The easiest way to run RISC OS on the Raspberry Pi is to visit the RISC OS Open Ltd (ROOL) website and buy a RISC OS Pi SD card for £12 plus P&P. Once inserted into a Rasberry Pi, switching on will boot directly into the RISC OS desktop. From there you can run RISC OS software such as that on the NutPi starter bundle, or write your own.
This article, however, is about installing RISC OS on the Pi for free. As such it embraces the Raspberry Pi philosophy of not being afraid to get "hands-on" and being DIY minded. This tutorial uses an Apple MacBook Pro laptop to write RISC OS onto a blank SD card. Readers who would rather use MicroSoft windows may like to take a look at this YouTube video. The process is similar.
However you write RISC OS onto an SD card you will need;
• Micro USB Power Supply (Output of 5 Volts DC at up to 1 Amp)
• Class 4 SD card of 2 or 4 GB
• USB mouse & keyboard
• HDMI monitor & connecting cable
I bought the Maplin N19HX power supply for £15.99, and an (Intenso) SDHC Class 4 memory card for £3.99. Class 6 SD cards are suitable, not so class 10. I already had suitable keyboard, mouse, and monitor. I paid £1 for an HDMI cable from The Pound Shop. Power supplies rated less than 1 Amp (1000 mA) are a source of problems and some USB cables can not carry the 1 Amp required. Avoid those with obviously thin wire. MathMagical sell a power supply that will easily power the Raspberry Pi from a 12 volt car battery.
As mentioned above, I used an Apple laptop to write the SD card. Mine has a built in SD card reader but older laptop's may not in which case an adaptor is needed to connect the blank SD card up to a USB port. A suitable adaptor, more commonly used to pull photographs & video off SD cards from digital cameras, is shown in figure 1.
The SD card image of the current version of RISC OS for the Raspberry Pi is obtained by visiting the Raspberry Pi Downloads page. Scroll down to the foot of the page, to the RISC OS section as shown in figure 2. With the Safari web browser set to Open "safe" files after downloading click either Image or Torrent to download and unpack a zip file containing RISC OS.
Figure 3 shows the resulting Finder window. In Finder's View menu I've selected Show Path Bar as I need to know where the unzipped SD Card image file has been placed. Mine is in /Users/helenjones/Downloads.
We're now going to access the command line within the Mac using the Terminal app. Figure 4 shows where this can be found using Finder. It's within Utilities in the Applications folder.
Double click on the image of the monitor in the Finder window to open the Terminal window shown in figure 5.
With the blank SD card NOT plugged in, type df -h into Terminal. You should get something like figure 6.
Plug in the blank SD card to the laptop. Into Terminal again type df -h and compare your output with what was obtained previously. Mine is shown in figure 7.
The crucial line is the one that runs;
/dev/disk1s1 1.8Gi 243Mi 1.6Gi 13% 512 0 100% /Volumes/NO NAME
which was not present before and so must be the blank 2 GB SD card. We want the device name, which in my case is /dev/disk1s1 but *BE CAREFUL* yours may be different. Now unmount with the command;
diskutil unmount /dev/disk1s1
as shown in figure 8.
The tricky line comes next in which you need to accurately specify the pathname of the input file and where the output file is to be placed. For me this is;
sudo dd if=/Users/helenjones/Downloads/riscos-2013-07-10-RC11/riscos-2013-07-10-RC11.img of=/dev/disk1
as shown in figure 9.
Once you've entered your system password you may have to wait up to half an hour before Terminal reports that the file transfer is complete. Figure 10 shows what to expect.
Finally, eject the SD card with; diskutil eject /dev/disk1 as in figure 10. The job is now done. Take the card out of the adaptor, insert it into the Raspberry Pi and power up the system. After a short delay you should get the RISC OS desktop on screen.
With thanks to Helen Jones for the use of her Apple Laptop
Comments by email are welcome.
Chris Hill writes:
While sitting waiting for RISC OS to write to my SD card, I realised it would be faster if I added the parameter bs=1M to the dd command. This is on Linux (Ubuntu) but I expect it would work on a Mac too.
Chris is @Chillly on Twitter.
Readers without an Apple Laptop can install RISC OS on the Raspberry Pi using only a Raspberry Pi !
Step 1 - Boot up the standard Debian Linux from the standard Raspberry Pi SDHC card.
Step 2 - Plug in a 4 Gig USB memory stick and mount it - standard Linux mount.
Step 3 - Download the Alpha Image to the empty space on the 4Gig memory stick.
Step 4 - Plug in a USB adapter with a second SDHC card plugged into that.
Step 5 - Copy the image to the second card - sudo dd if=RISCOS_Alpha_13Jul2012.img of=/dev/sdb
Step 6 - Shutdown Linux, Change SDHC cards and Power up.
For those without a network, the image could be preloaded onto the 4Gig memory stick using any Windows PC (and quite probably, an Apple)
John also posts on the Raspberry Pi forum for RISC OS.
Matt Kevan writes:
Thanks for your guide to installing RiscOS on the Raspberry Pi. I'm really excited about playing with RiscOS again, having not used it since my trusty A410 died about 10 years ago. Just one thing; I noticed for someone fairly n00bish like me it's not immediately obvious that you need to drop the 's1' bit from the device name when running the dd command. Now I know it's important I can see it isn't in your example command, but it took me a couple of false starts and a fair amount of googling before I found out why it wasn't working. Also I discovered that as dd doesn't give any visual feedback, you can press CTRL-T to get a progress report.
Many thanks and keep up the hard work.