[openbeos] Re: Ports

  • From: "François Revol" <revol@xxxxxxx>
  • To: openbeos@xxxxxxxxxxxxx
  • Date: Mon, 16 Jun 2008 13:44:06 +0200 CEST

> Nicholas Blachford wrote:
> > Is anyone considering or looking into an ARM port of haiku?
> None that I'm aware of.

As I said, Ithamar, me, and someone else who asked on IRC, can't recall 
who.

Also note, the only (relatively) easy targets would be those that have 
an mmu, which are quite rare on arm, at least on the low end versions.
The ARM world is very scattered in terms of features and roadmap, and 
is not easy to follow though...

For example the GP2X has 2 identical cpus, except only one has an 
mmu...
http://en.wikipedia.org/wiki/GP2X
It should however be possible to use the 2nd one to run kernel threads 
maybe, or most of the kernel if we make sure we do not imply direct 
userland vm access from kernel (ie. generalize memcpu_user()).
Plus I heard below ARM11 there is no cache coherency hardware support 
or anything else required for SMP...
Though ARM11 allows that, which means we'll have to consider setting 
B_MAX_CPU_COUNT to 1 to allow to optimize out SMP code, but OTH it will 
prevent supporting SMP at all.

> > On a similar note, how easy / difficult / impossible is it to 
> > change 
> > Haiku's UI?
> It depends on what part of the UI you're referring to. If you're 
> referring to adapting Haiku's desktop UI to, say, an Eee PC, I doubt 
> that really any changes would be required. To go smaller to an 
> embedded 
> device (PalmPilot, etc) it would probably just involve a new window 
> decorator and a replacement for Deskbar and Tracker.

Some changes might be needed to optimize the layout (default to 
fullscreen windows, merged menubar/toolbars (we need a standard toolbar 
class anyway)), and even more if you intend to target devices without 
touchscreen who use a joystick-like HID, but I think primary targets 
would be PDA and PDA-like smartphones.

> > Also, how flexible it is in terms of devices that may have a 
> > keyboard or 
> > touch screen but no mouse?
> That should just be a matter of the input_server add-ons which are 
> available. The input_server makes it easy to swap between an on-
> screen 
> keyboard and a hardware one, for example. The rest of the system 
> doesn't 
>   really care whether you're using a mouse, touchpad, or whatever.

As I said already, touchscreen are just a special kind of tablet that 
have absolute coords that match pixel pos.
For devices not having a touchscreen, The joypad can emulate arrow 
keys, and I already started writing a T9 input method.
I also started a pen input method that can serve to incorporate an 
handwriting recognizer.
I shall commit those to svn, I need versioning on that too.

> This could probably be a nice niche market for Haiku, considering its 
> low hardware requirements, if someone had sufficient interest in 
> writing 
> for the hardware. The only problem is that the current developers are 
> concentrating on the alpha 1 for x86. Someone new would probably need 
> to 
> step up for work on it to begin, and I don't know the details  of 
> Haiku's kernel-level architecture, but I have a feeling that there'd 
> be 
> more than a little work required to get it running on ARM.

Maybe if we find some company wanting to explore the possibility...

François.

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