ROOL Calls for Aid As It Seeks to Modernize Acorn's RISC OS for the Era of the 64-Bit Raspberry Pi

RISC OS Open Limited (ROOL) has announced a "moonshot" program with which it aims to bring the eponymous operating system bang up-to-date — starting with a port compatible with 64-bit-only Arm processors and the Raspberry Pi 5.

"As the 40th anniversary of the first Arm chip approaches, RISC OS is facing an existential challenge: much of its core is written in hand-crafted 32-bit assembly language which relies on 32-bit processor modes. Now that all new Arm architectures, such as the one used on the Raspberry Pi 5, are 64-bit only designs this niche OS is at risk of becoming obsolete," admits ROOL managing director Steve Revill, who was previously an engineer at RISC OS creator Acorn. "To ensure RISC OS remains viable, we must undertake a significant program of modernization. Our team at ROOL has estimated that this will require a dedicated group of developers working full-time over several years."

RISC OS was, as the name suggests, an operating system targeting reduced instruction set computers — specifically Arm Computers' Archimedes and later RiscPC systems, which used the Arm architecture the company itself created. Acorn has long since stopped making computers, but Arm — formerly Acorn RISC Machines — lives on, and so too does RISC OS thanks to projects run by Castle Technology, later RISC OS Developments, and RISC OS Open Limited (ROOL).

While working Acorn machines are somewhat thin on the ground these days, the history of Arm provides the software with a lifeline: RISC OS is designed specifically to run on Arm chips, and in its modern incarnation has been tailored to work perfectly on the Raspberry Pi family of single-board computers — including patches to add support for classic Acorn software like Magpie and Zarch. The only problem: time and technology are marching further on, and the introduction of the Raspberry Pi 5 has brought with it incompatibility with RISC OS — an issue that ROOL warns will only get worse.

With the bulk of the operating system written for 32-bit processors — and directly in assembly, meaning that it uses machine code that can't be recompiled for 64-bit devices — RISC OS is in need of a rewrite, and ROOL is in need of resources. As a result, the company has announced a move away from its previous bounty-based approach to incentivize contributors and to a "moonshot" program targeting larger-scale contributions. For this, Revill explains, the company will need to find funding partners, software engineers interested in working on the rewrite, and community advocates "to help raise awareness and build momentum."

"We need the backing of individuals and organizations who recognize the significance of RISC OS and its place in computing history," Revill concludes. "If you or your network might be able to support this effort – whether through funding, expertise, or advocacy – I would love to explore possibilities with you."

More information on the moonshots program is available on the RISC OS Open website; those with a compatible 32-bit-capable Arm-based system, including the Raspberry Pi 4 or prior, BeagleBoard, PandaBoard, Wandboard, and PineA64, can try the operating system themselves from the site's download page.