RISCOS Versions

Details of each version of RISC OS since 1990


There are many different versions of RISC OS, which isn't surprising as it's been in development longer than any other operating system designed for ARM chips. Each new version of RISC OS added more features but kept the same simple 'drag and drop' formula.

Each of the links below will take you to a section of RISCOS.com that's dedicated to each particular version of RISC OS. Each section includes:

  • A potted history of that version of RISC OS.
  • List of compatible hardware (and emulation systems) that can support each RISC OS version.
  • Links to User Guides, Programmer's manuals etc.
  • Details on RISCOS.com products which include that version of RISC OS.

These days ARM chips can be found everywhere and there are many different operating systems which can be run on ARM hardware, but, RISC OS was the first, and for many the finest.

RISC OS 3.10 & 3.11
RISC OS 3.10 was released in 1992. It's suitable for the A305, A310, A410, A420 A440, A540, R260, A3010, A3020, A4000 & A5000 computers. It supported up to 16MB of RAM, ARM2, ARM250 and ARM 3 processors and 480K of screen memory using up to 256 colours.

RISC OS 3.50
RISC OS 3.5 was released in 1994 and was only available with the original Acorn RiscPC 600. Unlike later versions of RISC OS the ROMS were only 2MB in size as a lot of ROM components were installed on the computers hard disc. RISC OS 3.50 had a number of problems, hence the quick release of RISC OS 3.6. If you are using a machine running RISC OS 3.5 we strongly recommend you upgrade.

RISC OS 3.60
RISC OS 3.6 was released in 1995 and replaced RISC OS 3.5 in new RiscPC computers. RISC OS 3.6 contained many bug fixes and at 4MB was twice the size of RISC OS 3.5. It supported both the ARM 600 and ARM 710 processors as well as the new ARM7500 which formed the basis of the Acorn A7000/7000+ computers. It supported 2Mb of VRAM when running on RiscPC hardware and up to 16 million colours.

RISC OS 3.70
RISC OS 3.7 was released in 1996 and was the final official RISC OS release made by Acorn Computers Ltd. RISC OS 3.7 is very similar to RISC OS 3.6, but includes support for the DEC StrongARM processor. It was supplied with new StrongARM RiscPCs and was available as an upgrade pack which included the new OS chips, an upgrade CD and a new StrongARM processor card.

RISC OS 4.02/4.03/4.04
RISC OS 4 was the first release of RISC OS made by RISCOS Ltd. It was based on RISC OS 3.8, which had been intended for the Acorn Phoebe computer. It contained many bug fixes and improvements, for example it was the first version of RISC OS to natively support long file names and more than 77 files in a directory. It was available directly from RISCOS Ltd as an upgrade pack containing a new set of ROMS and a CD. RISC OS 4.02 is supplied with various VirtualAcorn products. RISC OS 4.03 was fitted to Acorn 'compatible' machines made by RiscStation, MicroDigital and Castle. RISC OS 4.04 was only supplied with Castle 'Kinetic' processor cards or 'Kinetic' RiscPCs

RISC OS Adjust 4.39 (Select 3i4)
RISC OS 4.39 is available in 2 different versions. Firstly as a set of replacement 4MB ROM chips and upgrade CD, this is known as an 'Adjust ROM'. It was also available as part of the RISC OS Select subscription service as release 3i4 (the fourth release in the third year). The 'Select' version of RISC OS 4.39 has a 'ROM image' size of 6MB, the Adjust ROM is 4MB in size. Both have similar features and both run from a 6MB block of RAM, the 4MB ROM version getting expanded into RAM when the computer first boots. RISC OS 4.39 is suitable for A7000, A7000+, RiscPC and Kinetic RiscPC computers. It's also supplied with VirtualAcorn VirtualRPC-Adjust and VirtualRPC-AdjustSA.

RISC OS Six consists of a number of sub versions, from 6.01 to 6.20. They are only available as 'softload' installs and have never been fitted into physical ROMs. RISC OS SIX includes a lot of improvements over RISC OS 4.39 and is the first version of RISC OS for some years to be fully documented with both a User Guide and a Programmers Reference Manual being available. Initially RISC OS SIX releases were only available as part of the Select Subscription scheme. Once the Select scheme closed users could buy a stand alone RISC OS Six installer disc, which was updated as later version of RISC OS Six were released. RISC OS SIX is suitable for RiscPC, Kinetic RiscPC, A7000, A7000+ and VirtualAcorn products.

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