Torbjörn Granlund’s Excellent resource on running free OS’s on Qemu

Ever get tired of x86 on x86?  yeah me too.

How to solve that problem?

Simple, grab QEMU, and jump off into all those cool RISC processors of the 1990’s that were going to save us all from the WINTEL hegemony!

Lots of instructions, samples, images, and hints here:

It’s really more comprehensive than I’ve sat down to do, so yeah it’s awesome!

Supported platforms include:


Virtual Acorn – Fun with Virtualized RISC OS

(this is a guest post from Tenox)

Virtual Acorn let’s you run RISC OS on a Windows or Mac OS X host like VMware, VirtualBox or Qemu. The company page has this picture:


…you probably don’t want to do this for real!

Currently there is a sale going on and you can buy VirtualRPC-SA for about $100. My primary reason for getting it was of course porting aclock to RISC OS. I have also decided to purchase the original compiler because it allows to target the funky 26 bit CPU. Alternatively GCC is available.


VirtualRPC comes “pre-installed” with the OS on a ROM image. The operating system at first glance is nice looking and for a while it’s good fun in to explore and play. You can even browse the web and use weird applications like you never seen. You can find a lot of software apps here and here and here. However for any more than that it’s not very unusable.


Porting of aclock was was by far a most difficult one ever, maybe except Plan 9. To display text on the screen you need to use system calls directly, for which you use a special function called _swi() or _swix(). There is no concept of sleep() so I had to improvise with an empty loop. Fortunately there are screen codes that allow to position the cursor, clear screen etc.

void cls(void) {
     (void) _swix(OS_WriteI + 12, 0);

The result is far from pretty but it will do for version 1:



Some funnies, which actually weren’t that funny at the time:

A directory separator in RISC OS is “.” (yes a dot) for example: root.folder.subfolder.file. The C compiler expects .c as a file extension as it would on Unix or Windows. Except naming file “aclock.c” would make a directory aclock with c file in it. Fortunately, or maybe not, extensions in RISC OS are actually prefixing, not postfixing a file. So you have c.aclock or o.aclock. Except c and o are directories. You can see c and o folders in the screenshot above. Are you confused yet?

The operating system does actually have concept of a command line interface. Try to figure out the commands!

  • dir – change directory aka “cd” on the planet Earth
  • cat – list directory aka “ls” or “dir” in your normal OS


There is more, so I encourage you to try yourself just for the fun!


Microsoft Giano

I stumbled across this the other day, Giano, a simulation framework.

Included is a bunch of stuff, like a basic x86 / cepc (with Windows CE 6.0 image), an Xbox 360 emulator, a SPOT emulator, some eval boards (AT91EB63?) with both MIPS and ARM cpus that even include a doom kernel like experience! A Macintosh G5 (I wonder if it’d boot with Apple ROMS..?) Oh and..


The VAX code is taken from SIMH but I guess to show how extensible the framework is, they mashed in enough microvax to get it going.

SIMH in a way you’ve never seen it…

At any rate, here is some other screen shots of Giano in action….


The Xbox 360 alpha test console & output


Also buried in there is a new MIPS variant, the emips along with a donated NetBSD port!

Sadly I had no luck running NetBSD….

Default: 0/ace(0,0)/netbsd
boot: 0/ace(1,0)/netbsd
Loading: 0/ace(1,0)/netbsd
Starting at 0x80020000

memory segment 0 start 00000000 size 10000000
memory segment 1 start 10000000 size 00100000
Too much memory in cluster 0, trimming memory to range 00000000..08000000
Too much memory, ignoring memory range 10000000..10100000
pmap_steal_memory: seg 0: 0x50b 0x50b 0x7fff 0x7fff
pmap_steal_memory: seg 0: 0x54b 0x54b 0x7fff 0x7fff
pmap_steal_memory: seg 0: 0x54d 0x54d 0x7fff 0x7fff
Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
2006, 2007, 2008, 2009, 2010, 2011
The NetBSD Foundation, Inc. All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
The Regents of the University of California. All rights reserved.

NetBSD 5.99.48 (RAMDISK) #0: Tue Mar 15 01:01:14 UTC 2011
Xilinx ML50x (eMIPS)
total memory = 128 MB
avail memory = 120 MB
sysctl_createv: sysctl_create(no_sa_support) returned 22
mainbus0 (root)
cpu0 at mainbus0: Toshiba or Microsoft eMIPS CPU (0x70401) Rev. 1 with software emulated floating point
cpu0: 64 TLB entries
ebus0 at mainbus0
pid 0(system): trap: cpu0, TLB miss (load or instr. fetch) in kernel mode
status=0x2000000, cause=0x8, epc=0x8002d5c8, vaddr=0xd0000000
tf=0x8054cc78 ksp=0x8054cd18 ra=0x8002d5b8 ppl=0xd0000000
kernel: TLB miss (load or instr. fetch) trap
Stopped in pid 0.1 (system) at 0x8002d5c8: lw v0,0(s0)

Maybe someone else will have better luck.

— edit, it seems Microsoft has a NetBSD 4.01 download, here. And it boots!

Qemu ARM, MIPS & PowerPC images…

Well I was thinking of building something like this, but someone did the work for me….

You can find various images here.

So needless to say, a special thank you goes to the dietpc guy… These are all set for MS Windows users, just download the VM you want, and you are ready to go. The only ‘issue’ I had with the PowerPC one, is that I needed to run fsck on the root and reboot it…. (remember the root password is foobar).

Other then that it seems happy as it can be.

root@dietpc3-dev-ppc:/usr/src/f2c# cat /proc/cpuinfo
processor : 0
cpu : 740/750
temperature : 62-64 C (uncalibrated)
clock : 1000.000000MHz
revision : 3.1 (pvr 0008 0301)
bogomips : 40.44
timebase : 16605783
platform : PowerMac
model : Power Macintosh
machine : Power Macintosh
motherboard : AAPL,PowerMac G3 MacRISC
detected as : 49 (PowerMac G3 (Silk))
pmac flags : 00000000
pmac-generation : OldWorld

I wouldn’t dream of really benching it, but this is better then blindly cross compiling as you can check your work…

The downloads are quite sizable about 450mb each… but it is a complete run & go linux environment.

And here is a gratuitous screenshot: