RPCEmu Extended is an emulator for the Acorn Risc PC and A7000. It runs RISC OS on your own computer, at the speed of real hardware.
Download 1.1.16 See what it does
Free software under the GPL v2, for Linux, Windows and macOS. It runs RISC OS 3.5 and later, and works best with RISC OS 5, which is the version still being developed and is open source. No operating system is included, and the emulator will fetch one for you.
Get it
Every release is published on GitHub. This list is read from the latest one, so it cannot fall out of step with what is actually available.
| Format | For | Size | File |
|---|---|---|---|
| Linux | |||
| Debian and Ubuntu package | amd64 | 1.9 MB | rpcemu_1.1.16_amd64.deb |
| Debian and Ubuntu package | arm64 | 1.8 MB | rpcemu_1.1.16_arm64.deb |
| Archive | amd64 | 1.7 MB | rpcemu_1.1.16_linux_amd64.tar.gz |
| Archive | arm64 | 1.6 MB | rpcemu_1.1.16_linux_arm64.tar.gz |
| Windows | |||
| Zip archive | amd64 | 20 MB | rpcemu_1.1.16_windows_amd64.zip |
| macOS | |||
| Disk image | Universal | 26 MB | rpcemu_1.1.16_macos_universal.dmg |
| Archive | Universal | 23 MB | rpcemu_1.1.16_macos_universal.tar.gz |
| Also in this release | |||
| Interface documentation | Any | 150 KB | rpcemu-interface-docs-1.1.16.zip |
RISC OS itself is not in these downloads. The emulator will fetch RISC OS 5 and a ready-made hard disc from RISC OS Open when you create your first machine, and will show you their licence terms first. If you have your own ROM image, from RISC OS 3.5 onwards, you can use that instead.
What you can run
This is a fork of RPCEmu, so it does everything the original does. What follows is what it adds.
The machine
You get a Risc PC with a Kinetic StrongARM card and 512MB of memory, which is more than Acorn ever shipped. Guest code is recompiled as it runs, so the desktop feels like hardware rather than like an emulator.
How the processor card is emulated →
Games
Many Acorn games need ADFFS, and ADFFS needs the processor to fault when a program writes to protected memory. RPCEmu never did that, which is why ADFFS told people to avoid it from 2013 onwards. It faults correctly here, so those games run.
What was wrong, and how it was fixed →
Applications
The package manager installs software straight onto a machine's disc from the same repositories a real RISC OS machine uses. Over 350 applications, games, fonts and libraries, and it records what it installed so things uninstall cleanly.
About the package manager →
Sharing files
RISC OS machines shared their discs using Acorn Access and ShareFS, and that works here. Two machines on the same computer find each other with nothing to set up. Getting further than that takes one of two routes.
To real hardware
A machine sits behind NAT, which normally swallows the broadcasts Access depends on. The emulator relays them onto your real network instead, so a Risc PC in the same room joins in. One emulator per computer does the relaying and the others step aside on their own.
How machines are addressed →To other emulators
Point several emulators at one JSON server and they are all on the same network, wherever they are running. The server can sit on a Linux box while Windows and macOS machines join it over the internet. RISC OS Pyromaniac speaks the same protocol, which is Charles Ferguson's.
Setting up a shared network →When it goes wrong
An emulated machine has no network card for Wireshark to point at, so the emulator provides the capture itself. It labels Freeway and ShareFS by name, where a general-purpose tool shows only unnamed UDP traffic.
Capturing network traffic →Every machine gets its own address, worked out from its own hardware address, so two people who have never met can still put their machines on one network without agreeing anything first.
Developing
You do not have to work inside the emulated machine to build software for it. Keep your usual editor, and send the build to the guest from your own shell. The output comes back to you, along with whether it worked.
Hardware
Cards and ports a Risc PC could have taken, and one or two it could not. Each belongs to a single machine, so your other machines are unaffected.
A real Risc PC runs out of video memory at 800 by 600 in full colour. Fit the emulated graphics card and you can go to 2560 by 1440 instead. It is off until you turn it on, and RISC OS carries on using the built-in video until then.
Graphics card →Plug a device into your computer and hand it to the machine, and RISC OS sees the real thing. Memory sticks mount and can be read and written, including FAT and exFAT discs, so a file saved in RISC OS is still there on a PC. Tested on Linux; not yet tested on Windows or macOS.
USB support →The Risc PC had a slot for a second processor and almost nothing was ever made for it. There is a card here offering a choice of seven, from a 6502 to a RISC-V core, each with its own memory. Nothing exists to run on it, which is rather the point.
Second processor card →The emulator ships without an operating system, so a fresh installation has nothing to run. When you create your first machine it offers to fetch RISC OS 5 and a ready-made hard disc from RISC OS Open, and shows you their licence terms first. It will not overwrite a disc you already have.
Getting RISC OS →Set up several machines and pick one at startup. Each has its own disc, settings and configuration, so one can be a RISC OS 3.7 machine and the next a RISC OS 5 one. Save a running machine to disc and carry on later exactly where you stopped.
Several machines →Every machine can offer itself over VNC, with its own port and password, so several can run at once. It will also run with no window at all, which suits a server: nothing graphical is started, and you connect when you want to look.
Remote and headless use →Some of what RISC OS draws pixel by pixel is handed to your own computer to do in one go, with an identical result. Only operations that can be reproduced exactly are taken. On by default, and per machine.
Drawing acceleration →Fit emulated podules: a ROM card, MIDI through your own MIDI hardware, or the Computer Concepts Lark sampler. The serial port can reach a real port or dial a telnet BBS, and the parallel port can reach a real printer or write a PDF.
Cards and ports →Complete emulation of the FPA10, the floating point unit a Risc PC could be fitted with, timed to the cycle. Software that expects one finds one, and the debugger understands its instructions.
Floating point →Getting started
Take the package or archive for your platform below. On Debian and Ubuntu the .deb sorts out what it needs; elsewhere unpack the archive and run it from wherever you put it.
The first time you create a machine it offers to download RISC OS 5 and a ready-made hard disc from RISC OS Open. If you would rather use your own ROM image, from RISC OS 3.5 onwards, point the machine at it instead.
Choose the machine and it boots to the RISC OS desktop. Screen size, networking, USB and expansion cards all belong to that machine, so changing them leaves your other machines alone.
If you are here to write RISC OS software, turn on guest commands and compile from your own shell, or attach the debugger. The documentation covers both.
Building from source, or on a platform without a published build? The compilation guide covers Linux, Windows and macOS, and the README is the fullest reference for everything on this page.
News
Taken from the repository, and refreshed through the day.
RPCEmu