Guide: Parallel port passthrough in Proxmox VE 8.3.1

Why?

Recently I have been messing around with a 30+ year old film recorder, which runs over parallel on Windows 95/98.
I don't have the space to dedicate a vintage PC to it, but I do have a low power Proxmox server with a parallel port!

However, there's fairly little documentation online about passing parallel ports through to a VM.
I was only able to find one slightly confusing thread from 2009 on the PVE forums!

So, here's a nice clear guide on how to do it!

Prerequisites:

• A Proxmox 8 server with a parallel port
  Honestly, this will probably work on any version, but I used PVE 8.3.1 running on an Asrock N3050B-ITX board.
• PuTTY, or whatever SSH client you're used to
• Physical access to said machine
• A keyboard and monitor

 

Disclaimer:

Follow this guide at your own risk!
I am not responsible for any mistakes, explosions, dead film recorders, or anything else!

That said, I have done my best to ensure this guide is as accurate as possible, and these instructions did work for me!
(if I did make a mistake though, please contact me, and I'll fix it!)

However, I will not provide any support, so be warned!

 

1: BIOS Setup

Go into the BIOS or UEFI of your chosen server, and find the setting for "Parallel Port Mode".

For my board, that was under Advanced > Super IO Configuration.

Make sure the parallel port is enabled, and that it's in ECP+EPP mode.
The version of this mode doesn't really matter! (mine has 1.9 and 1.7)

Then, save and reboot into Proxmox.

 

2: Proxmox Setup

Open an SSH connection to your Proxmox host (not to a VM!), and login as root.

Then, check that Proxmox can see your parallel port with the following command

dmesg | grep parport

That should return something like this.

If it doesn't, double check your BIOS settings then try again.

Next, use this command to enable Proxmox' parallel port kernel module, ppdev.

modprobe ppdev

To make sure that it's enabled, run

ls -la /dev/parport*

You should now see something like this :)

Now you'll need to make sure that module is loaded at every boot, by adding it to /etc/modules.

Open /etc/modules in your favourite text editor (I used nano), then add ppdev on a new line.

nano /etc/modules

Save (ctrl+O in nano), exit (ctrl+X), and reboot your Proxmox host.

reboot now

Finally, to make double sure that it's enabled on boot, run this again after Proxmox has rebooted

ls -la /dev/parport*

You should see exactly the same output as the first time you ran it :)

If so, you're now ready to pass it through to a VM!

 

3: VM Setup

To pass the port through to a virtual machine, just run this

qm set 100 -parallel /dev/parport0

Replace 100 with the ID of your virtual machine!

Make sure the VM isn't running!

I've only tested this with i440fx/SeaBIOS type VMs, but it'll probably work with q35 too.

Now start/restart your chosen VM, and check to see if the port is available.

and that's it, you are now ready to print like it's 1995!

 

Also, if you're interested,
I'll be doing a full project post soon about getting my film recorder running, so keep your eyes peeled over at nycto.io!

Happy printing! (or film recording!)