[jornada] Jornada 820

Francois-Rene Rideau fare@tunes.org
Fri Jan 30 02:04:30 CET 2004

Dear 820 users,

I suppose the jornada820@lists.linux.it is better fit
than jornada@handhelds.org for technical questions.

On Thu, Jan 29, 2004 at 07:29:19PM -0500, G Almasi wrote:
> Date: Thu, 29 Jan 2004 19:29:19 -0500
> From: G Almasi <galmasi@optonline.net>
> Subject: Re: [jornada] Jornada 820
> To: jornada@handhelds.org
> On 2004.01.29 08:25 Michael Cheselka wrote:
> >Is there a way to put hpcboot in a "Start Up" directory
> >and pass j820 to it so as soon as WinCE comes up, Linux
> >would follow automatically, making WinCE just part of
> >the boot chain?
> That's a WinCE question, so I'm not qualified to answer.

> But: once Francois-Rene gets finds out what devic
> is corrupting the low regions of RAM, and
> we can turn that device off, the WHOLE of the Jornada's
> memory will be accessible to Linux. This implies that
> there will be no safe spot for WinCE to hide in while
> Linux is running, so any Startup folders you set in WinCE
> will be wiped out by Linux.

Actually, if we identify which portions of memory to save,
it could be possible to restore the machine to a working state
before Linux initiates a cold boot of switches off the power.
If you want to gather the information about how to do it,
the first thing would be to collect a snapshot of the system memory,
after filling most of it (malloc'ing the exact amount thanks to dichotomy)
with an identified pattern (like 0xDEADC077),
loading blob into video memory so that it doesn't overwrite anything,
and sending a compressed image through the serial line.
Or maybe just allocating a big buffer (4MB),
and making three snapshots of the memory while in super-user mode,
and saving the proceedings to a file, all the while being in WinCE.
Then we'd have a working system to restore;
or better - maybe we can figure out which system fields to preserve.
I'm not enthusiastic for doing this job myself, though.
(For one, I'm not willing to hack hpcboot or another WinCE program
into doing what's required for this snapshot.)

> A much better question you should ask is "when are you
> going to make the power button work in Linux, so I can
> put my Jornada to sleep instead of killing the kernel?"
> I dearly wish I had an answer.

Hey. Someone should really port Schemix to the 820,
so as to interactively develop kernel.

>> How soon before one can webbrowse and play mp3s under
>> Linux?
> How soon indeed. On today's digest I saw a reference to
> OpenZaurus - need to look that up, may solve the webbrowse
> question. As for sound  ... I don't know for sure where
> the sound hardware is on this machine, although I have a
> shrewd guess that it may be hiding behind the MCP device.

Hey, maybe a non-kernel hacker can develop a userland distribution
for the J820 as a chroot'ed environment on his Zaurus?
After all, the Z should be backward compatible with J820 binaries
(though I suspect the reverse isn't true --
a StrongArm won't run XScale binaries),
and most of the userland (except device configuration) will be the same.

[ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ]
[  TUNES project for a Free Reflective Computing System  | http://tunes.org  ]
You worry too much about your job.  Stop it.  You're not paid enough to worry.

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