Prex OS on Sigmarion 3

I discovered an OS that runs on ARM, x86, and PowerPC devices, including Game Boy Advance, and I was looking at the downloads in the URL below.

http://prex.sourceforge.net/

To my surprise, there was a floppy disk image for i386 without mmu.
I decided to test it on my Sigmarion 3 if it will work.

I copied the BOCHS 1.4.1 to the root folder on my Sigmarion 3 (not SD card).
Then, it took a long time to load, and a crazy output of it running at 1600MHz appeared, with 1MB of RAM. lol

The minimum requirement is: (from Prex website)
Processor: 32-bit Processor (x86, ARM, PowerPC)
Memory: 256KB of RAM (Kernel < 25k bytes)
Timer: programmable interval timer

Wondering what Prex is?

"Prex is an open source, royalty-free, real-time operating system for embedded systems. It is designed and implemented for resource-constrained systems that require predictable timing behavior. The highly portable code of Prex is written in 100% ANSI C based on traditional microkernel architecture. " (from Prex website)

-stingraze

Edited by stingraze 2022-03-26 4:25 AM








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sigmarion3-prex.jpg (124KB - 0 downloads)
sigmarion3-prex2.jpg (130KB - 0 downloads)

Interesting... and nice to see someone playing with Bochs. But... what does it do? What can you do with it that you can't with CE?

Obviously emulating realtime OS totally destroys any value it has.

lol. Value?

Umm... same value Windows CE has, but makes you feel a bit more advanced? jk. Yeah, practically it makes you have more knowledge how embedded OS works since it is a very small open source OS. Windows can't be recompiled, at least not legally...

haha, the ultimate truth of why anyone uses a cli based OS - to feel smug

Fair enough. If you can recompile it though, wouldn't it be more efficient to recompile it for SA1100?

Even if you do, I wonder how you would boot it.

Yeah, recompiling for SA1100 will be cool. Also for XScale.

If someone knows how to use hpcboot, one can boot a OS… the holy grail of Sig 3. Haha.

Also a fun fact, there is actually an ASIC on this device, didn’t know that until a few months ago.
Japanese site: https://z.apps.atjp.jp/sig3/ (board image, parts no. etc.)

Edited by stingraze 2022-03-26 2:42 PM

Oh, do you mean that it would be faster to emulate? Probably only marginally because Windows executable operates in different environment and has different guarantees, so even if you have binary code with same ISA you cannot execute it without analyzing it.

No, run natively; admittedly you'd need a bootloader / bootstrap process which would be harder to invent.