Steam on Chrome OS explanation makes hope for easy modding

One of the most interesting things about covering Google’s technologies and products is how communicative the company can be when explaining how things work. It recently launched the first part of a planned series that shed light on how it got Steam for Chromebooks. In this first high-level overview of the technologies involved, a key fact has already been detailed: Changing games (even just to adjust configuration files) can be quite difficult, if not impossible.

As usual, Chrome OS ❤️s are virtual machines (VMs), and they’ve a big part of how Steam works on Chromebooks. If you remember sites like ours that toss around with the name “Borealis” referring to Steam, it’s the name of the World Cup image that Steam runs in (which is based on a modified version of Arch Linux, and probably a nod to Aperture The Science ship referenced in Half-Life 2: Episode two). This VM, like Chrome OS’s other VMs, keeps things simple and secure – everything you need for Steam to work is contained right there in the VM, it can be installed (and uninstalled) at once, and it never has access your files or system directly. Google even built its own Vulcan virtualization driver to reduce the performance associated with using a World Cup for gaming.

World Cups are store for security, but along with what else we know about how this works, it can give a little headache to gamers hoping to install mods or even just tweak their games to work better on their Chromebook.

To increase security, the VM image is used in a read-only mode and is subject to validation. Our own test shows that this includes some form of verification to ensure that it has not been tampered with. I’m told by the AP’s Kent Duke that it’s ‘so tight that even updating to a platform higher than what DLC expects (ie from Dev to Canary) prevents the VM from booting,’ and the software tools , it has, are limited. (For those in Linux know that you can not install software for the VM via tools like Pacman, there is no Sudo, su is locked and text editors are not available.)

Taken together, these limitations mean that, as far as we know right now, there is no way to write to the World Cup image to make changes to game files. Moreover, even if you were somehow able to change the contents of the VM and the game files through some form of exploitation, it is almost certain that you would ruin the Steam VM completely by doing so.

This may sound like a very “whatever” issue that only hardcore game modes hoping to add Thomas the Tank Engine to Skyrim would worry about, but there are actually plenty of reasons why you might want to change a game’s configuration files . Often, developers will gather additional non-user-facing settings in separate configuration files that can help you achieve slightly improved performance – handy when playing on underperforming hardware (which Chromebooks sometimes qualify as). Chromebook hardware also varies widely when it comes to things like screen density, and games are not always built to take such details into account. It can sometimes be solved by adjusting a game’s configuration files or starting it with a specific parameter attached, if there is no user-facing setting for scaling in the game itself, but that is not possible here.

Of course, games themselves can solve that kind of problem in their own ways by loading menus with additional options, but that’s unlikely. This restriction removes one of the tangible benefits of “PC” gaming – even on a Chromebook. Solutions may have yet to be discovered, and some of us here at Android Police have dug to see what is possible within the constraints of the World Cup framework.

This probably will not directly kill mods for games on Chromebooks, as Steam has mods support through the Steam Workshop, but it does mean that you may not have all the same modding freedoms that you would have on a “normal” PC, when it comes to game tweaking – at least until someone finds a way around Borealis’ verification system.

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