command line prompt, similar to how early PCs booted up to MS-DOS.

XRoar emulator as a CoCo 3 booting NitrOS9.

However, the NitrOS9 Ease of Use project, lead by one of the original NitrOS9 developers, provides ready-to-run hard drive images of NitrOS9 preloaded with point-and-click windowing environments and many applications, games and utilities:

http://www.lcurtisboyle.com/nitros9/nitros9.html

Versions are made available for the stock 6809 CPU and the enhanced Hitatchi 6309 CPU. There are builds for running on a real Color Computer, or certain emulators (MAME and VCC, currently).

VCC is Windows-only, and MAME has its own learning curves, so I chose to go with the XRoar emulator. It is super easy to set up, and can be ran on Windows, Mac OS X or Linux (including the Raspberry Pi).

Unfortunately, the NitrOS9 Ease of Use edition does not come with a configuration that works on XRoar. While XRoar emulates a popular IDE interface standard that was available back in the 1990s, Ease of Use does not come configured for that.

Michael Furman to the rescue

Enter Michael R. Furman and his GitHub page. He has taken time to create scripts that will make XRoar compatible versions of the Ease of Use releases. Even better, he has the complete .DSK images available:

https://github.com/n6il/eou_ide/releases

Even though I find XRoar the easiest of all the emulators to get going, it still has its own learning curves. I present this step-by-step tutorial on how to get NitrOS9 Ease of Use up and running in the XRoar emualtor.

Get NitrOS9 Ease of Use up and running in the XRoar emulator.

  1. Download the XRoar version for your system.
    https://www.6809.org.uk/xroar/
    (This tutorial will not cover the steps needed to do this on Raspberry Pi.)
  2. Download ROM images for XRoar, specifically one for Color BASIC and one for the CoCo 3.
    1. Download “bas11.romhttps://colorcomputerarchive.com/repo/ROMs/XRoar/CoCo/BASIC_OS/
    2. Download “coco3.rom“. You can find it inside the coco3.zip file here (and you’ll need to unzip that to get the coco3.rom file). https://colorcomputerarchive.com/repo/ROMs/Jeff%20Vavasour/
    3. If you want to use XRoar for general Color Computing, you will also want “extbas11.rom” and “disk11.rom” — but they won’t be needed for NitrOS9.
  3. Download Michael Furman’s Ease of Use IDE version for the 6809:
    https://github.com/n6il/eou_ide/releases
    Look for the one named “eou_ide-6309-bin-v0.3.zip” (or a later version if there is one).

Some assembly required. Just not the programming kind.

Now you have all the components you need. You just need to put them together, and create an XRoar configuration that will set up appropriate defaults.

There are many ways to do this, but we’ll keep it simple.

  1. Make a directory: Create a directory/folder that you want to use for running XRoar out of. You might make “XRoar” on your Desktop, or in Downloads or whatever you prefer.
  2. Copy XRoar binary in to it: From the XRoar download .zip file, copy the binary (xroar.exe for Windows, xroar.app for Mac) in to your new XRoar directory.
  3. Copy ROM files in to it: Copy the rom files you downloaded (bas11.rom and coco3.rom) in to your new XRoar directory.
  4. Copy the Furman files in to it: From the Michael Furman eou_ide download .zip file, navigate in to “6809_ide_xroar” directory and copy 68IDE.ide and hdblba.rom in to your new XRoar directory.

With the ROMs in the same directory as XRoar, you could run XRoar right now and it would default to emulating a 64K Color Computer 1/2 model. We want it to load up in CoCo 3 mode, using a special boot ROM (so no boot floppy is needed) and the hard drive image.

This can be done by command line options (ick) or by creating an “xroar.conf” text file with the settings we want. Save the following text out to  a text file called “xroar.conf” in your new XRoar directory:

xroar.conf

machine coco3
tv-input rgb
machine-cart ide
cart-rom hdblba.rom
load-hd0 68IDE.ide
kbd-translate
default-machine coco3

With all those files collected, you can now run xroar.exe (or xroar.app on Mac) and you will boot in to a virtual Color Computer 3:

XRoar emulator, CoCo 3 mode with IDE hard drive boot ROM.

PERMISSION NOTE: Some operating systems will warn that this program is not recognized. You will have to take additional steps to make it run the first time.

“Windows Protected your PC”
“Windows Protected your PC” … but let’s run it anyway…

Welcome to NitrOS9 Ease of Use Edition

From this glorious green screen you can type “DOS” to boot in to NitrOS9 Ease of Use edition.

XRoar emulator running NitrOS9 Ease of Use edition.

Type in the date and time (NitrOS9 has been updated to be Y2K compliant) and after a bit more loading, you will be at the wonderfully cryptic OS-9 command line prompt (called the shell).

Once the colors are properly set, if you want to go in to the 1980s GUI, type:

gshell

The colors will look awful. Gshell defaults to settings for composite/NTSC TV output, and we have XRoar emulating an RGB monitor. GShell also needs a mouse/joystick. To change this, you will want to enable joystick by going to the XRoar menubar and selecting “Hardware -> Right Joystick -> Mouse

Now that you can use the mouse (pay attention to the mouse drawn by GShell, and not your Windows/Mac computer mouse pointer), click on the “X” looking icon (I think it’s supposed to be the old Radio Shack Tandy logo) to open the menu:

XRoar emulator showing TV colors on an emulated RGB monitor. Ick!

From there, you can select “Control” and then change your monitor type to RGB and SAVE. Things should look much nicer now.

XRoar emulator GShell control panel.

You can dismiss the Control panel using the top left square box icon, and save your changes.

You could then go to “View -> 80×25-4 (FAT)” (in the emulated CoCo, not the View menu of XRoar) and switch to the high resolution mode.

XRoar emulator with NitrOS9.

…and to learn about what all you can do, check out the official Ease of Use website:

http://www.lcurtisboyle.com/nitros9/nitros9.html#currentdownloads

Conclusion

It’s as easy as “drop 6 files in a directory, run the emulator, and type DOS.” … then … profit?

Have fun!

In 1982, I received my first computer: a $299.99 Commodore VIC-20. A year later, I moved on to a 64K Radio Shack Color Computer ("CoCo"). In 1990, I co-founded Sub-Etha Software "in Support of the CoCo and OS-9". This later led me to a job at Microware, creator of OS-9. I am author of the CoCoFest Chronicles, a compilation of my fest reports covering the 1990s era. I also host the CoCopedia.com wiki. These days, I am enjoying excavating my original VIC-20 tapes and thousands of CoCo floppy disks...

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