PiDP-8/I SoftwareOS Compatibility
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The Situation

Although the core software underlying the PiDP-8/I software distribution is broadly portable, the dominance of Raspbian in the Raspberry Pi space means it gets the most attention when it comes to testing and development. This article documents what it known to work, where, today.

If you need the software to work on some platform where it currently doesn't, we accept patches! You can also send problem reports to our development forum, file a bug report, or discuss it on the users' mailing list.

Debian & Derivatives: Raspberry Pi OS, Ubuntu...

All instructions given for the PiDP-8/I software assume that you're running a Debian derivative where not otherwise stated. This is because the software is primarily designed to run on Raspbian, the official OS for the Raspberry Pi.

The trunk version of this software successfully runs on Raspbian Buster (v10), released in early July 2019. It should also run on its renamed successor, Raspberry Pi OS, though that is not currently tested. We haven't made a release atop these OSes yet, so consider this a "beta" configuration for now.

The current stable release of this software was built for and tested with the Raspbian Stretch Lite (v9) distribution. The software should also work well on the non-Lite version.

Prior releases were built atop the Raspbian Jessie Lite (v8) distribution, but somewhere along the line, we broke compatibility with Jessie. If you need to keep running on Jessie, which is now out of support, we recommend that you run version 2017.04.04 of the PiDP-8/I software, the last version specifically tested atop Jessie.

Raspbian-based OSes like pipaOS should also work, but this is not tested by the project's current developers.

The project's primary maintainer occasionally builds the software on x86 Debian derivatives, which works fine, since Raspbian is a Debian derivative. On such systems, the software detects the absence of the PiDP-8/I front panel hardware and works without it.

Devuan

There is one major exception to the rule that the software works on Debian derivatives. After Debian (and thus Raspbian) moved to systemd many years ago, we transitioned to it as well. Thus, the current software does not run out of the box on Devuan, a Debian derivative that purposefully removes systemd. You can recover the old SysVInit script from the software repo with:

$ fossil revert -r 27f585bd1b etc/pidp8i-init.in

You will then have to make the following manual substitutions in the file:

@VARIABLE@ Standard replacement
@ABSPREFIX@ /opt/pidp8i
@BOOTDIR@ /opt/pidp8i/share/boot
@INSTUSR@ Either pi or pidp8i

Copy the resulting file to /etc/init.d/pidp8i, then commands like sudo service pidp8i start should work.

Non-Debian Linuxes

There are non-Debian type Linux based OSes for the Raspberry Pi such as openSuSE for the Pi 3 and CentOS for the Pi 3. Since the primary developers on this project haven't tried any of these Pi Linux distros, and no one has reported on their attempts to make it work, we can only speculate on the workarounds required, if any.

Off the Pi, pretty much every Linux distribution should be able to build and run our software, once you've installed all of its prerequisites. We've built and run it successfully a few times on 64-bit Intel boxes under CentOS, for example.

macOS

This project's current primary maintainers use macOS at home, so the PiDP-8/I software is frequently built and tested on macOS while we are working on features that do not require the PiDP-8/I front panel hardware.

Why? Because it builds many times faster than on a Pi, depending on what has to be built!

Stock macOS doesn't have everything you need to make it work. We recommend installing Homebrew, then using that to install the third-party dependencies that the PiDP-8/I software needs.

FreeBSD

Because of our regular testing on macOS, the software works well on x86 FreeBSD.

On FreeBSD 12, you need the following prereqs:

$ sudo pkg install coreutils gmake perl5 python py37-pip

Note that this gets you Python 3, which currently only works with the trunk release of the software. The current stable release only works with Python 2, which was the default version on FreeBSD 11 and older.

The configuration process will fail if you do not give the --prefix option because /opt isn't present on FreeBSD by default. Rather than create that subtree, a more "native" FreeBSD configuration would be:

$ ./configure --prefix=/usr/local/pidp8i

There is a FreeBSD build for the Pi, but we believe it will not work with the front-panel hardware. You are more than welcome to fix this and [send us a patch].

Windows

The PiDP-8/I software's build system requires a POSIX type environment. There are several ways to add that to Windows:

Linux VM

Currently, for maximum compatibility, your best option is to install some sort of Linux virtual machine on your Windows box.

Windows 10 Pro and up include Hyper-V, which runs Linux VMs quite well.

For those running Home class versions of Windows, the best free option is Oracle's VirtualBox.

Cygwin

This works, and appears to work well besides in the multiple times we've tried it. The most recent test was on 2019.05.11 with 64-bit Cygwin 3.0.7 on Windows 10.

You will have to install the libncurses-devel and python2-pip packages as well as standard Unix build tools: GCC, GNU Make, etc. Having done all that, the software will build and run.

For bin/pidp8i to run properly, you need to run the trunk version of our software: the systemd improvements made to it for the most recent stable release don't work under Cygwin, but we've fixed that on trunk.

Windows Subsystem for Linux

Terminal emulation and pty handling have been a longstanding problem with WSL, and there were still bugs in it the last time I tried it, on 2019.05.11 with 64-bit Windows 10 Pro 1803 running Ubuntu 18.04.02 LTS. It's much better than the tests we conducted back in 2017, however.

These problems mainly show up when running the simulator under GNU screen, as our bin/pidp8i wrapper does. In my latest attempt, the following would result in a "dead" screen session:

$ pidp8i start      ← start simulator under GNU screen
$ pidp8i            ← attach to screen session
Ctrl-A, d           ← detach; leave it running
$ pidp8i            ← reattach; reports it "dead"

You can avoid these problems by running the simulator directly:

 $ make run
 $ bin/pdp8 boot/0.script

...and so forth.

It is possible that the improvements announced at Build 2019 to WSL 2 and the Windows console will solve these remaining pty and terminal emulation problems. Until they're addressed, the above choices are better options.

As with Cygwin, there are portability fixes on trunk now that are not yet released.