NitrOS-9 The best operating system for the Tandy/Radio Shack Color Computer ever.. and it's free!

Mini How-Tos

Access your NOS-9 system from a PC
From an email sent by Chester A Patterson to the CoCo list.

First time around I went through the bit-banger and that slowed down the Coco something awful. Now with the RS232Pak it's a different story, no discernible drag.
I use the Windows98 Hyperterminal. It is the handiest one for me. And has those neat assignable buttons.
/T1 is your serial port on the back of Coco (the "bit-banger"). /T2 is a RS232Pack in slot 1 of the MPI, and /T3 is a RS232Pak in slot 2 of the MPI.
Pick one. Gotta make certain that the RS communications are the same at both the Coco and the WinTerm. I use 9600-8-N-1. Flow control via software.
Make certain that your cable does what it's supposed to, a nul-modem adapter can come in handy.
Finally, when all is connected and configured, you do a "shell = /t2&" from the OS9 prompt (I put it in startup) You should get an OS9: prompt on your Hyperterminal window. So it works just like another text window.
I don't really use it. I just wanted to test the RS232Pak I bought, and I was working out how to transfer files back and forth but ended up using VCC and the MESS Image Tool instead.
I think that's about it.
Good luck!

From an email sent by Bob Devries to the CoCo list.

It's possible to get fairly creative with the ON..GOSUB and ON...GOTO commands in Basic09 in conjunction with the SUBSTR command.
Here's how:

The SUBSTR command returns the numeric position in a string of the source string, so you could end up using something like this:

PRINT "Enter Y or N"
INPUT answer
num = SUBSTR(answer,"YyNn")
(* getting more creative here... error trapping!
(* add one to the number in case your user didn't type either Y or N... in which case num would be 0
ON num+1 GOTO 10, 20, 30, 40, 50
10 PRINT "WRONG! Please type Y or N"
20 PRINT "You typed 'Y'"
30 PRINT "You typed 'y'"
40 PRINT "You typed 'N'"
50 PRINT "You typed 'n'"

It's possible to combine two lines above like this:

ON SUBSTR(answer,"YyNn")+1 GOTO 10, 20, 30, 40, 50

Note that you MUST have a line number in the ON...GOTO command for each possible outcome of SUBSTR.

Transferring DSK Images to Floppies

NitrOS-9 releases contain two 40 track double-sided images or one 80 track double-sided image. In order to transfer these disk images to a floppy disk suitable for use on a CoCo disk drive system, a 5.25" 360K floppy drive and/or 3.5" 1.44MB/720K floppy drive is recommended. The 1.2MB 5.25" floppy drive variants may seem to work, but will cause problems when being written on a CoCo system, so they are not recommended. New and refurbished 5.25" 360K floppy drives can be obtained from Cloud-9.

Windows 9x/DOS

For the example below, we will assume that the 3.5" 720K floppy drive is A:, and the 5.25" 360K floppy drive is B:
The tool required to transfer DSK images to floppies under DOS/Windows is DSKINI.EXE.

Once DSKINI.EXE has been downloaded and extracted, call up a Command Prompt window under Windows (if you're not using MS-DOS), and insert a blank 5.25" 360K diskette into drive B. Presuming the image being transferred is nos96309l2v030200_ds40_1.dsk, type:
DSKINI /T40 /D B: NOS963~1.DSK
Note the use of the mangled filename form here. If you are running Windows, you can type the full length filename.
Once the transfer completes, you should have an exact image of the disk on the floppy, and can now use that floppy on a real CoCo.


For Linux users, download the fdutils 5 package at
Once installed, insert a blank floppy into your 5.25" 360K or 3.5" 1.44MB/720K drive. It will be either /dev/fd0 or /dev/fd1 depending on its position in the drive chain. For this example, we will assume /dev/fd1.
First, you must edit the file /usr/local/etc/mediaprm and add the following lines at the bottom of the file (you will have to edit this file as root):
DS DD sect=18 cyl=40 ssize=256 tpi=48

DS DD sect=18 cyl=80 ssize=256 tpi=96

Once this is done, you must tell Linux the type of disk in the drive. You must do this EVERY TIME you insert a disk into the floppy drive, as Linux "forgets" the disk type when you take the disk out:
setfdprm /dev/fd1 coco40ds
Now you can format the disk:
fdformat /dev/fd1
Once the format is complete, transfer the image as follows:
dd if=nos96309l2v030200_ds40_1.dsk of=/dev/fd1
Once the command is complete, the disk will contain the image and can be used in a CoCo disk drive system.

Windows 2000 / XP / Vista

Since this OSs don't allow direct access to the hardware, Fdrawcmd.sys , a special driver is needed.
After installing it, download CoCoDisk .
This program is quite simple to use.
First, it's a good idea to format the floppy. Use the Double Sided, 40 or 80 tracks option, according to the DSK file you are working with.
After formatting, just select your destination drive, "Write image to disk", and click on [write...] to point it to the DSK image you want transferred to the floppy.