The latest version of System76's Ubuntu remix is available, but it's not finished by any means. The new Rust-based desktop is somewhat usable, though.

US shifter of Linux boxes System76 has released alpha 1 of Pop!_OS 24.04. It's the company's remix of Ubuntu Noble Numbat, with its own in-house ground-up desktop environment, codenamed COSMIC and implemented in Rust. The result is a new and incomplete desktop, running on top of a fairly stable and mature OS. Some parts are still missing and we saw some occasional but repeatable app crashes, but it's usable if you're patient. It has already received some rave reviews, but we think it will sharply polarize users.

Pop OS is a relatively new distro: the first release appeared in late 2017, and the Reg FOSS desk has looked at it a couple of times: first at version 21.10, which caused us significant problems, and later at the next LTS release, version 22.04 which proved less troublesome. As an Ubuntu remix, it makes some interesting but not all that profound changes under the covers. What's interesting about this release in particular is its new desktop environment, COSMIC. This has been a long time coming - the Register covered the plans way back in 2021. A few years later, we have a preliminary version to try out.

First, let's look at the OS part. There aren't too many radical changes here: it is based on the most recent Ubuntu LTS, and while its development team is busily building a new desktop, the distro stopped doing interim releases: this is the first version since 22.04. System76 removes Canonical's Snap packaging format, and replaces it with Flatpak. On UEFI machines, Pop OS replaces the GRUB bootloader, used by Ubuntu, Debian, and most other distros, with the systemd-boot bootloader. This keeps the Linux kernel and initrd in the UEFI system partition (or ESP for short), which is unusual but forms an initial step in the direction of systemd supremo Lennart "Agent P" Poettering's plans for Unified Kernel Images. This means you need a much bigger ESP than standard, but that won't be a problem on a clean install. We tested in VirtualBox, and Pop!_OS 24.04 created a whopping 1GB ESP. It also drops LibreOffice and a few other familiar apps, but you get Vim pre-installed, a tool for creating bootable USB keys, and a few other extras.

Pop OS does make some slightly unusual configuration choices under the hood. The setup program defaults to enabling full-disk encryption, using the same password as the user account, but you can untick the option. Even so, we got a dedicated swap partition, also encrypted with cryptsetup, as well as compressed swap in RAM using the zram memory-compression tool. This seems overly paranoid to us: if the user disables disk encryption, we'd prefer to see a plain old swap partition with zswap compression enabled, which we've found gives useful performance improvements on heavily-loaded desktops. We disabled both ZRAM and cryptsetup, but this left annoying messages during bootup about the latter.

Enabling Zswap is normally as easy as adding a line to /etc/default/grub - but of course that doesn't work when the distro doesn't use GRUB. It's easily done with the new kernelstub command, but it's the kind of small, troubling difference from stock Ubuntu that will trip up experienced users. Expect to resort to Google frequently at first. Luckily this works well, as Pop OS is one of the more popular distros out there among the sorts of folks who eschew beginners-focused distros such as Linux Mint or Zorin OS, but who weren't overly influenced by Mr Robot into wanting to run Kali Linux and thus boost their elite hacker credibility.

But the visible part is, of course, the shiny new desktop. Before embarking on its Rust adventure, System76 shipped a heavily customized version of GNOME, which the team also called COSMIC. Aside from a different app store and different, but stylish, cosmetics, probably the defining feature of COSMIC GNOME was its tiling window support. Tiling window managers are noticeably trendy in recent years, to the extent that GNOME itself weighed it up. Most are aimed at command-line folks, though, who typically don't want GUI fripperies such a file managers, calculators, text editors and what not: they have their own preferences in such things.

Since version 3, GNOME has had a simplified interaction model, with no minimize and maximize buttons: instead, it urges you in the direction of lots of full-screen windows, each on its own virtual desktop. This is not at all to the tastes of this cynical old reporter who acquired window-management muscle memory in the 1980s and still works much the same way. As such, we were pleasantly surprised by COSMIC: it improves upon GNOME's very basic window-management tools, while retaining a good-looking desktop and some familiar tools.

As you might expect from a company which shipped a GNOME-based desktop for six years or so, the new COSMIC is strongly reminiscent of GNOME. A little like Elementary OS's Pantheon desktop, it has a mostly-empty top panel and a dock-like launcher at bottom center - neither based on GNOME code. The result resembles GNOME Shell from a few years ago. There's a clock in the middle, seven status icons at top right, and a couple of textual buttons at top left. GNOME has combined all its status icons into one macOS-like "quick settings" control, but COSMIC keeps them separated, which we prefer. There are controls for keyboard layout, window tiling, volume, networking, power, notifications, and session management.

Overall, it's very different from rivals such as Cinnamon, or Zorin OS's extension-based GNOME environment. They both reshape GNOME into something that's intentionally much more like the Windows desktop. Even the Budgie desktop uses some GNOME components to build a simpler, faster, Windows-like desktop. We also thought it might be akin to Ubuntu's Unity, which imported some GNOME components - such as the file manager - wholesale, but rewrote the desktop into something more like Mac OS X but controlled with Windows keystrokes.

COSMIC goes the other way. It looks much like GNOME, it works rather like GNOME, but aside from a few accessories such as the Document Viewer, re-implemented in natively-compiled Rust in place of GNOME Shell's Javascript. There are obvious differences: there are title bars, with window controls, and windows have menu bars. However, the color schemes blend title bars invisibly into the windows, and the menu bars don't work with keyboard controls. It has its own Settings app, which leads the user through a few sections rather than displaying one big list. There are no desktop icons, and no right-click menu on the desktop, either.

There are a handful of GNOME accessories here. The alpha of COSMIC keeps the document and image viewers, the system monitor, the File Roller archiver and some other tools. However, alongside its own panel, dock and settings app, COSMIC also provides its own terminal emulator, file manager, text editor, screenshot tool, and app store. To us they felt a little skeletal, but it is only an alpha version. We really did miss keyboard controls: like far too many modern GUIs, this one has its own ground-up keyboard control system, because its creators didn't know about the industry-standard one.

It was mostly stable in testing. There are a few blank panes in the Settings app, such as "Region & Language", which lead to an empty page. Some don't work: if we clicked on the button to choose the color of "Application and window background", the settings app instantly crashed. For an alpha version, we'd say it's pretty good. Kudos to the team for publishing packages for most leading distros: you can install COSMIC Epoch One on Arch, Fedora, Gentoo, openSUSE and so on.

We have read some excessively hyperbolic reviews of this preliminary release. It's not amazing or transformative and it doesn't redefine the Linux desktop. It's slightly lighter than GNOME, but not lightweight: the alpha takes nearly 7GB of disk and 1.4GB of RAM at idle. It's fast, though, and the VM booted impressively rapidly, in just a few seconds. It has more customization options than GNOME itself, which is good, as GNOME extensions will never work here. Even so, they're still quite limited, and some, like the rounded corners of the dock, align poorly and looked amateurish to our unfussy eyes. We suspect those very sensitive to graphic design won't approve.

Being all-new, it only supports Wayland: there's no X.org session, although X11 apps will work. We suspect this also means that it's as inaccessible as any other Wayland environment, and will remain that way for a long time.

If you don't like GNOME, you won't like this. We don't think COSMIC will sway fans of KDE or Cinnamon, let alone any of the really lightweight desktops. It might win over some users of pure tiling environments, though, and it brings GNOME itself some direct competition on its home turf. It's a very promising start, but thus far, it is only a start.

https://www.theregister.com//2024/09/12/pop_os_2404_cosmic_desktop/