RISC OS 3.50

Released 1994 - RiscPC class



RISC OS 3.50 is included with the following products.

Classic RISC OS ROMS for Emulators

The Classic ROMS collection brings together a fully licenced collection of ROMS for both Arthur and RISC OS. The collection covers the entire range of 32 bit ARM (Acorn Risc Machine) computers developed by Acorn Computers Ltd from the A310 to the StrongARM RiscPC. Every ROM comes with Boot Sequence, Apps, Utilities and instructions for a range of emulators...

Available for immediate download - 10.00




  • Series 1 RiscPC with Arm600 processor, hard disc drive and optionally a 1x or 2x CD reader.



The following support documents relate to this version of RISC OS:

Further support documents for RISC OS users can be found here.
Further support documents for RISC OS developers can be found here.



RISC OS 3.5 was the first version of RISC OS that shipped with the Acorn RiscPC in 1994. The RiscPC marked a notable hardware change when compared with earlier machines such as the A5000. The new VIDC20 video chip could manage 'deep' colour modes with up to 16 million colours and supported up to 2MB of VRAM as opposed to the 512KB of earlier machines. The introduction of the ARM 610 processor provided considerably more performance than the ARM 2/3 chips of the earlier machines. Acorn therefore made a number of tweaks to the RISC OS desktop such as replacing the bitmap font with a user selected anti-aliased outline font. RISC OS 3.5 was the first version of RISC OS to support more than 16MB and use standard memory modules with a single memory controller.

As was often the case with Acorn Computer products the new RiscPC hardware was ready well before the new version of RISC OS had been finished. The RiscPC architecture supported a ROM of up to 4MB size but RISC OS 3.5 only used half that size. The rest of the components that would be committed to the ROM in future versions of RISC OS were instead supplied on the hard disc and were patched in when the machine booted. As such RISC OS 3.5 is the only version of RISC OS that needs a hard disc (or image) in order to function properly.

Upon release RISC OS 3.5 and the new RiscPC machine were very warmly greeted by the RISC OS market but it wasn't long before problems started showing up. The ARM610 CPU running at 40Mhz didn't deliver the expected performance boost over some third party ARM 3 cards. In tests this author compared a new Risc PC with an expanded Acorn Archimedes 310 (fitted with a Computer Concepts ColourCard Gold, 4MB RAM and a 35Mhz ARM 3) and discovered that in many tests the RiscPC was only 10% quicker.

All versions of RISC OS from 3.5 onwards would only be suitable for the RiscPC or A7000 class machines.

Notes : the RiscPC was badged as 'Acorn RiscPC', it was only when RISC OS 3.6 and the Arm710 processor were released that machines were badged as 'Acorn RiscPC 600' or 'Acorn RiscPC 700'. The very final batches of RiscPCs made in 1998 were also badged as 'RiscPC' but were fitted with a different motherboard.








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