Task: Run the CP/M Operating System on Your Atari 8-Bit Computer using FujiNet and RunCPM
Needed: Web browser, FujiNet, DT-80 cartridge
Time: 15-30 mins
CP/M was one of the early operating systems available for computers with 8080 and Z-80 processors. It was developed by Gary Kildall and first released in 1974. It came close to becoming the dominant operating system, but was overtaken by DOS. Regardless, CP/M was quite popular through the 1980s on many Z-80 based computers and was even accessible on the Apple II through a Z-80 card and the Atari 8-bit computers via the ATR8000 peripheral. One of its advantages was that it allowed multitasking.
There are three ways you can access CP/M from an Atari 8-bit computer. The first is through the ATR8000 which is essentially a Z-80 computer using the Atari as a dumb terminal. Unfortunately, the ATR8000s are difficult to find and a bit inconvenient because you also need a standard disk drive to boot CP/M software. I have one and plan to do a post about using it at a later time. The second is through a modified Indus GT floppy drive which has a built-in Z-80 processer. The third and much easier way to play with CP/M is through FujiNet which I have previously posted about. FujiNet is an SIO peripheral emulator and network device which opens many doors for booting files, communicating over the internet etc. The key to using FujiNet to run CP/M is the ESP32 microcontroller unit (MCU) which is compatible with a CP/M emulator called RunCPM. RunCPM is now included in the latest firmware updates for the FujiNet. Below are instructions for booting CP/M from your FujiNet device.
Before you read my instructions, you should read the FujiNet CP/M support page.
The first step is to purchase a FujiNet. I have previously posted those instructions.
The second step is to purchase a DT-80 80-column cartridge for CP/M from the Vintage Computer Center. CP/M needs 80 columns and this cartridge provides that functionality. Further, the CP/M version includes the CP/M terminal program that the Atari needs to act as a dumb terminal. You will need to this cartridge to boot CP/M and see it in 80 columns. These are expensive and run around $70. Note that you might be able to avoid this step by using an 80-column terminal program like ICE-T. I haven’t tried this yet but might be worth exploring before you drop $70.
The third step is flash the firmware of your FujiNet to make sure it has the latest version with RunCPM included.
The fourth step is to set up the FujiNet SD card with a CP/M directory and files. Create a folder called CPM in the root of the SD card. Within that folder create folder called A. Letters refer to disks in CP/M. Within A create a folder labeled 0. Numbers are treated as users in CP/M. Within folder CPM/A/0/ unzip the CP/M files from this zip file. Place the SD card back in the FujiNet.
The final step is to boot CP/M! Plug in the FujiNet and the DT-80 CP/M terminal cartridge. Boot your Atari. Once the DT-80 cartridge is booted it will send a set of commands to the FujiNet to start CP/M. You should see the RunCPM command prompt appear as pictured below. Type DIR to see the list of software available from the zip file (see below). Many of these are commands for interacting with files, etc. as you might expect from a DOS.
Note that 80-columns is hard to see on some CRTs. The best CRT monitors for this purpose are monochrome. The screenshots are photographs of an LED screen with video signal coming from my Atari 800XL with the UAV modification converting composite to S-Video and then S-Video to HDMI using a RetroTINK. I can read the screen quite clearly.
I was so excited to be able to run CP/M on my Atari without an ATR8000. This is an amazing development. Thanks to the FujiNet team for making this happen.