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Emulation... Yuck.

:).

What's one more abstraction layer? (heck, an emulated RISC OS machine - with an OS mostly written in asm IIRC - could very well end up with less layers than a typical software stack that we use nowadays(?))
Especially in times when we readily accept virtual machines, and have no lack of processing power.

And perhaps there's also the "green" aspect that you should keep in mind and at least point out ;P (you know, for those who might be interested only about RISC OS ...and getting another piece of future-electronic-waste, hardly used, for what they probably could accomplish just as well - if not better - under emu?)

Edited 2012-05-30 23:14 UTC

I think the Raspberry Pi would definitely help in the "green" department. Five volts at 700 milliamps is less power than those LED light bulbs that are supposed to be so "green".

Not in the scenario it was about. If somebody just wants to check out RISC OS (nostalgia, curiosity, whatever), occasionally* toy around with it, then the resource & energy consumption of manufacturing (plus shipping?) will most likely tend to dwarf any energy usage from occasionally running RISC OS in an emulated fashion on a laptop.
(and I wonder how often those people will leave their PC on anyway, when toying with RPi...)

* Let's be honest here, at best minuscule number of people will be retiring their laptop to use RPi as a main machine. And this is just about mentioning the emulation possibility to those who won't, instead of rejecting it like that; it's just prudent and honest, IMHO.

Edited 2012-05-31 21:02 UTC

Yeah, kinda silly. Fixed it!

I want to pick at Thom too! 700Ma hurts my eyes. 700mA please.

I'm not at all jealous Thom got his before me

youd be way better off with a mele a1000 for that purpose. no codec limitations, already a case and you can plug in a 2.5" sata drive.

I was up when the released the pi trying to get one. Mine is still supposedly 2 weeks out. Frankly though work has gotten me so I wouldn't be able to contribute so well.

Edited 2012-05-30 23:42 UTC

XBMC on the RasPi is stunning. I use the Raspbmc and it plays all the youtube and BBC iplayer better than my laptop, with no playback issues at all. The installation of Raspbmc was piss easy too, you just need a blank sd card. The only issue is the menus are a slightly sluggish (I haven't even needed to over clock) and there is a 5 second delay before buffering starts which is annoying, but once it starts playing there are no issues. (mpeg4 does not work but I don't have any), I use the Android XBMC remote control.

Ha Ha Thom I ordered my Pi a day after you and we both got exactly the same delivery date, but mine arrived about a week ago.

Watch that S2 power adapter as my pi would crash occasionally using it, you really need a greater than 700mA charger. The debian image is very flaky with lots of rough edges and very slow. The very new Raspian OS is looking very good (with hardware floating point) and runs faster. run the rpi-updater to get the latest kernel with pre-emption turned on on Debian

some people were saying that the 1080p "killa sample" h264 1080p clip runs smooth on an a10 processor and does not on an rpi. but that's just a benchmark.

I think you should make it a robot, so it can follow you around and do all of these tasks. Though if you can make a robot that can connect itself to the tv alone that is already fairly impressive, especially considering how finicky my PS3's HDMI connection seems to be.

I was also quite sad about this, even though I don't plan on writing an OS or doing anything close to that anytime soon. Might not have purchased one had I known, though I guess in designing such a cheap system their choice in chipsets may have been limited ... just a guess though.

What probably also played a role, I guess, is how the RaspberryPi Foundation is a stone's throw away from the UK Broadcom R&D branch in Cambridge - which also designs that line of SoCs, it seems.

And how one of RPi fathers (even the director of RPi Foundation?) works as a chip designer at Broadcom.

http://www.raspberrypi.org/about
http://en.wikipedia.org/wiki/Alphamosaic

Edited 2012-05-31 18:27 UTC

Technically, the GUI is not part of the OS, so why should this hold you back to write your own OS for ARM?

There are lots of interesting other tasks in writing an OS, like memory-management, filesystem drivers, etc... no binary bob prevents you from doing that :-)

It's actually a bit backwards. The GPU is the main processor and the ARM is an auxiliary. When the system is started, the GPU wakes up, fetches the blob from the SD card, and that blob contains a program that brings up the ARM.

No matter what OS runs, the blob is needed in order to boot the ARM.

That blob can be anything capable of running in the L2 cache, as long as it's named "start.elf" in the FAT-formatted first partition of the on-board SD card. Who knows, perhaps someone could get Contiki OS in there?

I got my raspberry pi last Saturday and and been working on a port of x86 OS and already got it to use GPIO and setup frame buffer and display a image to screen, in bare metal mode.
All in full asm, so its doable.

Hi Dex,

Can you tell me, which assembler and command line parameters did you use to compile the assembly?
Thanks!

Sure, i used FasmArm, it uses fasms basic core, so you need to use some unusual instructions.
Basic R-PI bare boot.
[code]
format binary as 'img'
org 0x00000000
use32
;------------------------------------------------------
; This is where the GPU jumps to
;------------------------------------------------------
Start:
b RealStart
b EndlessLoop
b EndlessLoop
b EndlessLoop
b EndlessLoop
b EndlessLoop
b EndlessLoop
b EndlessLoop
;------------------------------------------------------
; Just put a loop here
;------------------------------------------------------
EndlessLoop:
b EndlessLoop
;------------------------------------------------------
; Leave space here has GPU may add things like
; Mac address
;------------------------------------------------------
times 0x8000- ($-Start) db 0 ; this may be needed (that the offset for linux kernels)
;------------------------------------------------------
; The "kernel" will start here.
;------------------------------------------------------
RealStart:
b RealStart
; Your code will go here
[/code]
This is the very basic code you need, use FasmWArm its a ide that comes with the window ver of fasmarm (can run in wine under linux).
Just save the above code as kernel.asm and click compile and it will out put a file called kernel.img.
Just format a sd card fat32 and add the above file plus
bootcode.bin loader.bin start.elf

You can get them here:

https://github.com/raspberrypi/firmware/tree/master/boot

Thats it, it will boot your code, not that it will do anything, but thats up to you to add the code.
I am working on a tut with example code.
Example the green OK led is interfaced to GPIO16.
This outputs a flat bin file, no links etc needed 8).

Too ad Tom Live too far from me, i could lend him my n9 or pre3, i have both, and don't see a review about both is a big miss here.

See my comment below. The only issue I've had so far is that it won't give me the full 1600x900 resolution on my monitor; it limits me to 1280x720 no matter which mode I set via config.txt. But, at least it's the correct aspect ratio; Fedora limited me to a weird tiny VGA resolution and Debian gave me something like 1536x864 that left a black border around the image.

Otherwise, using Arch on the Pi feels pretty much like using it on an older desktop; slow, no video acceleration in X but otherwise a fairly complete computing experience.

Once I've had time to really dig in I'll look at submitting an in-depth review here.

And I got mine today... I'll soon know if it fits the purpose for my project.