This is a project to emulate GPiB peripherals for the GRiD Compass computer.
BlackGPiB can emulate a hard drive and a floppy drive. It also has a printer and plotter proxy. Current version is based on Raspberry Pi 3 or newer. Support for Raspberry Pi 2 is not implemented due to the need to adapt the code for armv6.
A new version for Raspberry Pi Pico is already in development.
For more information about device emulation, see the Details About Emulation section.
There is no illustrated guide, and there won't be one until a new version of the board is developed. If you are interested in assembling a prototype, you can find the board project files and their description in the hardware/ folder.
For stable work please setup a real-time (RT) kernel on your Raspberry Pi. Otherwise, sometimes the emulator may sometimes hang and the Compass will show timeout errors.
To build kernel please read official instruction from Raspberry Pi: https://www.raspberrypi.com/documentation/computers/linux_kernel.html.
Before building, check the "Configure the kernel" section and enable Real Time mode. You'll need to select "Fully Preemptible Kernel (Real-Time)" in menu "General Setup" -> "Preemption Model".
To build the project, you need to install the latest Rust compiler.
Then, just run:
make build
After this, the binary file will be created at target/aarch64-unknown-linux-gnu/release/blackgpib.
Copy this file to your Raspberry Pi and try it.
For a detailed description of how to use BlackGPiB, run the program with the -h option.
The disks with the operating system and instructions for making your own disks are in the disks/ folder.
The GRiD Compass does not see any difference between a floppy drive and a hard disk. For the computer, both are just "block devices".
BlackGPiB can emulate disks for reading and writing at all standard addresses: 4, 5, 6, 12, and 13. Disks at non-standard addresses are not supported (for now).
The emulator doesn't support all known commands, only the most essential ones: Initialize, Status, Read, Write, and Format.
BlackGPiB can emulate a printer and a plotter. It connects to the right addresses and sends everything from the laptop as UDP broadcast to 49275 for printer and 49276 for plotter.
A proxy for CUPS or any other system is not part of this project and will not be added to this repository.
You can make your own proxy if you like:
🖨️ For the printer proxy, we recommend using the Epson MX-82 driver and making your own converter for ESC/P commands.
🖊️ For the plotter proxy, you need to make a converter from HP-GL (not HP-GL/2) to something else. The commands from the laptop may be different from the standard, so please use documentation for supported plotters.
This project would not have been possible without a whole group of amazing people.
Huge thanks to Kirill @BOOtak for first telling me about this laptop, reverse-engineering the file system, and providing support throughout the entire project.
Many thanks to Anton @usernameak for the GRiD Compass emulator in MAME and for carrying out the main work on reversing the communication protocol between the laptop and peripherals.
Big thanks to @JDat for reverse-engineering the GRiD Compass, making the first version of the board, and providing a huge amount of advice during the project.
Special thanks to Kirill from the Belgrade hackerspace Xecut for his help, for providing equipment, reviewing the project, and overall participation.
And many thanks to Vladislav @Bs0Dd for the graphical interface for working with the disks — it made things much easier.