RPCEmu Linux Guide


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         ether 00:00:00:00:00:00  
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Next try to ping (the emulator gateway) and your host system IP. If that works fine you only have to configure the host system to enable packet forwarding. If you're running a ''firewall'' package on your host system then it's recommended to use it to configure port forwarding. You can also enable forwarding by using these commands on the host system:
Next try to ping (the emulator gateway) and your host system IP. If that works fine you only have to configure the host system to enable packet forwarding. If you're running a ''firewall'' package on your host system then it's recommended to use it to configure port forwarding. You can also enable forwarding by using these commands on the host system (you'll need to re-run these every time you boot your machine):
  sudo iptables -I FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
  sudo iptables -I FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT

Revision as of 12:20, 22 November 2008



This quick guide describes how to download/install/configure RPCEmu for your Linux environment. The guide is written for a Debian Linux distribution like Ubuntu, Knoppix and Xandros. This doesn't mean it won't work on other Linux distributions but commands, package names and places of files could be different from those described in this guide.

Notably for RPM-based distributions like Fedora or SUSE the apt-get command won't work to install packages... try using yumex to search for similarly-named packages to install. If you have success then please list the package names you used below.

Other Unix-like platforms such as FreeBSD or Mac OS X may work - feel free to add details of your experiences here or post to the RPCEmu mailing list. There is also a Windows version of RPCEmu which you may be able to build from source - just try the SVN sources or ask the list for more details.

If you have any problems, see the Troubleshooting section or known RPCEmu issues.


What do you need:

  • Linux system: for best results P4 or similar processor at about 2GHz or more.
  • A working X Window system (X11)
  • Internet connection
  • Harddisc space: 62 MB for the emulator and 500 MB for RISC OS applications
  • Image files of RISC OS ROMs 3.6, 3.7, 4.02 or 4.39 (best is RISC OS 4.02)


Open a terminal window. Get the required packages for the RPCEmu emulator by using apt-get:

sudo apt-get update
sudo apt-get install build-essential subversion liballegro4.2 liballegro4.2-dev liballegro4.2-plugin-jack unzip wget

Get the lates RPCEmu package with subversion. If you have a firewall for outgoing traffic you may need to open TCP and UDP port 3690 to allow this.

svn co svn://svn.riscos.info/rpcemu/trunk rpcemu

After downloading:

cd rpcemu/src/

If you get an error that the system doesn't recognize any of the above commands then install the next packages:

sudo apt-get install make automake autoconf

You can get some warnings from the allegro library, just ignore them.

Now you have two options. Create the interpreter version of rpcemu or the dynamic recompiler. The first one is slower but more stable and it's possible to select an ARM processor. The recompiler version has the advantage to be five times faster but only runs the StrongARM (SA) processor. If you want to run the SA processor under RISC OS 4 then I recommend the recompiler because of a current problem in the interpreter with bad screen redraws and abort on data transfers in 16 bits per pixel modes. The dynamic recompiler only works on x86 host processors.

To select the interpreter:


To select dynamic recompiler:

./configure --enable-dynarec

some output of the configure command
Some output of the configure command

If you see the output and get no errors then compile:


If there were no errors then the emulator is ready for use. Go back to the rpcemu directory:

cd ..

To get the emulator running you only need the RISC OS roms. I recommend to get RISC OS 4.02 because it has more support for internet (RISC OS 4.39 hasn't been as well tested). As RISC OS is copyrighted, you have to get them yourself from a real RiscPC. Just open a taskwindow (press CTRL+F12) on your RiscPC and enter the next commands:

*save rom1 03800000 03900000
*save rom2 03900000 03A00000
*save rom3 03A00000 03B00000
*save rom4 03B00000 03C00000

Get the 4 files (rom1 rom2 rom3 rom4) to your linux host system and copy them to the roms directory. If you have the wget package then download the bootimage:

wget http://b-em.bbcmicro.com/arculator/hdboot.zip

Otherwise download the archive from the site with your browser - try right clicking and using 'Save link as...' to choose where it puts the download. Extract the archive to the rpcemu directory and overwrite cmos.ram and hd4.hdf with those inside the archive using:

unzip hdboot.zip

Create two directories in the rpcemu dir:

mkdir hostfs
mkdir poduleroms

Edit rpc.cfg in the rpcemu dir:

mouse_following = 1
cdrom_type = 0
cdrom_enabled = 1
blit_optimisation = 0
refresh_rate = 60
stretch_mode = 0
sound_enabled = 1
vram_size = 2
cpu_type = ARM710
mem_size = 32
ipaddress =

(you should be able to double click a .cfg file to edit it, or type nano rpc.cfg for a simple editor)

Start up the emulator in your X11 environment:


A window will pop up and the emulator loads the OS and runs the Boot system. You've got a working RISC OS desktop on your linux system.

Booting from HostFS

Run the emulator and wait till the system has been booted. Now open the Filer window of your HostFS disc. This disc is linked to your previously created hostfs directory. It's now empty but you can use this disc to transfer files from the host system to RISC OS and back. The ADFS harddisc where the system boots from is linked to an image file hd4.hdf on your host system.

Open !Boot (shift doubleclick) on the bootdisc and go to directory Choices.Boot.Task.!hostfs. Edit !Run (shift double click) and change line:

rmensure hostfs 0 rmload <hostfs$dir>.hostfsrm


rmensure ArcEmHostfs 0 RMLoad <hostfs$Dir>.hostfsrm

Copy !Boot from IDEDisc4 to the HostFS disc.

Now press F12 and enter the command:

*configure filesystem HostFS

Editing !Run from !hostfs application
An example of how your desktop looks like when you're at this step

Return to the desktop. Go back to the linux console and copy the HostFS module in the !Boot to your dir poduleroms:

cp hostfs/\!Boot/Choices/Boot/Tasks/\!hostfs/hostfsrm,ffa podulesroms/

Shutdown RISC OS and quit the emulator.

Enlarging emulated ADFS drive

So far we've set the emulator to boot from HostFS. So you can put !Boot and all your files on HostFS and have them accessible from RISC OS and Linux. A few applications may not like this, so you can also create an emulated ADFS hard drive as follows:-

Get HForm from the Arculator website and unzip it:

wget http://b-em.bbcmicro.com/arculator/rpchform.zip
unzip rpchform.zip

It's a floppy disc image which unpacks to hform.adf - we'll now make this appear as an ADFS floppy drive.

Boot the emulator and press CTRL+END. A menu pops up at the left top. Select 'Disc' -> 'Load drive :0...'. Select hform.adf and press 'OK'. Open drive 0 (click on the :0 icon at the iconbar) and run !HForm. Format the ADFS bootdisc with these options:

Drive: 4
Retain shape: No
Drive type: OTHER
Sectors per track: 63
Heads: 16
Cylinders: 1024
Drive parameter init flag: 1
Parking cylinder: 1023
No more changes to defect list
Initialise the drive
Soak test: None
Bootable disc: Yes
Longfilenames: Yes (only available for RISC OS 4)
Confirm format: Yes
Large file allocation unit (LFAU): 2048

You have created a large harddisc image of 504MB for ADFS drive 4. If you want a bigger image then enlarge number of cylinders. Note that the parking cylinder must be the total amount of cylinders minus 1 (it isn't used for the formatting, but other values may confuse HForm). Note also that you have to multiply the suggested LFAU value by 2. So if HForm suggests 1024 then change it to 2048.

Output from application HForm
HForm in action on ADFS drive 4

Installing RISC OS 4 Boot system

Go to directory hostfs and download the RISC OS 4 Boot installer archive from the riscos.com site:

wget http://support.riscos.com/Support/Releases/RO4install.zip
mv RO4install.zip RO4install,ddc

As you probably don't have a dearchiver for RISC OS get SparkPlug:

wget http://www.davidpilling.net/splug.bas
mv splug.bas splug,ffb

Open your HostFS disc in RISC OS and run the basic file splug. After !SparkPlug has been created, doubleclick on the archive file RO4install and extract !RO4Install to your Harddisc4 disc. This can take some minutes (look at the SparkPlug icon to see if the extracting has finished).

Now you can install the RISC OS 4 boot sequence to either the emulated ADFS drive or HostFS. The following instructions are for ADFS:

Doubleclick on the RISC OS 4 installer, drag the !Boot icon to the filer window of Harddisc4, click on 'Continue' and in the next dialogue click on 'Start install'. Click on 'Continue' in the warning window and click on 'Continue' in the next dialogue. Wait till the installer is finished and click 'Continue' again. In the next dialogue click 'Continue' to install Apps and Utilities. After installation click 'Exit'

The complete RISC OS 4 Boot install process

Press F12 and enter the commands:

*configure filesystem ADFS
*configure drive 4

Return to the desktop. Open the installed !Boot dir and go to directory Choices.Boot.Task. Open your old !Boot directory on the HostFS disc and copy !hostfs from Choices.Boot.Task to the same directory inside the new installed Boot (see images below).

Copy !hostfs from this dir: Image:RPCEmu-copyhostfs-source.png to: Image:RPCEmu-copyhostfs-dest.png

To install on HostFS the install is the same, only drag the !Boot to the HostFS filer window, you don't need the *Configure commands, and you shouldn't need to copy across !HostFS.

Shutdown RISC OS and click 'Restart' to boot the OS with the new Boot. You now have a fully working Boot with the standard RISC OS 4 apps and utilities.

CD-ROM support

Check if the symbolic link /dev/cdrom points to your CD-ROM device at the host system. You can check this by trying to mount this device to a directory. Insert a data CD-ROM in your drive and enter the commands:

mkdir ~/cdrom
sudo mount /dev/cdrom ~/cdrom
ls ~/cdrom

If you don't get any errors and see the contents of the disc then the link works. If not, your distro may have automatically mounted it somewhere else. Try this:


If you have a line in the output that looks something like:

/dev/dvd on /media/cdrom type iso9660 (ro)

then your CD-ROM is called /dev/dvd (or it may be called /dev/scdX where X is a number). Make a symbolic link of this to /dev/cdrom:

sudo ln -s /dev/dvd /dev/cdrom

and try the above three commands again.

Now unmount the disc and remove dir cdrom:

sudo umount ~/cdrom
rmdir ~/cdrom

Edit rpc.cfg and check if:

cdrom_enabled = 1

Start the emulator and open the RPCEmu menu. Select 'Settings' -> 'CD-ROM' -> 'IOCTL'.

RPCEmu menu for CD-ROM emulation

Double click the !Boot icon on the RISC OS bootdisc. Select 'Discs' in the configuration dialogue, configure one CD-ROM drive and click on 'Set'.

Main RISC OS 4 Boot configuration dialogue
Main Boot Configuration dialogue
RISC OS 4 Disc configuration dialogue
Disc configuration dialogue

Click 'OK' in the next warning dialogue. Open the CD-ROM by clicking the CD-ROM icon :0 at the left of the iconbar.

It's also possible to mount ISO images instead of real CD-ROM's with RPCEmu. Open the RPCEmu menu and select 'Settings' -> 'CD-ROM' -> 'ISO image...', select an ISO image to mount and click 'OK'. Open the CD-ROM image by clicking the CD-ROM icon :0 at the left of the iconbar.

Note every time you start RPCEmu, you have to select 'IOCTL' or 'ISO image...' to enable CD-ROM support.

Network support

RPCEmu uses a TAP tunnel device to send packets between the emulator and the host system. Unfortunately these devices can only created by root, therefore RPCEmu must be run as root. So to enable it you have two options:

1. Use sudo to start RPCEmu:

sudo ./rpcemu

RPCEmu will automatically drop root privileges as the tunnel has been created. This has a disadvantage that you have to enter a password to get RPCEmu going.

2. Make root the owner of the rpcemu binary and set the user s-bit. Enter the two commands:

sudo chown root rpcemu
sudo chmod u+s rpcemu

And edit rpc.cfg to add this line:

username = <your standard username>

In this case RPCEmu will also drop root privileges after the tunnel has been created.

Check rpc.cfg for the IP address. It should be:

ipaddress =

Run RPCEmu with root privileges. You should not get messages like:

Error setting TAP on tunnel device: Operation not permitted
Networking unavailable

Check if the emulator has created a tap interface and that it's IP address has been set to

ifconfig -a

You should get something like this:

tap0      Link encap:Ethernet  HWaddr 00:ff...........
          inet addr:  Bcast:  Mask:

Next try to ping the interface:


You should get something like this:

PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=64 time=0.079 ms
64 bytes from icmp_seq=2 ttl=64 time=0.069 ms

Get the latest !System from Castle:

cd hostfs
wget http://www.iyonix.com/32bit/download/System.zip
mv System.zip System,ddc

Copy the EtherRPCEM directory from riscos-progs to the hostfs dir:

cp -r riscos-progs/EtherRPCEm/ hostfs/

In RISC OS open the HostFS disc and extract archive System. Doubleclick on !SysMerge. Open dir EtherRPCEm and copy !Boot from the EtherRPCEm dir on the !Boot of your bootdisc. Run !Boot and click 'System' to open the System merge dialogue. Drag !System from the EtherRPCEm dir to it and click 'Merge'.

Main RISC OS 4 Boot Configuration dialogue
Main Boot Configuration dialogue
System Merge dialogue
System Merge dialogue

Click 'Network' in the configuration dialogue and click 'Internet' in the next dialogue. Enable 'TCP/IP Protocol suite' and click on 'Interfaces'.

Network configuration dialogue
Internet configuration dialogue
Interfaces dialogue

Enable 'RPCEmu' interface and click 'Configure...'. Set these settings:

Obtain IP address: Manually
IP address:

Click 'Set' and 'Close' in Interfaces dialogue. Open the Routing dialogue and set these settings:


Click 'Set' and open the Host Names dialogue. Set these settings:

Host name: rpcemu
Local domain: riscoslocalnet.invalid
Primary name server: use 1st IP address from output command cat /etc/resolv.conf
Secondary name server: use 2nd IP address from output command cat /etc/resolv.conf
Tertiary name server: empty or 3rd IP address from output command cat /etc/resolv.conf
Name resolver module: Resolver Acorn
Enable Use name server also

Click 'Set' and 'Close' in the Internet configuration dialogue. Next Click 'Set' in the Network configuration dialogue and click 'Reset now' in the next question dialogue.

After the emulator has booted open a taskwindow (CTRL+F12) and enter:

*ifconfig -a

You should get something like this:

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet netmask 0xff000000 
        inet netmask 0xffff0000 broadcast
        ether 00:00:00:00:00:00 

Next try to ping (the emulator gateway) and your host system IP. If that works fine you only have to configure the host system to enable packet forwarding. If you're running a firewall package on your host system then it's recommended to use it to configure port forwarding. You can also enable forwarding by using these commands on the host system (you'll need to re-run these every time you boot your machine):

sudo iptables -I FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
sudo iptables -t nat -A POSTROUTING --source -o eth0 -j MASQUERADE
echo "1" | sudo tee /proc/sys/net/ipv4/ip_forward
echo "1" | sudo tee /proc/sys/net/ipv4/ip_dynaddr

This will forward packets out to the eth0 interface. You'll need to replace eth0 with your outgoing internet connection. To find this on the host system, do:

route -n

The output might be something like this:

Kernel IP routeing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface   U     0      0        0 eth1     U     1000   0        0 eth1         UG    0      0        0 eth1

Find the line with Destination set to this is your default route. Here the Iface is eth1. So replace eth0 with eth1 in the iptables command above. If you change network environment, maybe from wired network to Wi-Fi, you may need to recheck this value.

Try to ping some hosts on the internet from the emulator like google.com, riscos.com etc. If that works you are connected to the internet with RPCEmu.

If you want to allow access to servers running on the emulator from the Linux machine or other machines on the network you'll need to add additional forwarding rules. Consult a guide on iptables for how to do this.

Note that for the moment ShareFS won't work since it'll need some more iptables rules to forward UDP broadcasts (ports 32770/32771/49152/49171) from the host.

Installing NetSurf

Go to the hostfs dir and download the latest NetSurf from http://www.netsurf-browser.org or use wget:

wget http://www.netsurf-browser.org/downloads/development/netsurf.zip

Rename netsurf.zip to netsurf,ddc. Start the emulator and create a dir Internet on your bootdisc. Extract the contents from the netsurf archive to this dir. Use the Boot Merge (click 'Boot' and then 'Install' see below) and and the System Merge facility to merge !Boot and !System from the Internet dir to your boot system. Next reboot the emulator and start !NetSurf from dir Internet. Enter a valid url in the top bar and you're on the world wide web.

Main RISC OS 4 Boot configuration dialogue
Main Boot Configuration dialogue
RISC OS 4 Boot sequence dialogue
Boot sequence dialogue
RISC OS 4 Boot Merge dialogue
Boot Merge dialogue


RISC OS won't boot properly, or behaves oddly

As on a real RISC OS machine, it uses the CMOS RAM to hold important system settings. In the emulator these are stored in the cmos.ram file. If you use the emulator for the first time, or change the version of RISC OS you're running, you need to reset the CMOS. To do this, start the emulator while holding down the Delete key. Just as it would on a real machine, it resets the CMOS to factory settings for the version of RISC OS you happen to be running.

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