OS-9

Introduction

The FNX6809 combined with the F256 makes a great system for running OS-9/6809. OS-9 is a real-time, embedded operating system created by Microware Systems Corporation. While it was used in many areas of industry, home computer users know it best for its implementation on the Tandy Color Computer sold by Radio Shack

Today, a community effort has led to the creation of NitrOS-9, an open source version of the OS-9 operating system. Throughout this page, I'll refer to NitrOS-9 as OS-9.

A word about platforms

This page assumes you're running on Linux or macOS. If you're using Windows, these instructions don't apply, and someone will have to step up and write steps to develop on that platform.

Tooling

Cross-hosted development is the fastest way to develop for the F256. For this you need the following:

• lwtools - an assembler/linker package
• ToolShed - a set of tools for creating disk images
• NitrOS-9 - the NitrOS-9 operating system in source form
• FoenixMgr - tools to load code into RAM or Flash of the F256.

You can pull these down individually, or better yet, use @strickyak's great CoCo Shelf repository. It has a Makefile which gets all of the above and puts it in a convenient location (note that you'll have to update your shell script of choice to include the locations of the binaries in the PATH environment variable).

Here are the terminal commands for Linux and macOS to pull down all the required software:

cd
git clone https://github.com/strickyak/coco-shelf.git
cd coco-shelf
export PATH="$PATH:$HOME/coco-shelf/bin"
make ANON=1 nitros9/done FoenixMgr/done

(If you have a github account and your github ssh key is loaded, you can omit `ANON=1` on the last command, so it will check out git repositories using your github username, in case you want to push changes.)

There is a special Make target for re-flashing the F256 Jr, but first time you run this command, it should fail. Then you have to edit the `port=` line in `FoenixMgr/foenixmgr.ini` and run the command again (with the cable plugged in):

make ANON=1 run-f256-flash

Building FEU and OS-9 Level 1 from scratch

FEU is the Foenix Executive Utility. It resides in flash and hosts a debugger and booters that can bring up operating systems like OS-9. FEU runs under OS-9 Level 1, so go ahead and build the entire operating system:

cd nitros9
export NITROS9DIR=$PWD
cd level1/f256
make 
cd feu

Now you can flash the image into the F256. You must have a USB cable connected to the system from your computer. Note: if you're using a Mac, you won't be able to upload code into the F256 due to the driver manufacturer being so behind on updates. You can use a Linux VM and FoenixMgr tools in bridge mode on the Mac.

There are distinct builds of FEU for the F256 Jr and the F256K. Power up the machine, then select the correct command:

cd feu
make flash_f256jr

or

cd feu
make flash_f256k

Once the flash completes, restart the machine and FEU should come up.

Building OS-9 Level 2

To build OS-9 Level 2, run these commands:

cd ../../level2/f256
make dsk

This produces the following disk images for the F256 Jr and the F256K:

NOS9_6809_L2_v030300_f256jr_dw.dsk
NOS9_6809_L2_v030300_f256jr_sd.dsk
NOS9_6809_L2_v030300_f256k_dw.dsk
NOS9_6809_L2_v030300_f256k_sd.dsk

The dw disk images are for booting from DriveWire. The sd disk image are for booting from the SD card. You need to write the images onto an SD card, then insert the SD card into the F256 and restart.

Here's how to image the SD card.

Linux

On Linux, insert the SD card into your computer. Ttype lsblk to find the correct device and replace sdx on the command line below with it:

dd if=NOS9_6809_L2_v030300_f256k_sd.dsk of=/dev/sdx

macOS

On macOS, insert the SD card into your Mac. A dialog will likely appear telling you that the disk you attached isn't readable. Click the "ignore" button, then type diskutil list external to obtain the device name of the SD card and replace diskx on the command line below with it:

sudo dd if=NOS9_6809_L2_v030300_f256k_sd.dsk of=/dev/diskx

Once the command completes, type:

diskutil eject /dev/diskx

You can then safely remove the SD card.