TRS-80 Color Computer Commands:

These are general O/S (RSDOS) commands (not OS-9):


0 - the first floppy drive.

1 - the second floppy drive.

file.bas - BASIC program.

file.bin - Machine language program.

To load a machine language program called "file.bin":

To execute (start) a machine language program:

To load a BASIC program called "file.bas":

Run the BASIC program by typing:

To run an autoexecuting BASIC file:

List the files and directories on a disk:

To change to drive 3:
drive 3

To format the disk in drive 0 :

To list the lines of a BASIC program in memory:

Deleting a file named FILE.EXT:

To copy "file.ext" to drive 1
copy"file.ext" to "1:file.ext"

To rename a file:
rename"file.ext" to "myfile.ext"

Clear the screen:

Copying the disk in the first floppy drive to the blank disk in the second drive:
backup 0 to 1

Load a file from tape:

Save a fle to tape:

Double the MHz rating of your CoCo II (overclock command):
poke 65495,0

Set the MHz rating of your CoCo II back to normal:
poke 65494,0

Getting an OS9 game running:
Insert an OS-9 disk (we'll use the game Rogue as an example), and type:

Then type
rogue -x


File system error messages:

I/O - Input/Output error
SN - Syntax error (incorrect BASIC or disk command -- spelling error)
TM - Type mismatch (or incorrect contextual use of a disk command)
DF - Disk full
NE - Non-Existant file (the file you asked about is not on that disk)
WP - Disk is write-protected


CoCo III Commands:

To change the video mode to its inverse:

Double the MHz rating of your CoCo III (overclock command):
poke 65497,0

Set the MHz rating of your CoCo III back to normal:
poke 65496,0


CoCo II - 64K RAM
- 6809 Motorola CPU 16-bit internal ; 8-bit external architecture.
- 9-color palette. 4 colors at a time.
- max res of 256x192


CoCo III - 128K or 512K RAM
- 68B09E Motorola CPU 16-bit Internal ; 8-bit external architecture.
- Additional registers, and faster operational speeds (more transistors).
- Max Resolution of 640x200 in 4 colors. 320x200 16 colors. Palette of 64 colors.

More powerful operating systems are OS-9 Level 1 and 2, by Microware.
(OS-9 is a pre-emptive multitasking O/S, and has a bit of a cult following).
Newer versions of OS-9 are currently used for industrial/robotics purposes.
Note: This has nothing to do with MacOS.


So you'd like to learn to program in BASIC. Or maybe you just want to
play around with an old-skool Tandy Color Computer. Well, here's everything
you need to get started:

ColorComputer2.7z Tandy Color Computer 2 emulator and extras for the PC
(Win98se, 2000, XP, 7,...). Audio, joystick, and 5.25" drive support possible in Win98se.

And here's the Tandy Color Computer 3 emulator:


Some info on how to get Atari video game controllers running on a Tandy:

The insides of a Wico analog to digital joystick adapter.

Schematic posted by a hobbyist.