Got an old Raspberry Pi spare? Try RISC OS. It is, something else
The new version of RISC OS, the original native Arm OS, runs on eight or nine Arm-based platforms, including the Raspberry Pi Zero, 1, 2, 3 and 4 – and on that last two, this release supports wireless networking.
RISC OS 5.30 comes with quite an assortment of applications, and plenty more are online (click to enlarge)
RISC OS 5.30 is the latest release of Acorn's original native operating system for its Arm processors. Original, but not first: As Acornsoft project lead Paul Fellows told the Reg in 2022, what was then called "Arthur" supplanted a far more ambitious project called ARX, which never shipped. ROS 5.30 is the first stable release from the RISC OS Open (aka ROOL) project since version 5.28 in 2020. (If you have that, you can upgrade in place.)
RISC OS Open project leader Steve Revill, who we interviewed last year, told us:
Acorn's original, and very comprehensive, documentation has been updated for this release, too:
It also includes a very basic web browser, but one without Javascript – so it's limited (click to enlarge)
New owners RISC OS Developments made RISC OS 5 open source in 2018 and it's still in active development under RISC OS Open. That is no trivial project: Although by modern standards this desktop operating system is tiny, significant chunks of it were hand-coded in Arm assembly code – for 20th century hardware. Version 5.30 supports seven platforms: Post-1994 Acorn machines with the IOMD chipset, the Iyonix and Beagleboard hardware we described in 2010, and Elesar's Titanium PC, plus three Arm development boards (the IGEPv5, the OMAP 5432, and the Pandaboard). And, of course, the Raspberry Pi, which is by some distance the cheapest member of the family. For now, RISC OS does not support the Raspberry Pi 5, but it does run on the Pi Zero, 1, 2, 3 and 4, and it's fast and responsive on all of them.
We found the new support for the Wi-Fi controllers in the Raspberry Pi 3 and 4 a little clunky – for instance, changes to the network configuration require a reboot. Even so, it's a lot better than nothing. First, you enable the SDIO WLAN interface; then, after a restart, a new Wi-Fi icon appears on the left of the icon bar, which allows you to connect to both 2.4 and 5GHz networks.
This is a fairly modernized and refurbished late-1980s single-user GUI-based OS, and that implies some limitations. It was first released the same year as OS/2 1.0, long before Apple System 7 or Windows 3.0. In fact, it'll remind you of Windows 3 on MS-DOS: it's a single-tasking text-mode OS, with networking, on top of which is a graphical desktop that does cooperative multitasking. RISC OS gives applications access to much of the memory map, and so if a program accidentally scribbles over the wrong parts of that address space, the whole computer can freeze up – which in testing our Pi 400 did several times.
But saying that, it's an admirably complete OS, in this vulture's opinion, with quite a rich portfolio of applications. RISC OS 5.30 comes with a selection of productivity apps, plus development tools, including a choice of editors, Python, Lua, and a C compiler – and of course with a 32-bit version of BBC BASIC V, a fully structured interpreter which also supports inline Arm assembly language.
This is, in a way, a mature OS with an ecosystem and an aftermarket. (Which, we feel we must explicitly spell out, means that quite a few of those third-party applications and drivers will cost you money.) There are emulators that will let you run 20th century Acorn apps that you can find online, but this isn't an emulated vintage environment like Amiga Forever. It's not meant for running games from thirty years ago. This is a native bare-metal OS, built on 1980s roots but updated for 21st century hardware. It's also not an experimental project with little practical use, like Redox OS or Serenity OS, interesting though those are.
The RISC OS GUI – called simply the WIMP – will take some getting used to. It has no application menu bars at all, for example. You middle click on things to get at the relevant menu; this GUI only has context menus, nothing else. (What menu is easier to hit than whacking the mouse pointer up to the top of the screen? One where you don't move the mouse at all! The menu is always where your mouse already is.) And yes, there is an icon bar along the bottom where you can bring up menus and windows for running programs and other things; but when you want to do something in an app, you click the menu mouse button in the context of that application rather than look for a menu bar.
The idea of having a directory navigation right in the save dialog, so you can choose where to put the file, was a hack invented for the original 128kB Macintosh, because it didn't have enough RAM to show a filer window alongside your app. RISC OS didn't need that: In 1987, it ran on a 32-bit RISC workstation with a meg of RAM, so its Save dialog just has an icon that you drag to the directory window you want.
Similarly, this is the OS whose original GUI some like to think may have inspired NeXTstep's Dock, which in turn inspired the Windows 95 taskbar. RISC OS doesn't work like them, because it's often thought they got their ideas from RISC OS.
When you run a RISC OS application, all that happens is that it puts an icon in the icon bar. Middle-click that new icon for global options, or in most apps, just left-click it to open a new empty window. The right button doesn't go unused: it's called Adjust and it modifies what a left-click would do. So, for example, left-click a scrollbar to move in that direction, but right-click it to move the other direction. Left-click an "OK" button to save your settings, but right-click it to Apply them without closing. It's odd, but in its way, it's more elegant than any other mouse-driven desktop.
As you can no doubt tell, the Reg FOSS desk is very fond of RISC OS. It was the first GUI we got to know, on our Archimedes A310 – back when Apple's System 6 was new. That ran best on the Mac IIci, which was $6,269 – in 2024, that's $15¾K or £12½K. When this vulture was 20, our used Archie cost £800 (one kilobuck).
RISC OS is a fascinating glimpse into another world. It has almost no influence from the worlds of 32-bit Windows, or MacOS 7 or Mac OS X, or Linux – because they hadn't been invented yet. It has a superbly elegant graphical desktop, but it's almost totally unlike anything else you've ever seen.
Imagine if the classic 1980s Motorola 68000 computers – the Atari ST, the Amigas, or the Classic MacOS pre-PowerPC Macs – and their CPUs had kept on developing and evolving into the present day, completely separately from modern world of 64-bit chips and both FOSS and proprietary OSes. That's what RISC OS is: A time-traveler from the 1980s, alive and well, modernized and updated, but almost completely free of any influence from the rest of the 32-bit World Wide Web era. You will find it very disorienting, especially if all you know is post-1990s OSes, but that's part of the fun. Almost everything you could want – web browsers, email, office-type apps, games, dev tools – it's all there, and enough to get you started is here, free and open source.
The 2024 release of RISC OS runs fine on a £12 ($15) Raspberry Pi Zero – and the same SD card will boot any model up to the Pi 4 or 400. (But not, for now, the new, 64-bit-only Pi 5.) If you don't have one of those, but have an old Pi 1, 2 or 3 lying in a drawer somewhere, dusty and neglected, dig it out and put RISC OS onto an SD card – even a 2GB card will do – and give it a try. ®
Bootnote
ROOL is not the only flavor of RISC OS, and the machines listed above aren't the only modern RISC OS hardware in the world – they just happen to be the ones that the RISC OS Open project currently supports. There are some other devices that aren't included in version 5.30 right now, because there are too many outstanding bugs. Some of these have their own separate ports of RISC OS available. This includes the PineBook and PineBook Pro laptops, and the PINE A64 board.
In addition, there are two other noteworthy editions.
There's a distribution specifically aimed at the Raspberry Pi, called RISC OS Direct, also from RISC OS Developments. We talked to Andrew Rawnsley of RISC OS Developments, who told us:
There's also a separately-maintained 26-bit branch of RISC OS for original Acorn hardware, although these days most users run it on x86 PCs or Macs on a commercial emulator called Virtual Acorn.